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Title: Galileo and his Judges

Author: F. R. Wegg-Prosser

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GALILEO AND HIS JUDGES.




  GALILEO AND HIS JUDGES


  BY
  F. R. WEGG-PROSSER.


  LONDON: CHAPMAN AND HALL,
  LIMITED.
  1889.
  [_All rights reserved._]




  CHARLES DICKENS AND EVANS,
  CRYSTAL PALACE PRESS.




PREFACE.


There is no name in the annals of science which has been the occasion
of so long and fierce a controversy as that of Galileo. The historian,
the astronomer, and the theologian have all had a share in it.
Sometimes there has been a pause in the strife, and the question has
been allowed to rest; but after a while another disputant has rekindled
the embers, and the struggle has recommenced. This has been the case
within the last few years, some writers of considerable ability having
appealed to the history of Galileo in order to give point to opinions
that they wished to advance. During all this time, if there has been
unfairness on one side, there have been injudicious zeal and inaccuracy
on the other.

These circumstances must form my apology for interfering in a dispute
already so prolonged and so envenomed; and it has appeared to me that I
may without presumption hope to amend the errors to which I have just
alluded, if in no other way, at least by stating correctly the facts
of the case. I do not, however, undertake to write a full biography of
the great philosopher, or to give a detailed account of his numerous
contributions to the scientific literature of his day; I confine myself
principally to those great crises in his life which have given rise to
so much discussion, and which have chiefly contributed to make him a
name in history.




CONTENTS


        Preface           v
        Chapter   I       1
        Chapter  II      13
        Chapter III      42
        Chapter  IV      78
        Chapter   V     136




GALILEO AND HIS JUDGES.




CHAPTER I.


Before entering on any details relating to Galileo’s life and works,
I propose to give a brief sketch of the progress of astronomical
knowledge up to his time; for without this, one cannot appreciate
correctly the value of his contributions to science, a value
exaggerated or underrated by different writers, each according to his
respective bias.

The primitive conception of the Earth as a vast plain with the ocean
flowing round it, and the solid firmament in the sky above it, with the
Sun, Moon, and Stars driven across by some mysterious agency, need not
be noticed from an astronomical point of view; it appeared naturally
in ancient poetry and in the forms of speech adopted and continued by
popular usage; but it is not necessary to dwell upon it.

The first astronomers with whom we are acquainted were the Greeks,
though it is said by some writers that the Chaldeans and Egyptians were
really the original astronomers of the ancient world, and what the
Greeks knew was borrowed from them.

The vast majority of men from the earliest times down to the birth of
Galileo believed that the Earth was the centre of the universe, round
which the Sun, Moon, and Stars revolved every twenty-four hours; round
which, also (as careful observers had perceived), the Sun had an annual
motion, progressing through the various signs of the zodiac; moreover,
it had been noticed that the planets moved round the Earth, though at
widely differing periods.

Yet there had been some few men, exceptionally gifted, who had guessed
(and truly so) that the popular conception was a wrong one. It is said
that the old Greek philosopher, Pythagoras, taught his disciples that
the Sun was the real centre of our system, and that the Earth and
planets circulated round it; but he does not seem to have openly and
explicitly published his doctrine, though the tradition of his having
so taught has always existed. If he taught it, however, he stands
almost alone among the ancients. There were two great authorities
in particular, whose opinion carried immense weight, and who were
both decided in holding that the Earth was the centre, and the Sun
a revolving planet. The first of these, Aristotle, has exercised an
influence over succeeding generations which is simply marvellous.
How vast was the weight of his name as a philosopher in the age of
the schoolmen is well known to every one who has ever glanced at the
greatest work of the greatest intellect of that age, the “Summa” of
St. Thomas Aquinas. This celebrated writer quotes him as “philosophus,”
in his opinion _the philosopher par excellence_, and besides his
general appreciation of him as thus shown, he wrote an elaborate
treatise on the “Astronomy” of Aristotle.

Nor has this influence been confined to the schoolmen; it has remained
ever since, even to this day and in this country, where in the
University of Oxford his great work on ethics is still a standard book
of study. At the time of Galileo, such was the reverence felt towards
his authority in Italy and in Rome, that the Peripatetici, as those
who specially belonged to his school were called, were probably quite
as indignant with the revolutionary astronomer for disregarding the
teaching of their philosopher, as for going counter to the literal
interpretation of Scripture.

But in pure astronomy, apart from all other philosophy, the greatest
of all ancient writers was Ptolemy, who in the second century of the
Christian era wrote a work called the “Almagest,” which is a complete
compendium of the science as known at that date. Ptolemy probably
borrowed very much from his great predecessor, Hipparchus, who has been
called the father of astronomy, and who was the first to discover--to
take a remarkable instance--the phenomenon known as the precession of
the equinoxes, involving as it does the difference in length between
the solar and sidereal years. The system of Ptolemy was briefly this:
The heavens and the Earth are both spherical in form--the Earth being
immovable in the centre, and all the heavenly motions taking place in
circles. For this he gives his reasons--sound and good reasons for the
spherical shape of the Earth; unsound and mistaken, however, for the
denial of the Earth’s rotation on its axis, an opinion he evidently
knew had been maintained by some persons; one important argument
on this latter head being that if the Earth rotated with the great
velocity necessary to carry it round in one day, it would leave the air
behind it. He places the Earth (as already said) in the centre, then
the Moon as the nearest planet revolving round it, the next Mercury,
then Venus, then the Sun, and beyond these Mars, Jupiter, and Saturn.
All moved in circles, but since, with the exception of the Sun and
Moon, simple circles would not account for the motions, he supposes
small circles in a retrograde direction forming loops upon the main
circle, which he calls _epicycles_; undoubtedly following in this
respect, Hipparchus, who three centuries before had struck out the
same idea. It is curious that Ptolemy’s arguments (as above mentioned)
show clearly that in his day there were some persons, though their
names have perished,[1] some one or two philosophers endowed with a
marvellous insight into Nature, who had guessed at the true solution
of the great astronomical problem; but they left no enduring mark on
their age. The system of Ptolemy accounted for all the phenomena of
the heavenly bodies that could be observed without the use of the
telescope; naturally it held undisputed sway for many generations.

The first writer who revived the doctrine of Pythagoras as to the
Earth’s movement (if, indeed, Pythagoras ever really taught it) was
Nicholas de Cusa; he was a German by birth, having, in fact, been born
at Trèves, in 1401; but he was educated in Italy. He rose to a high
ecclesiastical position, and was created cardinal by Pope Eugenius IV.,
in 1448; his book just alluded to was entitled “De Docta Ignorantia,”
and was dedicated to Cardinal Cesarini.

The first, however, whose work obtained any great notoriety, and
who upheld the doctrine that the Earth revolved around the Sun, was
Nicholas Kopernik, commonly called by the Latinised form of his name,
Copernicus. He, too, was a German, born at Thorn, in 1473; he studied
for a time at the University of Cracow, and like Nicholas de Cusa,
afterwards in Italy, and was subsequently raised to the ecclesiastical
dignity of a Canon. It is probable that he was not a priest (though he
is frequently spoken of as such), but a Canon in minor orders. In 1500
he was appointed professor of mathematics at Rome; and such was his
scientific reputation that he was consulted by the Council of Lateran,
held in 1512, on the question of the reform of the calendar--a reform
carried out at a later period by Pope Gregory XIII.

The system of Copernicus was well received at Rome. A German disciple
of his, John Albert Widmanstadt, in the year 1533, expounded it before
Pope Clement VII., and produced a very favourable impression. Nor was
the favour shown to Copernicus and his teaching ever withdrawn at Rome;
his great work, “De Revolutionibus Orbium Cœlestium” (published, it
is said, by the advice of Cardinal Schunberg, Bishop of Capua), was
dedicated to the reigning Pope, Paul III.; nor does he appear to have
received at any time the least rebuke or discouragement from the Holy
See; he died, however, immediately after the printing of his book, in
May, 1543.

Copernicus supposed the heavenly bodies, the Earth included, to revolve
round the Sun in _circles_; but, as it was evident that they did not
exactly do this, he used the theory of epicycles, and supposed each
planet to make two revolutions in each epicycle for every revolution
round the Sun. The true solution of the difficulty was due to Kepler,
who lived in the next century, and who discovered that the planets
moved in _ellipses_. Copernicus held, and, of course, held truly, that
the Earth revolves on its axis, thereby causing the apparent diurnal
motion of all the heavenly bodies from east to west.

Owing to his work having been the first of any great importance that
maintained argumentatively the system called _heliocentric_, that is
to say, in which the Sun is the real centre, round which the planets,
including the Earth, revolve--for the treatise of Nicholas de Cusa
does not appear to have had any extensive circulation--it is usual
to speak of this system as the _Copernican_ one, notwithstanding the
errors from which its great author was unable to extricate himself, and
which have long since been rectified by subsequent writers; so that
even at this day we retain the name.

It is always useful in scientific subjects to introduce a definition;
and this is my definition of the sense in which I employ the word
Copernican, that it is simply as opposed to the system in which the
Earth is the centre of the visible universe, and the Sun revolving
about it. It is, in fact, less accurate but more convenient than the
employment of the Greek words heliocentric and geocentric to denote
the two systems. Greek words, no doubt, abound in our scientific
vocabulary, as the following plainly show: astronomy, geology,
geography, barometer, thermometer, microscope, telescope; but these
have become naturalised in our language by long use, which heliocentric
and geocentric have not as yet been.

After Copernicus there arose an astronomer of great merit, a Dane,
Tycho Brahé by name, who attempted to start a fresh system--a
modification, in fact, of that of Ptolemy. He made all the planets
revolve round the Sun, and the Sun, accompanied by the planets, round
the Earth. He deserves great credit for his painstaking observations;
but he lived just before the invention of the telescope--or, at least,
before it was used for astronomical purposes--and, therefore, was
under an infinite disadvantage. His chief objection to the system of
Copernicus was one at which a modern astronomer would smile, but which
in those days seemed very weighty--namely, the enormous distance at
which you must suppose the fixed stars to be situated, if it were true.
The philosophers of that age did not like to admit such a waste of
space as that which must intervene between the orbit of Saturn and the
stars. And, on the Copernican theory, if the stars were not situated at
an immense, almost infinite distance, they ought to appear to move in
a way they certainly do not. Tycho Brahé was born in 1546. His theory
never made much way; it had not, I imagine, sufficient elements of
probability to recommend it generally; while the subsequent invention
of the telescope, and the works of Kepler and Galileo, coming so soon
after Tycho Brahé, prepared the way for that almost universal reception
of the Copernican system which we have since witnessed. I shall refer
later on to Tycho and his observations.

Such, then, was the state of astronomical theories in the latter
part of the sixteenth century. Enlightened men like Copernicus had
guessed--not accurately, it is true, but with a considerable approach
to accuracy--at the real facts of the case. Tycho Brahé (who, I
suspect, would have been converted to Copernicanism if his life had
been prolonged) had suggested a system of compromise not likely, in
the long run, to satisfy any thoughtful mind; while the bulk of men,
even the learned, adhered to the old Ptolemaic scheme. Something,
however, now occurred which was destined to work, sooner or later, a
complete revolution in astronomy. The telescope was invented, and, at
the same time, there arose a man who knew how to use it: that man was
Galileo. He was not the inventor of it, for it was first constructed
in Holland or Belgium; yet he had the energy and the skill to make a
telescope, without having previously seen one, simply from the account
he had heard of the instrument. The telescope that he constructed,
which still bears his name, was the simplest possible. It was of a
form now disused excepting for opera-glasses and for the far more
powerful binocular field-glasses with which we are so familiar; but for
telescopes properly so called an improved principle has long since been
introduced. Galileo was the first man that ever, so far as we know,
turned the telescope upon the heavens. How he was rewarded for his
pains we shall presently see; and I propose to introduce a narrative of
the principal events in his life, since there are no means for forming
a judgment so valuable as having the facts of the case clearly before
the mind.

For most of the facts I am indebted to M. Henri de l’Épinois, whose
elaborate article in the French publication known as _La Revue des
Questions Historiques_ is of the highest value; as the author of this
article has done what I suspect very few writers on Galileo have even
attempted to do, namely, to inspect the documents preserved in the
Vatican bearing on the process, some of which he gives at full length.
Not having myself had the same advantage, I yet feel that I am treading
on safe ground when I take my facts from M. de l’Épinois; for there
is scarcely a statement that he makes for which he does not give his
authority, whether from the documents just mentioned, or from Galileo’s
own letters, or from other trustworthy evidence.[2]

To treat of Galileo, and to pass over the events which brought him
into collision with the ecclesiastical authorities, would of course be
impossible, nor is it easy to touch upon these matters without having
some standpoint of one’s own--some principle to guide one, some basis
from which to argue. I do not shrink from stating that I write from a
Catholic standpoint; but without entering minutely into those subtle
questions which are the province of the trained theologian.

As, however, a good deal of the narrative is connected with the
action of the Roman Congregations, as they are termed, it may not be
superfluous to explain briefly the nature of these institutions. They
are formed by the selection of certain Cardinals, one of them acting as
Prefect of the Congregation, to whom are added other ecclesiastics as
consultors and as secretary. The Congregation of the Index, to which
reference will hereafter be made, was instituted not long after the
Council of Trent, by Pope St. Pius V., and has for its duty, as its
name implies, the pointing out to the faithful people such books as
they ought to abstain from reading. The chief consultor of the Index
is the “Master of the Apostolic Palace,” whom I shall have occasion
to mention more than once in connection with that Dialogue of Galileo
which brought him into such serious disgrace at Rome.

The Congregation of the Inquisition--I need hardly say, not to be
confounded with the Spanish tribunal of that name, which was founded at
an earlier period, nor with similar tribunals in other countries--was
erected in 1542 by Pope Paul III., and besides the other officials
attached to it, had certain theologians called “qualifiers,” whose duty
it was to give an opinion to the Congregation on questions submitted to
them.

These two Congregations, as well as several others which it is not
necessary to enumerate, still exist, their functions being somewhat
modified by the changing circumstances of the age. Their action is for
the most part confined to matters of discipline, but they sometimes
have questions of doctrine and moral obligation referred to them by the
Pope, from whom, of course, they derive all authority that they possess.

I do not here undertake to show the advantage and utility of these
Congregations, or of any other institutions connected with the
discipline of the Catholic Church. From the remarks I have just
previously made, it will be understood that I take all this for
granted, and that I feel justified in doing so. Those who differ from
me will, I trust, excuse me when they find that this conviction on my
part does not interfere with the impartial fairness of my narrative.

Galileo, whom I believe to have been a devout Catholic, would, if he
were here to speak for himself, agree with me in principle, however
he might complain of the action of the Roman Congregations in his own
individual case.

We shall then, as we proceed, inquire whether this celebrated
philosopher was, as some imagine, a hero and a martyr of science, or,
as others think, a rash innovator, who happened by chance to be right,
but who had little or nothing but vain and foolish arguments to adduce
in support of his doctrines. Perhaps we shall find that such critics,
on either side, are but imperfectly acquainted with the facts of the
case.




CHAPTER II.


Galileo Galilei Linceo--for such was his name in full--was born at
Pisa, the 18th February, 1564. When about seventeen years old he
commenced studying mathematics and physical science at the University
of Pisa, and later on, in 1585, he came to Florence, in order to go
through a mathematical course.

He seems to have been wholly free from the sceptical and irreligious
spirit which unhappily warps the judgment of some scientific men
in our own day. His moral conduct, however, in early life was not
irreproachable, and it is recorded of him that he had a _liaison_ with
a lady named Maria Gamba, who became the mother of three children; but
this illicit attachment did not last very long, and a separation took
place, after which he saw Maria Gamba no more, and she was subsequently
married to some other person. He then entered the celebrated monastery
of Vallombrosa, where he was a novice for a short period; but, having
apparently no vocation for the religious life, he left the monastery,
and resumed his former pursuits. At the age of twenty-five he was
appointed professor of mathematics at Pisa, the Grand Duke of Tuscany
having invited him there on the recommendation of Cardinal del Monte.
Here it was that he first excited hostility by attacking the theories
of Aristotle on physical science, a thing not to be done with impunity
in that age.

I have already alluded to the telescope constructed by Galileo, and it
is scarcely necessary to say that such an instrument, however simple
and rudimentary in its construction, could not fail to reveal to an
intelligent observer truths hitherto unknown. It was discovered that
the planet Jupiter had satellites, that Saturn had a ring, that Venus
passed through phases like the moon, that there were spots on the
Sun; this last discovery having been made about the same time by the
learned Jesuit, Father Scheiner, and by Fabricius. It was not, I think,
until the year 1610 that Galileo published his work called “Nuntius
Siderius,” in which he recounted the results he had obtained. This work
seems to have provoked some considerable opposition, but Galileo was
supported by the approbation of his patron, the Grand Duke of Tuscany.
In the following year, 1611, he went to Rome, and here he was well
received and treated with distinction by prelates of high position,
and even by the Pope then reigning, Paul V. Moreover, when, in the
year 1612, he published another work, which he called “Discorso sui
Gallegianti,” he met with general approval, and no less a person than
Cardinal Maffei Barberini, who afterwards became Pope under the title
of Urban VIII., is stated to have declared that he was in all points of
the same opinion as Galileo.

Now it is quite true that incidental conversations, passing, perhaps,
through the hands of two or three persons, are not to be greatly relied
upon. It is also to be remarked that men in the position of Cardinals
or ecclesiastics of high rank may often look with toleration and even
favour on opinions stated in a guarded and hypothetical way, and yet,
if called on to pronounce an official judgment on such opinions, would
feel it a duty to pronounce against them. Nevertheless, there appears
considerable reason for thinking that since Galileo’s reputation stood
so high, and his ability was so manifest, he would have escaped all
censure if he had confined himself strictly to stating his views on the
Copernican system as a scientific hypothesis, and had firmly resisted
the temptation (strong as it was) to allow himself to be drawn into the
Scriptural argument.

This, however, it must be remembered, was mainly the fault of his
opponents. Unable to grapple with the question in its purely scientific
aspect, some zealous anti-Copernicans turned to Holy Scripture for
support--Scripture in its most rigid and literal interpretation; an
interpretation, however, it must in fairness be stated, enshrined in
the traditions of successive generations.

It is said that a monk named Sizi went so far as to maintain that the
Bible contradicted the existence of the satellites of Jupiter. If this
be true (which one cannot help doubting), we may well say that amongst
all the perversions of Scripture in which human fancy has indulged,
there is scarcely any one more monstrous; and we must not imagine that
all the Biblical arguments used against Galileo and Copernicus were so
unreasonable and exaggerated.

It was in 1613 that our philosopher published at Rome another work,
entitled “L’Istoria e Dimostrazione Intorno alle Macchie Solari.” It
was, generally speaking, well received, though he drew a conclusion in
favour of the Earth’s rotation on its axis.

The controversy, however, became still keener on the all-important
point of the interpretation of Scripture. Now that we can look back
on the events of that day with all judicious calmness, we may well
blame Galileo for having let himself fall into so dangerous a snare;
but there was some excuse for him, attacked as he was on this very
ground of the supposed incompatibility of his hypothesis with the
teaching of Scripture; and so he unfortunately committed a grave error
of judgment in grappling himself with a religious difficulty which, if
wise, he would have left entirely to theologians. It may be said that
this is not what we should naturally expect. We should suppose that
the ecclesiastical authorities would welcome any attempt to prove that
new scientific theories were not irreconcilable with the Scriptural
narrative, and possibly such would be the case at the present day;
but in those times it was certainly otherwise, and I am not quite
sure whether the tone and tendency of Rome (that is to say, Rome as
the centre of ecclesiastical tradition and authority) is not still,
as it was then, in favour of the same rule of conduct--that, namely,
which keeps a scientific man to his own province, and leaves to the
authorities of the Church the duty of reconciling physical theories and
speculations with the teaching of Holy Scripture. On this last-named
point I need not say I speak with the utmost diffidence; but on the
historical question, as to whether that was the feeling which animated
Popes and Cardinals in Galileo’s day, I think there can be very little
doubt.

Now, as the controversy became embittered, a certain Father Cassini, a
Dominican, preaching in the Church of Santa Maria Novella at Florence,
attacked the Copernican doctrine as taught by Galileo; this aroused the
wrath of the philosopher, and he wrote (on the 21st December, 1612) a
letter to a Benedictine monk, Father Castelli, protesting against the
interpretation of Scripture which Father Cassini had used; and while
so protesting, over-stepping, it appears, the limits of prudence. The
result was that this unguarded letter was denounced by Father Lorini to
the Cardinal Prefect of the Congregation of the Index.

The consequence of this was that in the early part of the year 1615
there commenced a process which in the following year had an important
issue. It is said that in the month of March, 1615, Cardinal del Monte
and Cardinal Bellarmine had a conversation on the subject of Galileo
and his teaching, the result being that they both agreed on this one
point: that Galileo ought to avoid entering on the interpretation
of Scripture, this being a matter reserved to the ecclesiastical
authorities.

Galileo was not then at Rome; and two influential friends of his, Mgr.
Dini and Prince Cesi, advised him to be quiet and silent; such advice,
however, was not to his taste, and he, on the contrary, thrust his
head into the lion’s mouth, confident of ultimate success. He came
personally to Rome, mixed in society, and endeavoured by the use of
such arguments as occurred to him in conversation to refute the ancient
opinions. Several of his friends, including some of the Cardinals,
advised moderation, but in vain; and such was his confidence in his
cause, that in the early part of the year 1616 he actually began to
complain of the delay in the process.

The Pope looked upon his conduct with evident displeasure, and it is
stated in a letter of Guicciardini that on one occasion Cardinal Orsini
spoke to him in favour of Galileo, and he answered that the Cardinal
would do well to persuade his friend to abandon his opinion--adding
that the affair was placed in the hands of the Cardinals of the Holy
Office. After this incident, it is said, the Pope sent for Bellarmine,
talked the matter over with him, and agreed that Galileo’s opinion was
erroneous and heretical. A decided step was now taken: on the 19th
February, 1616, there was sent to certain theologians belonging to the
Congregation of the Inquisition--technically called the _Qualifiers_--a
copy of the propositions, the censure of which had been demanded: 1st,
That the Sun was the centre of the world, and consequently immovable
locally; 2nd, That the Earth was not the centre of the world, nor
immovable, but moved round itself by a diurnal rotation.

The Qualifiers of the Congregation met on the 23rd February, and on
the next day, in presence of the eleven theologians who had been
consulted, the censure was pronounced. All declared that the first
proposition was foolish and absurd, philosophically speaking, and
also formally heretical, since it expressly contradicted numerous
texts of Holy Scripture, according to the proper meaning of the words,
and according to the ordinary interpretation and the sense admitted
by the holy Fathers and theological doctors. All declared that the
second proposition deserved the same censure philosophically, and
regarding theological truth, that it was at least erroneous in point
of faith. The next day, 25th February, Cardinal Mellinus notified to
the Commissary of the Holy Office what had taken place, and the Pope
desired Cardinal Bellarmine to send for Galileo, and admonish him to
abandon the opinion in question; if he refused to obey, the Father
Commissary, in presence of a notary and witnesses, was to enjoin
upon him a command to abstain wholly from teaching such doctrine and
opinion, from defending it, or treating of it; if, however, he would
not acquiesce, that he should then be imprisoned. On the following day,
26th February, this was accordingly done, and Galileo was warned “ut
supra dictum opinionem... omnino relinquat, nec eam de cetero quovis
modo doceat teneat aut defendat verbo aut scriptis,” with the threat
already mentioned in case of disobedience. Galileo promised to obey.

In the beginning of the month of March there appeared a printed decree
of the Congregation of the Index prohibiting five works; and here
we arrive at the curious fact that no work whatever of Galileo was
prohibited by name. The feeling in the high ecclesiastical circles
of Rome seems at that time to have been very much to this effect:
“Let us stamp out the obnoxious opinion, but let us spare Galileo
individually.” The final result (including what took place in after
years) is strikingly contrasted with such expectations, if they
existed. Galileo had to suffer personally, not bodily torture or
incarceration, but humiliation and failure; whilst the dreaded doctrine
of Copernicanism, purified from incidental error and taught in an
enlightened form, has triumphed and reigns supreme. The decree of the
Index is particularly noteworthy, for it is the principal matter with
which we have to deal. After prohibiting certain Protestant books, the
decree proceeds as follows: “And since it has come to the knowledge
of the above-named Sacred Congregation that that false Pythagorean
doctrine, altogether contrary to Holy Scripture, concerning the
movement of the Earth and the immobility of the Sun, taught by Nicolas
Copernicus in his work on the Revolutions of the Heavenly Orbs, and
by Diego di Zunica in his work on Job, is already spread about and
received by many persons, as may be seen in a printed letter of a
certain Carmelite Father, entitled ‘A Letter of the Rev. Father,
Master Paul Anthony Foscarini, on the opinion of the Pythagoreans and
of Copernicus respecting the mobility of the Earth and the stability
of the Sun, and the new Pythagorean System of the World,’ printed at
Naples by Lazzaro Scorrigio, 1615, in which the said Father endeavours
to show that the aforesaid doctrine of the immobility of the Sun in
the centre of the universe and the mobility of the Earth is consonant
to the truth, and is not opposed to Holy Scripture: Therefore, lest
any opinion of this kind insinuate itself to the detriment of Catholic
truth, [the Congregation] has decreed that the said [works of] _Nicolas
Copernicus on the Revolutions of the Orbs_ and _Diego di Zunica on
Job_ should be suspended until they are corrected. But that the book
of Father Paul Anthony Foscarini the Carmelite should be altogether
prohibited and condemned; and that all other books teaching the same
thing should equally be prohibited, as by the present decree it
prohibits, condemns, and suspends them all respectively. In witness
whereof the present decree has been signed and sealed by the hand and
seal of the Most Illustrious and Most Reverend Lord Cardinal of Santa
Cecilia, Bishop of Albano, on the 5th day of March, 1616.”

Here follow the signatures:

  “P. EPISC. ALBANEN. CARD. SANCTÆ CÆCILIÆ.
                    “_Locus_ ✠ _sigilli_.
  “F. FRANCISCUS MAGDALENUS CAPIFERREUS,
                    “_Ord. Prædicat., Secretarius_.”

There followed a somewhat remarkable episode: some opponents of
Galileo having spread a report that he had been compelled to make an
abjuration, and also had had certain salutary penances inflicted on
him, Cardinal Bellarmine gave him a certificate to the effect that
nothing of the kind had taken place, but only that the declaration made
by the Pope and published by the Congregation of the Index had been
communicated to him; in which declaration was contained the statement
that the doctrine attributed to Copernicus on the movement of the Earth
round the Sun, and the stability of the Sun in the centre of the world
without its moving from east to west, was contrary to Holy Scripture,
and so could not be defended or held. It appears that the abjuration
alluded to was a solemn act demanded only from those who were suspected
of unsoundness in the faith, and carried with it some disgrace. Galileo
was naturally anxious to be cleared from such imputation, and the
authorities in Rome willingly met him so far, and avoided all acts
casting a personal slur on him. It is noteworthy that the interview
between Cardinal Bellarmine and Galileo took place after the answers
had been returned by the Qualifiers of the Inquisition, but before the
publication of the decree of the Index. The certificate given by the
Cardinal, to which I have just alluded, was subsequent, and bears date
the 26th May, 1616.

And here we may pause in the narrative, to inquire briefly what was the
effect, in an ecclesiastical point of view, of the decree just quoted,
and of the admonition given by Papal order to Galileo. On the mere face
of it, it cannot surely be maintained that there was any doctrinal
decision, strictly speaking, at all. I do not wish to undervalue the
importance of the disciplinary decision, I think it most momentous;
moreover, the reason alleged for it was that the opinion, the
publication of which was to be forbidden, was contrary to Scripture;
but I fail to see how this last-mentioned fact can possibly convert
what is avowedly a disciplinary enactment, prohibiting the circulation
of certain books, into a dogmatic decree.

I should submit it to the judgment of theologians whether this would
not be true even if the Pope’s name had been explicitly introduced
as sanctioning the decree; as it stands, however, the decree appears
simply in the name of the Congregation of the Index.

It would, I think, scarcely be necessary to argue these points at
length, were it not that the contrary view has been maintained in a
work entitled “The Pontifical Decrees against the Doctrine of the
Earth’s Movement, and the Ultramontane Defence of them,” by the Rev.
William W. Roberts, a work written with ability and moderation as well
as considerable knowledge of the subject, since the author, though
determined to make all the controversial capital that is possible
out of the case of Galileo, rises superior to the vulgar atmosphere
of fable and false accusation; never alleges anything like personal
cruelty or ill-treatment as against the Pope or the Inquisition, and
scarcely alludes to the mythical story of “E pur si muove.”

Moreover, even were the intrinsic value of the work less than it is,
attention has been publicly drawn to it by a writer whom, both from a
religious and scientific point of view, we feel bound to treat with
respect--Professor Mivart--although he has formed, on the other hand,
an exaggerated estimate of the importance of Mr. Roberts’ facts and
arguments.

Here I wish to introduce an observation, as a sort of anticipatory
self-defence, which is that I do not feel bound to enter into all
the theological minutiæ which learned disputants have introduced
into this case. Those who wish to sift such arguments in detail can
read the articles in _The Dublin Review_ by the late Dr. Ward (since
republished) on the one hand, and Mr. Roberts’ book on the other. I
myself venture to look at the question as a lay theologian, employing
this expression not by any means in the sense of one who, having read
two or three theological treatises, presumes to discuss the sacred
science, himself an amateur, with men whose profession it is to teach
theology; for, to use a familiar expression, I hope I know my place
better. I employ the word in the sense of a man who seeks to know what
the Church teaches as requisite for a layman, that is an _educated_
layman, to understand: thus the lay theologian, as I consider him,
ought to be able to discriminate between what the Church teaches him as
matter of faith and what she enjoins or encourages him to hold under
a less solemn sanction. He ought also to distinguish clearly between
matters laid down by the Church as parts of her definitive teaching
both on faith and morals--points, that is to say, laid down as of
_principle_, and therefore irrevocable--and on the other hand matters
of discipline which, whether intrinsically important or not, may and
do vary from age to age. He may of course make mistakes, as even
theologians may do, in applying his principles to particular cases; but
he ought to understand what the principles are.

Now applying such plain principles to the Galileo case, I do not
understand how any one can come to any other conclusions than these:
first, that the decree of the Index and the other proceedings in
1616, though founded on reasons of doctrine, that is of the correct
interpretation of Scripture, were purely disciplinary in their
nature; secondly, that this being so, they were not infallible or
_irreformable_, as the term is; thirdly, that they were, however,
real acts of discipline, and intended to be enforced more or less
stringently according to circumstances. This last-named aspect of the
case is a matter of importance, and I shall return to it hereafter;
but the attempt to impugn the doctrinal infallibility of the Catholic
Church on the strength of such decisions as that of the Index in 1616,
seems to me so groundless that I should not discuss the question
further were it not that I think it right to notice some of Mr.
Roberts’ arguments.

It appears that certain theologians have held that decrees of the
Roman Congregations are to be considered infallible, provided they
contain a statement in so many words that the Pope has approved them,
and provided also that they have been published by his explicit order.
This, it may be mentioned, does not necessarily imply that such decrees
concern matters which are strictly and technically matters of _faith_,
other less momentous issues being frequently involved.

The decree of the Index in 1616 had no such statement about the Pope’s
approbation, nor any notice of his express order for its publication,
although, in reality, it was undoubtedly approved by him. Mr. Roberts
argues that this distinction is a worthless one, because, at that time,
the custom, since adopted on certain important occasions, of bringing
in the Pope’s name and authority explicitly, had not come into being.

As an _argumentum ad hominem_ against certain writers who have
suggested that such an omission in the Galileo case was a remarkable
instance of Divine Providence, Mr. Roberts’ answer may stand; but it
has nothing to do with the main argument. It only shows that whereas
the Popes of more modern times have employed the Roman Congregations
as instruments for conveying to the world their own decrees on certain
doctrinal subjects, the Popes of the early part of the seventeenth
century had no such custom. They used the Congregations for various
disciplinary purposes, founded sometimes, no doubt, on reasons of
doctrine, and they sanctioned the proceedings so taken; but they did
not give them the explicit impress of their own name and authority.
Even when this latter has taken place, it is not every theologian who
holds that such decree is infallible. Cardinal Franzelin, a writer of
the highest authority, whose words I give in a note,[3] held that it
was not infallibly true, but only infallibly safe. His language is not
quite clear to the non-theological mind, but he probably meant that the
doctrine conveyed in such a decree was safe, so that it might certainly
be held without injury to any one’s faith, and that it was not safe to
reject it. But it is clear that he was not speaking of such decrees as
took place in the Galileo case, but only of those which bear on them
the marks of Papal authority in the strict sense.

His own words are pretty plain proof of this. They are extracted from
his work, “De Divina Traditione et Scriptura,” and follow the other
words to which I have alluded:

    Coroll. D. Auctoritas infallibilitatis et supremum magisterium
    Pontificis definientis omnino nihil unquam pertinuit ad causam
    Galilei Galilei, et ad ejurationem opinionis ipsi injunctam.
    Non solum enim nulla vel umbra definitionis Pontificiæ ibi
    intercessit, sed in toto illo decreto Cardinalium S. Officii,
    et in formula ejurationis ne nomen quidem Pontificis unquam
    sive directe sive indirecte pronuntiatum reperitur...
    pertinebat omnino ad _auctoritatem providentiæ ecclesiasticæ_
    cavere, ne quid detrimenti caperet interpretatio Scripturæ per
    conjecturas et hypotheses plerisque tum temporis visas minime
    verisimiles.

We are not, however, I think, obliged to endorse the opinion conveyed
in the last sentence that I have quoted, though certain theologians of
great weight have held that the ecclesiastical authorities of Galileo’s
day were only acting with proper prudence in the then existing state of
astronomical knowledge. I shall hereafter state why I feel it difficult
to follow their judgment.

But the words I have quoted from Cardinal Franzelin show plainly that
the decrees he had in his mind, when he wrote that they were infallibly
safe, were of a nature quite different from anything that took place
in the processes connected with Galileo; and although he alludes
principally to that which passed in 1633 before the Inquisition, he
appears to include the whole affair in the judgment he passes upon
it; indeed, the sentence of the tribunal in 1633, and the abjuration
enjoined upon Galileo at that time, were made to depend on the decree
of the Index in 1616, and the admonition then given to Galileo by
Cardinal Bellarmine. Cardinal Franzelin’s opinion, then, whatever
weight we may give to it, is clear enough.

I give one more extract from the work of this learned author on the
subject of the Pope’s infallibility, showing that he was of opinion
that doctrinal definitions must be clearly and unmistakably intended
as such, and must carry with them some manifest signs to that effect.

Extract from the same on the subject of the Pope’s infallibility, pp.
108 and 109:

    Neque enim _Cathedra Apostolica_ aliud est, quam supremum
    authenticum magisterium, cujus definitiva sententia doctrinalis
    obligat universam Ecclesiam ad consensum. Intentio hæc
    definiendi doctrinam seu docendi definitivâ sententiâ et
    auctoritate obligante universam Ecclesiam ad consensum debet
    esse manifesta et cognoscibilis claris indiciis.

In the case we have before us, I should say that the “clara indicia”
were all the other way; and indeed, were it not for the dust which
controversialists have tried to throw in our eyes, I should be disposed
to add that we might fairly drop this part of our subject--I mean the
part which raises the question whether there was not some decision or
definition, such as Catholics are bound by their principles to admit as
infallible, given against the Copernican doctrine.

It is right, however, to notice one or two other arguments urged by Mr.
Roberts.

Some of these consist in bringing forward supposed parallel cases, in
which the Pope has insisted on a full and complete assent being given
to the decision of some Roman Congregation. One case is that of a
“distinguished theologian and philosopher, Günther,” whose works were
condemned by a decree of the Index, having, however, the notice that
the Pope had ratified the decision and ordered its publication. This
was in 1857. Günther and many of his followers submitted, but others
contended that a merely disciplinary decree was not conclusive. On this
Pope Pius IX. addressed a brief to the Archbishop of Cologne, in which
he intimated that a decree sanctioned by his authority and published by
his order should have been sufficient to close the question, that the
doctrine taught by Günther could not be held to be true, and that it
was not permitted to any one to defend it from that time forward.

I extract the words as given by Mr. Roberts:

    Quod quidem Decretum [that of the Index] Nostra Auctoritate
    sancitum Nostroque jussu vulgatum, sufficere plane debebat,
    ut questio omnis penitus dirempta censeretur, et omnes qui
    Catholico gloriantur nomine clare aperteque intelligerent
    sibi esse omnino obtemperandum, et sinceram haberi non posse
    doctrinam Güntharianis libris contentam, ac nemini deinceps
    fas esse doctrinam iis libris traditam tueri ac propugnare, et
    illos libros sine debita facultate legere ac retinere.

Mr. Roberts, it must be remembered, is not simply investigating the
history of Galileo, but is contending, for other reasons, against
certain opinions on the subject of Papal infallibility held by an able
foreign theologian, M. Bouix, and by Dr. Ward, and he uses Galileo as
a weapon (and, in his estimation, a most formidable weapon) in the
controversy. Now, in the capacity I have assumed of a _lay theologian_,
I do not feel bound to discuss whether the decree in Günther’s case
was merely disciplinary, or whether it was dogmatic; whether it came
within the category of strictly infallible pronouncements, or whether
it did not; and supposing the former alternative, whether it was
infallible in virtue of the Pope’s sanction and command to publish
in the first instance, or whether it only became so in virtue of the
brief addressed to the Archbishop of Cologne. All these questions,
interesting in themselves, I feel myself at liberty to pass over,
and to leave them, with the most profound respect, to be sifted by
professed theologians; I merely venture to remark, without attempting
to argue the matter, that, to my uninstructed intelligence, the whole
thing, including the Pope’s brief, appears to have a disciplinary
character rather than anything else.

What, however, I would say is this--the questions above mentioned,
which in the Günther case are doubtful, are in that of Galileo clear
enough; the clause stating that the Pope had sanctioned the decree, and
ordered it to be published, on which the doubt alluded to is founded,
did not appear in the decree against the Copernican books; nor did the
Popes of that day issue any brief, such as Pius IX. addressed to the
Archbishop of Cologne.

Mr. Roberts, it is true, thinks he has a clenching argument in a Bull
of Pope Alexander VII., of which I will speak hereafter, and which in
my humble judgment has the least force of any that he has adduced.

The case of Professor Ubaghs, of the University of Louvain, which Mr.
Roberts thinks still more to the point, seems, I confess, to me even
weaker than the other for our present purpose. Here, again, I leave it
to theologians to decide whether the decree was or was not infallible;
but it undoubtedly appears, in point of form, to be a doctrinal
one, and emanated from the United Congregations of the Index and
Inquisition, to whom the Pope had expressly entrusted the examination
of the subject, and it was as follows: “Wherefore the most eminent
cardinals have arrived at this opinion: that in the philosophical
works, hitherto published by G. C. Ubaghs, and especially in his Logic
and Theodicea, doctrines or opinions are found that cannot be taught
without danger” (_inveniri doctrinas seu opiniones, quæ absque periculo
tradi non possunt_). “Which judgment our most Holy Lord Pope Pius IX.
has ratified and confirmed by his supreme authority.” Even then some
persons maintained that the decree was disciplinary and not doctrinal.
Cardinal Patrizi, however, writing in the Pope’s name to the Primate
of Belgium (if I mistake not), intimated that the dissentients must
acquiesce _ex animo_ in the judgment of the Apostolic See. Consequently
all the professors who had committed themselves to the proscribed
opinions were required to make an act of submission to the effect just
mentioned. The decree was treated as strictly doctrinal, and if so was,
I maintain, essentially different from the one we have now before us.

In the case of Galileo, it is true that the opinion given in 1616 by
the Qualifiers of the Inquisition was a doctrinal one; the action
taken upon the strength of that opinion by the Pope in desiring
Cardinal Bellarmine to admonish Galileo, as well as by the Congregation
of the Index in prohibiting certain books, was simply disciplinary.[5]

It remains for us to inquire what was the value of the decree of the
Index on certain works, written in favour of the new astronomical
doctrines, as appreciated by _contemporary_ feeling and opinion. We
naturally find that there were two views on the subject: one of those
who wished to magnify the effect of the decision, and one of those who
desired to minimise it.

Galileo himself said that his opinion had not been accepted by the
Church, which, however, had only declared that it was not in conformity
with Holy Scripture; from which it followed that only books attempting
_ex professo_ to prove that the opinion is not contrary to Scripture
were prohibited. Whether Galileo was right or wrong in his estimate of
the scope of the decree, it seems evident that he considered the whole
matter as a question merely of discipline.

It is said that Father Melchior Inchofer, S.J. (afterwards one of the
Consultors of the Holy Office), endeavoured to prove that the decision
proceeded from the Pope speaking _ex cathedrâ_. Mr. Roberts gives a
quotation to that effect from a work of Professor Berti; the original,
however, does not appear, and is probably not now extant.

Mr. Roberts also quotes Caramuel, “the acute casuist,” who, in answer
to the supposed objection that the Copernican theory might hereafter
be shown to be true, says that it is impossible that the Earth should
hereafter be proved demonstratively to be in motion; if such an
impossibility be admitted, other impossible and absurd things would
follow.

Caramuel, however great as a theologian, was evidently not endowed with
much scientific foresight. But he is not wholly wrong, for it has never
yet been possible to prove by _absolute demonstration_ the motion of
the Earth.

One of the most important witnesses on the point we are here
considering is Cardinal Bellarmine, who was a very zealous
anti-Copernican, and had probably a great share (perhaps the principal
share) in bringing about the practical condemnation of Galileo’s
opinions in 1616. So far as I know, the only explicit statement bearing
on the question that we have of Bellarmine’s, is a letter to the
Carmelite Father Foscarini, dated April 1, 1615, though he has been
quoted as if he had expressed the opinion stated in the letter at a
later date. Mr. Roberts takes exception to the inference drawn from
this letter because it was written before the decree of the Index,
and we may add, about seven months before the referring of Galileo’s
writings to the Consultors of the Inquisition.

Now we may admit that there would be some force in this argument if
Cardinal Bellarmine, instead of being what he was, had been a private
individual, having nothing to do but to listen submissively to what his
ecclesiastical superiors decided, whether in doctrine or discipline.
He was, however, one of the most trusted advisers of the Pope; he had
no small share in bringing about the censure of the Copernican theory,
such as it was; and it is almost certain that at the time when he
wrote the letter he foresaw that some proceedings of that nature would
follow, if indeed the proceedings had not already begun. We have no
sort of intimation that he ever afterwards changed his opinion, and
the way in which he was quoted by subsequent writers points to this
conclusion. I have thought it better to answer the objection made by
Mr. Roberts before stating what Bellarmine’s letter contains. I must
leave my readers to judge the value of the argument. All I say is,
that my own belief is that Cardinal Bellarmine’s opinion, as recorded
in this letter to Father Foscarini, represents his permanent judgment.
It is a most curious letter, and is a singular illustration of the
danger that a man, however able and learned, may incur by attempting to
grapple with subjects of which he knows absolutely nothing. Bellarmine,
when writing on theological or controversial subjects, though he might
make an occasional mistake, was one of the clearest, ablest, and (may
one not add?) fairest of writers; but on a subject such as this, some
of his reasoning strikes us as very curious.

The substance of it is as follows: After admitting that so long as the
Copernican doctrine is stated hypothetically, “_ex suppositione_,”
there is no objection whatever to it, he goes on to say that to
state it positively and as a reality is contrary to the principle
laid down by the Council (_i.e._ of Trent), that Scripture should
not be interpreted contrary to the common consent of the Fathers;
and, he added, not only that, but the universal opinions of modern
commentators. In answer to the objection that it is not a matter of
faith, he says: “if it is not so _ex parte objecti_, it is so _ex
parte dicentis_,” meaning apparently that a man who impugned the truth
of the Scriptural narrative in any respect would be heretical. Then
follows the paragraph which has given occasion to quote the letter,
and it is to this effect:[6] When there shall be a real demonstration
that the Sun stands in the centre of the universe, and that the Earth
revolves round it, it will then be necessary to proceed with great
consideration in explaining those passages of Scripture which seem to
be contrary to it, and rather to say that we do not understand them,
than say that a thing which is demonstrated is false. But for his own
part, until it had been shown to him, he would not believe there could
be any such demonstration, for it was one thing to prove that if the
hypothesis were true all things would appear as they actually do, and
another thing to prove that such is actually the fact; and in case of
doubt one ought not to leave the interpretation of Scripture as given
by the Fathers. Then comes what is really an extraordinary argument, as
we modern thinkers would view it. The text, “The sun arises and sets,
and returns to his own place,” was written by Solomon, who was not only
inspired by God, but was also the wisest and most learned of mankind
in human sciences, and in the knowledge of created things, and it was
not likely he could be wrong. Nor was it sufficient to say that Solomon
speaks according to appearances; for though in some cases erroneous
impressions, arising from appearances, can be corrected by observation
and experience, it is quite otherwise as regards the motion of the
Earth.

It is certainly remarkable that it does not appear to strike Bellarmine
that the Fathers and commentators, not having this question before
them, naturally interpreted Scripture according to the ideas generally
entertained in their day. While to suppose that, because Solomon wrote
certain inspired works, and, moreover, was a great naturalist--the
greatest of his day--he was, therefore, infallible in his personal
views on astronomy, shows a state of mind so different from what we
find amongst even non-scientific men in our own day, that we are
almost startled and bewildered when we meet with it. The truth,
however, is that Bellarmine was a sort of link between the mediæval
and modern thinkers; in theology and controversy, and in appreciation
of the change that had taken place in Europe owing to the religious
revolution of the preceding century, in all that, he was, I imagine, in
advance of his age; in physical science he was a simple mediævalist.
But it was not for some time that even able men came to recognise the
principle that in the search for truth, so far as the works of Nature
are concerned, the opinions of the ancients and the traditions of
forefathers count but for little; and observation and experiment are
the true and only key to knowledge. It is otherwise, of course, with
theology and kindred studies; and it required some mental grasp, or in
default of that it required a long, very long, experience before the
human mind drew the distinction between the two.

But this is a digression. I have quoted Bellarmine to show what he
thought of the necessity, from an ecclesiastical standpoint, of
putting down Copernicanism, at least until it should be proved to
demonstration. He did not appear to contemplate a dogmatic decision
against it, but what he did desire, and succeeded in obtaining, was a
disciplinary prohibition of the obnoxious doctrine. As a theologian
he well knew that such a prohibition would not be an irrevocable act;
it might be withdrawn when the conclusive proof of the forbidden
opinion should be established. He probably thought that the certain
demonstration of the opinion would only take place, as mathematicians
would say, at an infinitely distant date; nor was he wholly wrong,
as has already been remarked, for the absolute demonstration of the
Copernican doctrine is not, from the very nature of the case, a thing
to be achieved.

Yet, if he had lived at a later period, I do not doubt that he would
have been satisfied with the moral evidence, the mass of indirect
proof, on which Copernicanism rests. Many years later, the Jesuit
Father Fabri, who appears to have held the office of Canon Penitentiary
of St. Peter’s, expresses himself in much the same way as Bellarmine.
He was replying to the arguments of some Copernican correspondent,
possibly an Englishman, since his reply was inserted in the Acts of the
English Royal Society in 1665, and he says: “There is no reason why
the Church should not understand those texts in their literal sense,
and declare that they should be so understood so long as there is no
demonstration to prove the contrary. But if any such demonstration
hereafter be devised by your party (which I do not at all expect), in
that case the Church will not at all hesitate to set forth that those
texts are to be understood in an improper--_i.e._, non-literal--and
figurative sense, according to the words of the poet, ‘terræque
urbesque recedunt.’”

As a further illustration of the position thus taken by Bellarmine
and others as to the interpretation of Scripture, I may here mention
that some few years after the prohibition of Copernican works by
the Index (probably about 1623), it is said that Guidacci had an
interview with Father Grassi, at the suggestion of the Jesuit Father
Tarquinio Galluzzi, and that F. Grassi’s words were as follows: “When a
demonstration of this movement [that of the Earth] shall be discovered,
it will be fitting to interpret Scripture otherwise than has hitherto
been done: this is the opinion of Cardinal Bellarmine.” It is not
intended to deny that there were those who magnified the effect of the
decree of the Index; the devotees of Aristotle, who had gained what was
to them a great triumph, were sure to make the most of it.




CHAPTER III.


We will now return to the narrative; and in due course discuss the
condemnation of Galileo by the Inquisition sixteen years after the
events just described.

It may be mentioned, as illustrating the feeling in Rome towards
Galileo personally, that on the 11th March, 1616, he had an audience,
lasting three-quarters of an hour, of Pope Paul V. He assured the Pope
of the rectitude of his intentions, and complained of the persecutions
of his adversaries. Paul V. answered very kindly, saying that both
himself and the Cardinals of the Index had formed a high personal
opinion of him, and did not believe his calumniators.

In the year 1620 there appeared a monitum of the Congregation of the
Index, permitting the reading of the great work of Copernicus after
certain specified corrections had been made.

Not long after this, in 1622, if I mistake not, Pope Paul V. died, and
Galileo’s friend, Cardinal Barberini, succeeded him, taking the name
of Urban VIII. Another of his friends, Monsignor Ciampoli, became
secretary of briefs to the new Pope.

Our philosopher having ascertained that he would be well received,
went to Rome in April, 1624, and was treated by the new Pope with
all possible consideration. He had, in fact, several conversations
with him; and we may well conjecture it was on these occasions that
Urban VIII., discussing the Copernican theory, used some of those
arguments which Galileo afterwards put in the mouth of Simplicio in his
celebrated Dialogue, thereby deeply offending the Pope.

But there was, about this time, a sort of moderate reaction in favour
of Galileo among the authorities at Rome. For instance, a work of his
published since the decree of the Index, and entitled “Il Saggiatore,”
in which he had favoured the theory of the Earth’s motion, was
attacked, and an attempt was made to have it prohibited or at least
corrected, but the attempt was a failure.

The reports of casual or unofficial conversations are always to be
received with caution and with some qualification; yet at least they
are “straws which show how the wind blows.”

Thus we are told that Cardinal Hohen-Zollern, in a conversation with
the Pope (Urban VIII.) on the subject of Copernicus, endeavoured to
show the necessity of proceeding with great circumspection on that
point, to which it is said the Pope replied that the Church had not
condemned and would not condemn that opinion as heretical, but only as
temerarious. So again the Master of the Sacred Palace, himself resting
neutral between Ptolemy and Copernicus, is reported to have said that
there was no matter of faith in question, the great point being that
one must not in any way mix up the Holy Scriptures with it.

We may suppose that when the Pope spoke of the opinion having been
condemned as temerarious, what he meant was not that it had been
explicitly censured as such--using the word in the technical sense
which it bears when applied as a censure--for that it plainly had not
been, but that the general effect of the prohibition issued by the
Index was to stamp the mark of rashness upon it. This, I may observe,
if it be the right interpretation, is quite consistent with the theory
that the prohibition was of a disciplinary and a provisional character.

We have also another reputed conversation of the Pope with
Campanella--resting on the authority of Prince Cesi, who related it to
Father Castelli--and it is important if true. Campanella had said that
certain Germans, ready to embrace the Catholic faith, had hesitated on
account of the condemnation of Copernicus, to which Pope Urban VIII.
had replied that this was not his intention, and if he had had the
arrangement of matters the decree would never have been made. “Non fu
mai nostra intenzione, e se fosse toccato a noi, non si sarebbe fatto
quel decreto.”

As already remarked, we must not attach too great weight to reports
of private conversations; but it is probable that some such scene
took place as here represented, and, if it did, it is surely wholly
incompatible with the idea that the decree was a decision in matters
of faith. No Pope, no well-informed ecclesiastic of any rank, would
express himself so in such a case; but it is quite consistent with what
we might expect in a question of simple discipline.

It will now be convenient, before discussing the matter further, to
resume the narrative, and to touch upon the questions connected with
the condemnation of Galileo by the Inquisition, and his enforced
abjuration. It is, indeed, these latter proceedings that have left so
deep an impression upon the popular mind, though, strictly speaking,
they were of less importance than the decree of the Index--of less
importance, that is, to all others besides Galileo himself.

It seems that our philosopher overrated the effect of the reaction that
had taken place in his favour, real though it was so far as it went.
He thought he might now safely publish the work on which he had been
labouring, and on which he probably relied as likely to influence the
minds of learned men, ecclesiastical as well as lay, in the direction
of Copernicanism.

He came in May in the year 1630 to Rome, and had a very long audience
with the Pope, who treated him with great kindness and even increased
a pension he had already bestowed upon him; but we do not know what
passed as to other matters on this occasion. He had also an interview
with Father Riccardi, who had now become Master of the Sacred Palace,
with a view of obtaining authority to print his book. Father Riccardi
upon this engaged Father Visconti, who was a professor of mathematics,
to read the work and mark such passages as he thought necessary.

Father Visconti reported that there were some passages which required
correction, and many points that he would like to discuss with the
author. However, the Master of the Sacred Palace gave leave for the
printing of the work, expressing at the same time a wish to see it once
more himself; consequently it was arranged that Galileo should return
to Rome in the autumn, in order to add the preface, and to insert in
the body of the work certain passages, calculated to show that the
question was being treated purely as a hypothesis.

Two untoward events, however, now occurred: one was the death of Prince
Cesi, a powerful and devoted friend of Galileo, which took place on
the 1st May; and the other was the outbreak of the plague at Florence,
a circumstance which interrupted communications, and caused delays
resulting in mistakes and misunderstandings. With a view of having
the Dialogue printed at Florence, it was arranged that the revision
required by the ecclesiastical authorities should take place there
instead of at Rome. Father Hyacinthe Stephani, a Dominican, who acted
as reviser, marked several passages in the work, thinking that they
should be explained before the final permission for publication was
conceded.

Then followed mutual delays: the author was tardy in sending to Rome
the corrections to which he had in principle agreed, and the Master of
the Sacred Palace was late in sending to Florence the preface and the
conclusion, so the impatient philosopher began to print his book. The
plague still continued, and the result was that communications were
still interrupted.

The Inquisitor of Florence however received from Rome the power to
approve officially the copy of Galileo’s work that would be submitted
to him, with instructions specially added by Father Riccardi that he
must bear in mind the wishes of the Pope to the following effect:
The title of the work must indicate that it dealt only with the
mathematical question connected with Copernicanism, also that the
Copernican opinion must not be put forward as a positive truth, but
merely as a hypothesis, and this without alluding to the interpretation
of Scripture; moreover, that it should be stated that the work was only
written to show that if the decree (_i.e._ of 1616) was made at Rome,
nevertheless the authorities knew all the reasons against it that could
be urged, and were not ignorant of one of them--an idea conformable to
the words of the preface and the conclusion, which he would send from
Rome corrected. With this precaution, it was intimated the book would
meet with no obstacle at Rome, and thus satisfaction might be given
to the author, and also to the Grand Duke of Tuscany, who had shown
himself to be so eager in the matter.

This remarkable letter points towards a conclusion which has been
drawn by some writers, that the preface to the Dialogue was written for
Galileo by Father Riccardi or some other person, and was not his own
composition; for the above is precisely what was said in the preface
as it afterwards appeared, and it seems to me almost incredible that
Galileo should have spontaneously written any such words, exposing him
to the charge, which has really been made against him, of transparent
irony, thereby giving offence in the very quarters where conciliation
was desirable.

And it must be remarked that when Father Riccardi on the 19th July of
this year sent the preface to Florence, he allowed Galileo the liberty
of making verbal alterations only; so that whether he composed it or
only revised it, it is Father Riccardi rather than the author of the
Dialogue who must be held responsible for the contents, and the same
remark applies at least partially to the conclusion also, it having
been specially revised by the same hand.

The preface is addressed to the discreet reader, and the words to
which I have just alluded are as follows: “Some years ago, a wholesome
edict was promulgated in Rome which, in order to check the dangerous
scandals of the present age, imposed an opportune silence upon the
Pythagorean opinion of the motion of the earth. There were not wanting
some who rashly asserted that that decree resulted, not from judicious
examination, but from ill-informed passion; and there were heard
complaints that Consultors, wholly inexperienced in astronomical
observations, ought not to be allowed, with a hasty prohibition, to
clip the wings of speculative intellects. My zeal could not keep
silence on hearing the temerity of the complaints so made. As one fully
informed of that most prudent decision, I judged it right to appear
publicly in the theatre of the world, as a witness of pure truth. I
happened then to be present in Rome; I had not only audiences, but
approbations from the most eminent prelates of that Court, and it was
not without my own previous information that the publication of that
decree then followed.” The author goes on to say that he wished to
show to foreign nations how much was known in Italy, and particularly
in Rome, on this subject; and that from this climate there proceed not
only dogmas for the salvation of the soul, but ingenious devices for
the delight of the mind.

This last clause certainly savours of bitter irony, and probably did
not proceed from Father Riccardi’s pen. He then states that for the
purpose in hand he had taken the Copernican part in the Dialogue
as a pure mathematical hypothesis, endeavouring by every artifice
to represent it as superior, not to that of the stability of the
Earth absolutely speaking, but to the doctrine as defended by the
Peripatetics, to whom he alludes with some contempt.

He adds that he will treat of three principal heads: under the first
he would show that all our experience was insufficient to prove
conclusively the motion of the Earth, but that it adapted itself
equally to either theory; he hoped also to produce many observations
unknown to antiquity. In the second place, the celestial phenomena
would be examined, by which the Copernican hypothesis would be so
reinforced as if it ought to come out of the contest absolutely
victorious. In the third place he would propound his theory about
the tides: “proporrò una fantasia ingegnosa,” he says. He had long
been of opinion that the unknown problem of the tides would receive
some light on the assumption of the Earth’s motion. Other persons had
adopted his statement on this point as if it had been their own; he
therefore thought it desirable to expound it himself. He hints, too,
that the willingness to admit the stability of the Earth, and to take
the contrary side solely for mathematical caprice, is partly based
on piety, religion, the knowledge of the Divine omnipotence, and the
consciousness of human weakness.

He had thought it well to cast these thoughts into the form of a
dialogue, which gave a certain amount of freedom to digressions.

He then introduces the personages who sustain the discussion, and who
are supposed to meet at Venice at the palace of one of their number,
Sagredo by name.

This preface, if one may judge by internal evidence, was probably the
joint composition of Galileo and Father Riccardi, the former having
written the original draft, the latter having altered the draft and
supplemented it with important additions.

The body of the Dialogue--which I suspect that many persons who
consider themselves competent to give an opinion on the Galileo
case have not so much as even seen--is divided into four portions,
each being supposed to be one day’s dialogue. The interlocutors are
Salviati, Sagredo, and Simplicio. Great offence was taken at the rôle
attributed to this last-named personage--the true doctrine put into the
mouth of a simpleton! It has been said that Pope Urban VIII. considered
it as an insult directed against himself, because, in conversation with
Galileo, he had used some of the very arguments employed by Simplicio.
This, however, may have happened without the author intending thereby
to offer any personal affront to His Holiness; some character was bound
to appear on the anti-Copernican side, and it was inevitable that the
arguments that Galileo had heard, whether from ignorant or enlightened
antagonists, should be put into the mouth of such character. The name
Simplicio is of course not meant as a compliment; moreover, he is made
to say some very unwise things, and is occasionally treated with a
sort of polite contempt by the scientific and mathematical Salviati;
and yet he is not at all a simpleton in our sense of the word, he is
a devoted follower of Aristotle, whom he constantly quotes, and is in
fact a type--probably exaggerated--of the school of the Peripatetics,
as they were, and still are, called; he does not know much of geometry
or arithmetic, and so is at no small disadvantage when arguing with
Salviati, but he is far from being a mere fool. Our author, in his
preface, introduces Salviati and Sagredo--the former a Florentine,
the latter a Venetian--as real personages, deceased friends of his
own, though this may be a mere conventional form of expression; but
he expressly states that Simplicio is not the true name of the “buon
Peripatetico.”

The friends are supposed to meet in the palace of Sagredo, at Venice,
as before stated.

The first day’s dialogue deals with a good deal of what one may term
preliminary matter: that bodies have three dimensions and no more; that
circular motion is the most perfect and the most natural; showing by
this that Galileo had not at that time arrived at a true comprehension
of the first law of motion, as we now hold it. The motion of weights
on an inclined plane finds also a place in the discussion; and so does
what we now term the law of accelerating force, which Galileo had
grasped so well as to be able to explain how the velocity increases by
infinitely small steps gradually, and not, as it were, by sudden jumps.

Much of the matter disputed on--as, for example, whether the heavenly
bodies being incorruptible differ in that respect from the Earth,
liable as it is to corruption and decay--which seems to us either
erroneous in conception or irrelevant to the question at issue, or
both--arose out of the old Aristotelian philosophy; and in those days a
dissertation which neglected points of this kind would have been looked
upon probably with contempt, as evading subjects that it ought to have
grappled with. The distinction between natural and artificial motion,
which occurs repeatedly in the Dialogue, is an instance of an utterly
mistaken notion, having its origin in Aristotle, who, great philosopher
though he was in other ways, failed in his investigations of physical
science, partly from being misled by verbal fallacies.[7]

Another point that our author endeavours to establish in the first
day’s dialogue is that the Moon is not a polished surface, as Simplicio
and others thought, but much like our own Earth, with mountains and
plains and seas--this last being a mistake, as subsequent observation
has shown. The solar spots are also discussed, and so, incidentally, is
the question whether the heavenly bodies are inhabited, the affirmative
opinion finding little favour with any one.

During the second day the great subject is the revolution of the Earth
on its axis; and Salviati urges forcibly the improbability of the
motion of the whole celestial sphere round the Earth in twenty-four
hours, including such a number of vast bodies, and with such an immense
velocity, while one single body (the Earth), turning round on itself,
would produce the same effect. He argues also that if you believe in
this motion of the celestial sphere, you must suppose the planets to
be moving in two opposite directions at the same time, the diurnal
one from east to west, and the annual one from west to east--using
the word _annual_ in its extended sense, as applied to the periodical
revolutions of all the planets. To this Simplicio makes the sapient
answer that Aristotle proves that circular motions are not contrary
to each other; upon which the third interlocutor, Sagredo, asks him
whether when two knights meet one another in the open field, or two
fleets at sea--in the latter case sinking each other--such motions
can be called contrary? This Simplicio is obliged to admit; he uses,
however, another argument, which did not seem so absurd in the then
existing state of science, namely, that there may be another sphere
beyond that of the stars, and itself starless, to which belongs the
property of the diurnal revolution, and that this sphere may carry
along with it the inferior spheres, these latter participating in its
movement. Ideas such as these were part of the pre-telescopic notions
of astronomy. Simplicio’s argument is in reply to some powerful reasons
drawn from the motions of the planets, the nearer revolving in a
shorter, and the more remote in a longer period; it being extremely
unlikely that they would be all whirled round the Earth in one day; and
also from considerations connected with the stars.

It took a long time to disabuse the human mind of the antiquated
opinion that the stars and planets were set in vast movable spheres, as
lamps might be set in a large revolving cupola.

One of the objections made at that time against the axial rotation of
the Earth was that, if it were really the case, any weight dropped from
a high tower would fall some way to the west of the tower, on account
of the latter having been carried on eastward by the revolution of the
Earth during the few seconds the weight takes in falling,[8] and that
such a result was contrary to experience. In those days, when even
the first law of motion had been barely guessed at, the second law,
that of the action of combined forces on any body, was of course not
generally understood; and a considerable debate as to this point occurs
in this same day’s dialogue. Simplicio has the hardihood to assert that
if a stone be let fall from the mast of a vessel, the vessel being in
motion, it falls behind the mast. Salviati, after making a foolish
distinction--in accordance, however, with the philosophical ideas then
prevalent--between the natural motion of the Earth on its axis, and
the artificial motion of the vessel, asks Simplicio if he has ever
tried the experiment, which, of course, he had not. He then tells him,
and most truly so, that the experiment, if made, would show a very
different result, and that the stone would fall at the foot of the
mast, whether the vessel were in motion or not. Further on, Simplicio
maintained that a projectile thrown from the hand, according to
Aristotle’s argument, is carried on by the air, itself set in motion by
the hand of the projector; and if the stone let fall from the mast of a
ship falls at the foot of the mast, it must be the effect of the air.
So again he imagines that a ball dropped from the hand of a man, riding
fast on horseback, falls some way behind, and does not partake of the
horse’s speed. Salviati, however, tells him that he deceives himself,
and that experience would teach him the contrary.

Various difficulties are discussed in this dialogue well known to the
disputants of that day. It being questioned why a projectile shot from
a gun point-blank towards the east does not fall above the mark aimed
at; or shot westwards fall below it? How it is that birds, when flying,
are not left behind by the revolving Earth, since they at any rate are
completely detached from the ground above which they are soaring? Why
it is that light objects do not fly off at a tangent?

One sees throughout the power of the master-mind of Galileo. He knew
many things in mechanics which no subsequent research or experiment
has ever corrected; but here and there, as may naturally be supposed,
he is at fault. It must ever be remembered that a dialogue, though
a convenient form of argument in some respects, does not always give
one a clear insight into the author’s real convictions. You are not
sure whether he quite agrees with any of the spokesmen, and, indeed,
Galileo, in his defence before the Inquisition, practically assumes
that he did not so agree. It is, however, a good form of discussion
for a man whose opinions are intended to be expressed in a _tentative_
shape, and perhaps Galileo’s mind was in a state congenial to such
expression. But, at any rate, it makes it rather more difficult to do
justice to the author, as one is never sure what he intends to be taken
as the expression of his own deliberate belief; indeed, whatever may
have been the amount of indecision in which in this case our author’s
mind was involved, it is scarcely possible, notwithstanding his
disclaimer, to ignore the fact of his strong Copernican opinions.

I think one may say that Galileo did not, at the time when he wrote
the dialogue, know the gravity of the air. I say at that time, because
it is quite possible that he knew it before his death, since he lived
some ten or twelve years after writing this work. It is maintained that
he knew it because there is extant a letter from Baliani, the date
of which I believe to be about 1631, in which the latter expresses
his acknowledgments to Galileo for having taught him this truth. May
it not, however, be that what is here meant is the _pressure_ of the
air? If any one thinks Galileo understood at that time the principle
of the gravity of the atmosphere, I refer him to the second day’s
dialogue. He was aware, no doubt, that the air was carried round by
the Earth in its diurnal motion, but why it was so carried round I do
not think he quite understood; indeed, as may well be supposed, he did
not _clearly_ understand what gravity was; it was a mysterious force,
drawing heavy bodies towards the centre of the Earth, a force to which
we, indeed, give the name of gravity, but of the essence of which we
know nothing, as, in fact, we know nothing of the nature of the force
that moves the heavenly bodies. This passage is remarkable because it
looks as if Galileo half suspected that the force which acted on the
Moon and the planets might be akin to that which attracted terrestrial
objects towards the centre of the Earth. If he really had arrived at
such a conclusion, he would have anticipated the great discovery made
thirty or forty years later. I think, however, that he only wished to
illustrate the one by the other, and that the allusion means no more.
I give, however, the passage in a note,[9] so that any reader may form
his own judgment; and I may add that according to an opinion commonly
held by the Copernican school of that age, the adherence of the
atmosphere to the Earth as it revolved was the effect of _friction_.

Our philosopher, wise as he was, had not freed himself from the
antiquated notion that some bodies were essentially heavy and others
light, which latter had no tendency to descend; not thereby meaning
comparatively light substances, but such as were absolutely free from
the action of gravity; the fact not being then understood that it is
only the resistance of the air that prevents the smallest feather from
falling to the ground as quickly as a cannon-shot.

Another mistake into which he falls is that of maintaining, in answer
to the argument that the diurnal rotation of the Earth would cause
objects to fly off from the surface at a tangent, that _no amount_ of
velocity of rotation would be sufficient for such a result to follow;
whereas, it is well known to modern students of mechanics that if a
certain very high velocity of rotation were reached, the centrifugal
force would overcome that of gravity, and objects would be projected
from the surface of the Earth in the direction of the tangent at that
point.

Some irrelevant arguments occur, of which, no doubt, many were
employed at that time on both sides; I think it was the late Professor
de Morgan who (in an article written for a popular periodical) made
a list of these; and it must in all fairness be said, that this
circumstance ought to be taken into account, as palliating the apparent
obstinacy of the anti-Copernican party in denying the motion of the
Earth. The argument drawn from the tides is, of course, the most
striking instance of these scientific fallacies; but it was by no means
the only one; in this particular dialogue there is another, which is
worth noticing because it confirms what I have just said as to Galileo
knowing nothing of the doctrine of universal gravitation. He puts
into the mouth of Salviati the argument that bodies which emit light,
as do the Sun and fixed stars, are essentially different from those
which, like the Earth and planets, have no such property--a distinction
which modern astronomy does not endorse--and that, as the Earth in
this respect resembles the planets, and the planets are undoubtedly
moving, so probably the Earth also is like them in motion, whilst the
Sun and the stars remain at rest. It is obvious that ideas of this
kind, however plausible they may seem, are utterly at variance with the
theory of universal gravitation, according to which, even if the Sun
were a dark, cold body and the Earth glowing with heat and light, the
Earth would revolve about the Sun just as it does now, _provided the
mass of the two bodies remained the same_ as at present.

Another suggestion, and a rather amusing one, on the opposition side,
was that all things in motion require occasional rest, as we see to
be the fact with animals; therefore the Earth, if it were constantly
moving, would stand in need of rest--an argument, I suppose, which
needs no very elaborate answer.

In the third day’s dialogue a question is raised, and sifted at
great length, as to whether a certain newly observed star in the
constellation Cassiopeia was in the firmament among the distant fixed
stars, or “sublunar,” _i.e._ nearer to the Earth than the Moon. This
star was probably the same as the very remarkable one first observed
by Tycho Brahé in 1572, which attained a brilliancy so extraordinary,
that it is said to have been equal to the planet Venus, and to have
been visible to good eyes in full daylight; in about a month’s time it
appeared to grow smaller, and gradually faded away until it disappeared
entirely--about six months after it was first discovered. This was some
years before the invention of the telescope, and the observations were
deprived of any assistance they might have gained from that source. The
star was one of the most noteworthy of all the variable stars on record.

There followed upon the mention of this star, a dissertation on the
method of finding the distances of the heavenly bodies by parallax. The
principle of this method was, as we may suppose, well known to Galileo;
but he probably did not allow _sufficiently_ for the great difficulty
in taking accurate observations, especially with the imperfect
instruments then in use; I say sufficiently, because that there were
such errors he knew, and he insists on the fact in the Dialogue.

Much discourse is spent on the distance of this new star; the
apparent reason of which is that it had created some sensation among
the astronomers of that day, and therefore the subject received an
attention out of proportion to its real importance--I mean importance
so far as the Copernican controversy was concerned.

The conversation is then brought back to the objections made by
contemporary philosophers to the Copernican system. Aristotle’s idea
of the universe was that of a vast sphere, or number of concentric
hollow spheres, with the Earth in the centre; if that were shown to be
probably untrue, his system broke down.[10] Coming, however, to our own
immediate portion of the universe, the question is now raised whether
the Earth or the Sun is the centre of revolution. Galileo, by the mouth
of Salviati, explains forcibly the argument for the Sun being so. That
Mercury and Venus revolve round the Sun he takes for certain; the
phases of Venus, which he had himself observed, proved it as regards
that planet; and the fact of neither of these bodies ever being seen
far apart from the Sun, greatly strengthened the conclusion in respect
of both of them. A transit of Mercury over the Sun’s disc had, in fact,
been observed in the year 1631, by Gassendi; but Galileo was doubtless
not aware of it when he wrote the Dialogue.

It being clear then that Venus and Mercury revolve round the Sun,
Galileo shows what strong ground there is for inferring that the
superior planets, Mars, Jupiter, and Saturn (the others not being then
known), do so also; this he judges from the greater size of these
latter, and particularly of Mars, when in opposition than when in
conjunction; whence we may conclude that the Earth, which as well as
the Sun is contained within their orbits, is not in the centre of them,
or nearly so. It is remarkable that Galileo treats all the planets as
revolving in _circles_, though one would think he must at that time
have been aware of Kepler’s discovery--that they move in _ellipses_. He
makes Simplicio grant these last-mentioned points, which is curious;
and he also explains how the telescope showed phenomena, such as the
phases of Venus, which were unknown to Copernicus. Simplicio has
hitherto had no confidence in this new instrument, and following in the
footsteps of his friends the Peripatetic philosophers, has supposed the
appearances in question to be optical illusions arising from the lenses
used; he will, however, gladly be corrected if in error. Simplicio’s
mathematical acquirements are not very great, and it is necessary to
explain to him that the areas of circles vary in proportion, not to
their diameters simply but to the squares of the diameters, a point
which arises in reference to the false judgment formed by the naked eye
as to the size of the celestial bodies, an error which is corrected
by the telescope. Then to those who made it a difficulty that the
Earth should move round the Sun, not alone, but accompanied by the
Moon, Salviati is made to reply that Jupiter revolves round the Sun
accompanied by four moons.

Again the greater simplicity of the Copernican theory, in accounting
for the planetary motions, as they appear to us, is expounded by the
same personage.

Galileo occasionally makes the interlocutors allude to himself as “il
nostro amico comune,” “il nostro Accademico Linceo,” etc., and thus
claims credit for having been the first to discover the solar spots, a
credit which ought not to belong exclusively to him, as Fabricius and
the Jesuit Father Scheiner saw the spots at about the same time.

An argument is here attempted to be drawn in favour of the Earth’s
annual motion from the apparent course of the Sun-spots, and the
curves they sometimes describe (as viewed from hence), owing to the
inclination of the Sun’s axis to an axis perpendicular to the plane of
the ecliptic--an inclination of about 7°; there is nothing, however, at
all conclusive in such argument, because the appearances in question
result from the different _relative_ positions of the Earth and Sun at
different seasons of the year, and would be the same whichever of the
two bodies were in motion.

There follows some conversation arising from one of the anti-Copernican
books of that day; one of the difficulties suggested, being the vast
distance at which you must suppose the fixed stars to be placed, if
Copernicus be right. We who are accustomed to the idea of these immense
distances, can scarcely understand the prejudices of the philosophers
of that age against admitting them. And it is worth noting that Galileo
takes for granted, while answering these theoretical objections, the
calculation of his predecessors--that the distance of the Sun is that
of 1,208 semi-diameters of the Earth, that is something more than
4,800,000 miles, about one-nineteenth part of what we now know it to
be. So also he supposes the size of the Sun to be much less than what
is really the case. He was also under the erroneous impression, arising
doubtless from the imperfection of the instruments he used, that the
stars really had an apparent diameter, though less than Tycho Brahé and
other astronomers had supposed, and estimates the angular diameter of a
star of the first magnitude at about 5″; consequently he imagined the
stars to be much nearer than is actually the fact. It is well known to
modern observers, that the apparent size of a star is the effect of an
optical illusion, and that greatly as the stars vary in brightness,
they present no appreciable diameter at all to the eye; not even those
classed as being of the first magnitude.

Another and more weighty objection to Copernicus is, however, urged by
the mouth of Simplicio, and it is this--if the Earth really makes an
annual revolution round the Sun, why do not the fixed stars, viewed as
they must be at different seasons of the year from points so widely
distant, change their apparent positions in the heavens? We have just
seen that the true distance of the Sun was not known at that time;--if
it had been known, and if the men of that age had been aware that the
diameter of the Earth’s orbit was about 184,000,000 miles in length,
the objection would have been still more forcible. But the modern
answer to it is conclusive: the stars, or rather a certain number
of them, do actually undergo a small displacement in their apparent
position every year, or in the technical language of astronomy, they
have an annual parallax, a fact which not merely disposes of the
objection, but actually confirms the truth of the Copernican theory.

Galileo’s reply (by the mouth of Salviati) is to the effect that
the followers of Ptolemy admit that it takes 36,000 years to effect
a complete revolution of the starry sphere; then, judging from the
planets, the length of time required for the orbit is in proportion
to the distance, and we suppose the distance of the starry sphere to
be, on such assumption, 10,800 semi-diameters of the Earth’s orbit (or
Sun’s orbit, as they called it). At so great a distance as that, the
change of position caused by the Earth’s annual motion round the Sun
would not be appreciable.

The principle of this reply is of course quite sound, and we, who know
the stars to be considerably farther from us than the above estimate
supposes, can well understand that the vast majority of them have no
annual parallax whatever, that the finest instruments can discover.

To further objections drawn from the enormous distances of the stars,
and the difficulty of perceiving the use which such remote bodies can
be to the Earth, it is replied that such speculations are useless and
presumptuous, and also that words like small, very small, immense,
etc., are relative rather than absolute.

Some pains are taken in the course of the dialogue to explain how the
stars, according to their different positions, would be affected by
annual parallax, supposing such to be discoverable, and assuming the
motion of the Earth. And a minute explanation is also given, on this
latter assumption, of the length of day and night varying in different
latitudes according to the seasons; illustrating the fact that details
which appear to us elementary and are taught to schoolboys, were
strange to the minds even of educated and learned men in those days.

One remark, arising from the questions connected with stellar parallax,
is most striking, as showing how far Galileo was advanced in his
knowledge of pure mathematics as well as of mechanics and astronomy.
Salviati is made to say that the circumference of an infinite circle
is identical with a straight line: “sono l’istessa cosa.” This idea,
familiar though it be to modern mathematicians, is one that we
should not have expected to find enunciated in the early part of the
seventeenth century; even the intelligent Sagredo cannot understand or
believe it, and it is not further discussed; but the fact of its being
here stated is especially noteworthy.[11]

Another (less felicitous) guess is hazarded by the same interlocutor
Salviati, who, as I have already remarked, appears to be the one that
most nearly represents the author’s own mind,--to account for the
Earth keeping her axis pointed (approximately, that is to say) in the
same direction during each annual revolution round the Sun. Salviati
suggests that it may be due to some magnetic influence, and that the
interior of the Earth may be a vast loadstone. This is strange, because
it is evident from what immediately preceded, that the author was aware
of the true reason, which in fact he illustrates by the well-known
experiment of a light ball floating in a bucket of water, to which a
revolving motion is imparted. It seems, however, that a work by William
Gilbert on the subject of magnetism had had some influence on the
scientific thought of the period, and that Galileo had considered it
worthy of his attention. The writer had maintained the probability of
this theory, of the Earth’s interior being an enormous loadstone--not
an unnatural idea in the then-existing state of science--and Galileo
was evidently somewhat fascinated by the hypothesis. Magnetism was
attracting the notice of the philosophers of that day, and the property
of the needle, which is termed the _dip_, had been recently discovered.

There is not much else worthy of special mention in the third day’s
dialogue; which in fact, as a whole, is not equal to that of the second
day.

The fourth day is mainly devoted to the argument drawn from the tides.
It was in handling this branch of the subject that Galileo’s great
sagacity and power of discernment seem to have deserted him. It is a
curious thing that the inhabitant of a Mediterranean country, who, for
all that one knows, never saw a really great tide in his life, should
have seized upon this topic, and so utterly misused and perverted it.

If, instead of living in Italy, he had resided at an English seaport,
he would probably have never fallen into the mistakes he thus made. In
the Mediterranean there are currents, arising from other causes, which
he, however, attributed to tidal action; but for the most part there
is little, if any, appreciable ebb and flow of the tides, scarcely any
perceptible rise and fall of the sea, a fact which he particularly
notices. But in some few places, and notably at Venice, there is
a sensible tide, so it is said, causing a difference of a few feet
between high and low water.

Now Galileo was under the impression that the ebb and flow took each
about six hours, following the ordinary solar day; whereas, if he had
observed the phenomenon on the shores of any sea, where the tidal wave
of the ocean made its full force to be felt, or again, at the mouth of
a great tidal river, he never could have failed to perceive that the
rise and fall of the water follow approximately the _lunar_, and not
the solar day, the former being fifty minutes longer than the latter.
It must of course be understood that the theory of the tides was first
investigated fully and scientifically by the same great genius to whom
we owe the theory of universal gravitation; and Galileo, who lived
half a century earlier, may well be excused for not having grasped
it. But it had long been known that the Sun and Moon had an influence
upon the tides, and as I have just stated, any one who watched the
movements of the sea from day to day, and from week to week, at a place
where there is a great rise and fall--as for instance, in the Bristol
Channel--could not fail to perceive that the Moon had the principal
share in the work, however unable he might be to comprehend the theory.
Besides which, the theory, however obvious to us (at least in its main
outlines), was not by any means so intelligible to the men of Galileo’s
age. They might just guess that the Sun exercised some attractive
influence over the Earth, and the Earth again over the Moon, but they
did not know that the Moon attracted the Earth exactly in the same way,
though with far inferior potency, owing to her much smaller mass; and
consequently they were not aware of the Moon’s power to raise the great
tidal wave in the ocean, to which are due the remarkable phenomena so
familiar to the inhabitants of the English coasts.

Galileo would have been wise if he had not touched on a point which
he neither understood in theory, nor had properly acquainted himself
with by practical observation. Good causes are often damaged by bad
arguments, and such was the case on this occasion.[12] There was,
however, something ingenious in his argument. If you take a basin of
water, and move it along quite smoothly and evenly, no great commotion
in the water takes place; but suppose some stoppage or jerk to occur,
the result will be, as we know, very different. Now the Earth has two
motions, one round its axis in twenty-four hours, and the other round
the Sun in one year; every point, then, on the Earth’s surface moves
through space more rapidly while on that side of the globe which is
turned away from the Sun, than on that side which by the diurnal
revolution is turned round in the contrary direction. Here, then, with
the sea lying in its vast basin, and revolving with other things on the
surface of the Earth from west to east every day, and thus accelerated
in its motion through space during twelve hours and retarded during
the other twelve hours, you have on a large scale the same result
that a basin, half full of water, held in your hands and checked by
some retarding obstacle, gives you on a very small and minute scale.
Strange indeed it is that a man who was acquainted with the laws of
motion sufficiently to know that anything thrown or dropped in a
vessel or a vehicle, partook of the motion of the latter and followed
its course (so long as it remained within the vehicle) just as if the
whole were at rest--that he should have failed to perceive that the
ocean, lying in its bed in that mighty vehicle the Earth, would be
carried round in the daily rotation with an uniform velocity, unless
interfered with by the attraction of other bodies. Simplicio, who for
once is right, puts the difficulty, that if the sea behaved in the
way supposed, the air would do so in the same way: the reply to which
is that the air being thin and light is less adherent to the Earth
than the water which is heavier, and does not accommodate itself to
the Earth’s movements as water does; further, that where the air is
not hemmed in, as it were, by mountains and other inequalities on the
Earth’s surface, it really is partially left behind by the diurnal
rotation, and in the neighbourhood of the tropics, where the effect is
chiefly felt, a constant wind blows accordingly from east to west. Our
philosopher had evidently heard of the trade winds, though he had not
acquired an accurate knowledge of their course or of their origin. It
is undoubtedly true that they do help strongly to prove the revolution
of the Earth, because they arise from cold currents of air flowing in
from the north and from the south respectively towards the tropics,
to supply the place of the atmosphere rarefied by the sun’s heat, and
consequently ascending, as is the case in those regions. Then these
cold currents, coming from latitudes where there is a less velocity of
rotation, tend to preserve that velocity and lag behind the Earth as
it revolves, so that they have the effect of north-easterly winds in
the northern hemisphere, and south-easterly in the southern hemisphere.
Galileo’s imperfect information prevented him from using this important
argument.

However, to return to the tides. He had to account for other phenomena,
besides the daily rise and fall, namely, for the much greater rise and
fall which take place soon after new and full moon, and which are known
as the spring-tides. Unable to deny that these were in some way due
to lunar influence, he took refuge in the supposition that the Moon,
when at the full, retarded the motion of the Earth in its orbit, since
as the two travel together round the Sun at those particular times,
they form, as it were, a lengthened pendulum, longer than at other
times by the semi-diameter of the lunar orbit; and therefore (like any
other pendulum) must vibrate more slowly. I should say that he does
not appear to have been aware of the existence of _two_ spring-tides
in each lunation, and therefore only tries to account for one; and it
is obvious that this method of explaining them is not only utterly
inadequate, but even absurd. The Moon truly enough exercises a certain
disturbing influence on the orbital motion of the Earth, but that has
nothing to do with the spring-tides.

There remained the necessity of accounting for the annual, or, more
properly, semi-annual increase of the ebb and flow of the sea. Galileo
suggests that this arises from the angle made by the plane of the
equator with the ecliptic at the equinoxes, owing to which there would
not be the same counteraction exercised by the Earth’s motion in its
orbit on the waters of the ocean at those periods as there would at
the solstices. But it seems that this would rather tend to diminish
the tides than to increase them, as, indeed, would be the case as
regards the last-mentioned explanation with respect to the ordinary
spring-tides. What really does happen at the equinoxes is, that the Sun
and the full or new Moon being at those times vertical to the equator
(or nearly so), they have a greater attractive force than at other
spring-tides over the vast expanse of the ocean, and the tides are
consequently greater. There is also another increase which sometimes
occurs when the Moon happens to be at its least distance from the
Earth at the time of spring-tides, but that was unknown to Galileo.
He touches, however, and very properly so, on the great modifications
in the tides caused by various gulfs, by the forms of the great
continents, and the shapes of different seas--modifications, in fact,
which are well known to be almost innumerable, and have been learnt
only by careful observation and experience.

One of the worst features of this Dialogue is the contempt which the
author shows for those opinions on the subject which differ from his
own; and it is difficult to suppress a feeling of disgust when he
alludes in this way to Kepler, who had partly guessed the true cause of
the tides, and of whom he otherwise speaks in terms of respect.[13]

If a man of science, when he wishes to publish to the world a discovery
or a hypothesis, adopts the form of a dialogue as a method of stating
his case, he ought in all reason to do full justice to the antagonistic
side, and state his opponent’s case as well as his own. I fear that
Galileo failed to do this, not only in this particular dialogue, but
also to some extent in those of the three preceding days. Simplicio,
as I said above, is not a fool, but as a personage in a scientific
argument he is lamentably deficient.

Simplicio at the end of the Dialogue urges that God could, in His
infinite power, cause the tides by some other means than those
suggested by Salviati, to which true and pious (though, perhaps, rather
irrelevant) argument the latter respectfully and devoutly assents.

The concluding sentences are said, as I have remarked elsewhere, to
have been recast or retouched by Father Riccardi.

It is worth noticing that there is a passage in the fourth day’s
dialogue, in which the author alludes to the fact of the Sun being
apparently longer by about nine days in passing along the ecliptic from
the spring to the autumn equinox, than in passing from the autumnal to
the vernal; that is to say, of the northern hemisphere having so much
longer summer than winter, and he treats it as one of the recondite
problems of astronomy not as yet understood. This is an additional
proof that for some reason or another he had not made himself
acquainted with Kepler’s researches; for as soon as it became known
that the planets move, not in circles, but in ellipses, with the Sun
in one of the foci, it was obvious that there would be in every case
(though in some more than others) this inequality to which allusion has
been made, and the Earth, if a planet, would be subject to the same
rule as the rest.

Such, then, is a somewhat imperfect _précis_ of this famous work of
Galileo, which owes its importance to the historical circumstances
connected with its publication quite as much, to say the least of it,
as to its own intrinsic merit.




CHAPTER IV.


Resuming the history of events, we find that early in the year 1632 the
printing of the Dialogue was completed. The author caused some copies
to be bound and gilt and sent to Rome. It was not easy to pass them,
on account of the quarantine; yet some amongst them found their way,
and great was the sensation caused in the ecclesiastical world by their
appearance.

There were a few admirers of Galileo who approved warmly; but there
was the School of Aristotle, as in these enlightened days there is the
School of Darwin,[14] and they could not bear that anything should
be published reflecting on the scientific infallibility of their
great philosopher. Thus we find that Father Scheiner, writing to
Gassendi, observed that Galileo had written his work “contra communem
Peripateticorum Scholam.”

The agitation against the book was successful, and a report arose
forthwith that it would be condemned. The report was no mere _canard_,
as the subsequent proceedings soon showed. In the month of August
of this same year the Master of the Sacred Palace gave orders to the
printer at Florence to suspend the distribution of the copies, and
he also sent for those which had been brought to Rome. Nor was this
all. In the following month the Pope ordered that a letter should be
written to the Inquisitor of Florence, enjoining him to direct Galileo
to present himself in Rome in the month of October, in order to explain
his conduct.

The book had already been examined by special Commission--a step taken
with the view of pleasing the Grand Duke of Tuscany, so as to avoid
bringing the affair before the Inquisition.

The Pope, from whatever cause, was much displeased. This appeared in
a conversation with Niccolini, the Tuscan Ambassador, in which His
Holiness said that Galileo had entered on ground which he ought not
to have touched, and that both Ciampoli and the Master of the Sacred
Palace had been deceived. Still it seemed that, so far, there was no
intention to do more than censure the book and demand a retractation.

The special Commission, of which mention has just been made, after a
month’s interval, reported that Galileo had been disobedient to orders
in the following respects: Affirming as an absolute truth the movement
of the Earth instead of stating it as a hypothesis; attributing the
tides to this cause--_i.e._ to the revolution and movement of the
Earth; deceitfully keeping silence as to the order given him in 1616
to abandon the opinion that the Earth revolved, and that the Sun was
the centre of the universe.

Another memorial (drawn up about the same time), after enumerating
the facts of the case, stated eight heads of accusation against the
philosopher:

  1.--Having, without leave, placed at the beginning of his work the
        permission for printing, delivered at Rome.

  2.--Having, in the body of the work, put the true doctrine in the
        mouth of a fool, and having approved it but feebly by the
        argument of another interlocutor.

  3.--Having quitted the region of hypothesis by affirming, in an
        absolute manner, the mobility of the Earth and the stability
        of the Sun, etc.

  4.--Having treated the subject as one that was not already decided,
        and in the attitude of a person waiting for a definition, and
        supposing it to have not been yet promulgated.

  5.--Having despised the authors who were opposed to the
        above-mentioned opinion, though the Church uses them in
        preference to others.

  6.--Having affirmed (untruly) the equality supposed to exist, for
        understanding geometrical matters, between the divine and
        human intellect.

  7.--Having stated, as a truth, that the partisans of Ptolemy ought
        to range themselves with those of Copernicus, and denied the
        converse.

  8.--Having wrongly attributed the tides to the stability of the Sun
        and mobility of the Earth, which things do not exist.

It must be observed that all this was merely of the nature of an
accusation, and was in no way an ecclesiastical decision.

It appears, too, that some apprehensions were entertained in Rome that
false philosophical and theological doctrines might be drawn out of the
opinion put forth by Galileo. No. 6 of the above-mentioned accusations
points in that direction.

At any rate, no time was lost in summoning the philosopher to Rome,
there to answer for his offences. A message to that effect was
communicated to him by the Inquisitor at Florence, on the 1st October.
Upon this, Galileo, anxious to gain time, and to excuse himself
from going to Rome, if it were possible to do so, wrote to Cardinal
Barberini, and sought the powerful advocacy of the Grand Duke of
Tuscany; he urged his infirm health, and advanced age, nearly seventy
years, as grounds for consideration. It was intimated to him, however,
that although some little time would be allowed him on the ground of
health, yet to Rome he must come; and a threat was added, through the
Inquisitor at Florence, of bringing him fettered as a prisoner if it
turned out that his health was not really such as he represented it to
be. So at last he yielded, and started for Rome on the 20th January,
1633, and, travelling very slowly, arrived on the 13th February, when
the Tuscan Ambassador, Niccolini, who had sent his litter for him,
received him at his Palace. This, with all the freedom it implied, was
indeed an unusual indulgence to persons situated as he was. After a
short time, during which no official steps were taken, he was conveyed
to the office of the Inquisition, and lodged there, but well and
commodiously, by the Pope’s order.

On the 12th April he appeared for the first time before the Court;
he admitted the authorship of the Dialogue; he admitted, too, that
the decree of the Index had been notified to him; but stated that
Cardinal Bellarmine had informed him that it was allowable to hold the
Copernican doctrine as a hypothesis. He maintained further that he
had not contravened the order given him, that he should not defend or
support this doctrine; and he declared that he did not remember having
been forbidden in any way to teach it.

It would seem that this latter prohibition was meant to include
teaching by implication, such as one may do through the medium of an
interlocutor in a dialogue.

It is startling that Galileo should have said among other things on
this occasion, that he had not embraced or defended in his book the
opinion that the Earth is in motion and the Sun stationary; but, on the
contrary, had shown that the reasons produced by Copernicus were feeble
and inconclusive.

After this examination he was well lodged, though treated as a
prisoner, being placed in the apartments of the “Fiscal of the
Holy Office,” instead of in the ordinary chambers appropriated to
accused persons; moreover, he had leave to walk in the garden, and
was attended by his own servant. He said himself, in a letter to his
friend Bocchineri, that his health was good, and that he had every
attention shown to him by the Tuscan Ambassador and Ambassadress. It
is well to note these things, because they dispose of the popular
accusations of cruelty which have been made by ignorant or malicious
controversialists, although the antagonists with whom I am dealing are
too well informed to resort to them.

A slight indisposition from which our philosopher suffered about this
time, illustrated still further the desire which existed to treat
him with _personal_ kindness; the Commissary and the Fiscal charged
with the process, both visited him and spoke encouragingly to him. As
soon as he had recovered he requested to have a further hearing. This
took place on the 30th April; but meanwhile, three theologians, who
had been consulted, Augustin Orezzi, Melchior Inchofer, and Zacharias
Pasqualigo, had each separately presented a memorial to the effect
that Galileo had taught in his book the motion of the Earth and the
immobility of the Sun. At the hearing on the 30th April, being asked
to say whatever occurred to him, he stated that he had read his
Dialogue again--not having seen it for three years previously--in
order to ascertain if there was anything--“se contro alla mia
purissima intenzione, per mia inavertenza”--by which he had been at all
disobedient to the order imposed on him in 1616; and he had found there
were some arguments, notably about the solar spots and the tides, which
he had put too forcibly, and which he thought could be refuted. As
regards the latter of these two points we may, I think, cordially agree
with him in his retractation: but it had been a favourite argument with
him. He also stated on this occasion--not having, I fear, the courage
of his convictions--that he had not held as true the condemned opinion
as to the Earth’s motion, and was ready to write something fresh in
order to refute it, if the time to do so were allowed him.

On this same day (30th April) the Commissary-General of the
Inquisition, with the Pope’s sanction, allowed Galileo to be
imprisoned, under certain conditions, at the Palace of the Tuscan
Ambassador, this favour being conceded on account of his age and health.

He was again called before the Court on the 10th May, and he then
presented a written statement, to which was appended the original of
Cardinal Bellarmine’s injunction, laid on him in 1616. It contained
certain prohibitions, but not the word “teach.”

He pleaded also that he had done his best to avoid all fault in his
book, which he had himself submitted to the Grand Inquisitor. Now
follows what seems like more severe treatment, whether because he had
not impressed his judges with a belief in his candour and sincerity,
or from other reasons. However, the Pope, on the 16th June, gave orders
that he should be questioned as to his _intention_; then, after he
had been _threatened_ with torture (apparently without any view of
putting the threat into execution), and made to pronounce an abjuration
full and entire, that he should be condemned to prison according to
the discretion of the Inquisition; also that his treatise should be
prohibited, and himself forbidden to treat, either by word or writing,
on the subject of the Sun and the Earth.

Yet, with all this, the Pope, two days afterwards, said to Niccolini,
the Tuscan Ambassador, that it was impossible not to prohibit this
opinion (Copernicanism) as it was contrary to the Holy Scriptures,
and that Galileo must remain a prisoner for some time for having
contravened the orders given him in 1616, but that he (the Pope) would
see if the condemnation could be mitigated.

It appears that he was thinking of sentencing him to a temporary
seclusion in the Monastery of Santa Croce, at Florence.

When, in pursuance of the Pope’s order, Galileo was questioned (21st
June), he was asked how long it was since he had held the opinion
that the Sun, and not the Earth, was the centre of the universe; to
which he replied that long before the decree of 1616 he held that the
two opinions could equally be sustained; but that since the decree,
convinced as he was of the prudence of the superior authorities, all
uncertainty in his mind had ceased, that he had then adopted, and still
held, the opinion of Ptolemy on the mobility of the Sun as true and
indubitable. Certain passages in his book were then put to him as being
irreconcilable with the statements he was making; and yet he maintained
that, though he had stated the case _pro_ and _con_ in his work, he did
not, in his heart, hold the condemned opinion. “Concludo dunque dentro
di me medesimo ne tenere ne haver tenuto dopo la determinazione delli
Superiori la dannata opinione.”

Threatened with torture if he did not tell the truth, he persevered
in his answer as already given; upon which the tribunal, after making
him sign his deposition, dismissed him. On the next day, the 22nd
June, he was taken to Santa Maria Sopra Minerva, and brought before
the Cardinals and Prelates of the Congregation, that he might hear his
sentence and pronounce his abjuration.

The accusation was that he had openly violated the order given him not
to maintain Copernicanism; that he had unfairly extorted permission to
print his book, without showing the prohibition received in 1616; that
he had maintained the condemned opinion, although he alleged that he
had left it undecided and as simply probable--which, however, was still
a grave error, since an opinion declared contrary to Scripture could
not in any way be probable.

His sentence was to the effect that he had rendered himself strongly
suspected of heresy in believing and maintaining a doctrine false and
opposed to Holy Scripture in respect of the motion of the Sun and the
Earth, and in believing that one might maintain and defend any opinion
after it had been declared to be contrary to Holy Scripture. He had,
therefore, incurred the censures in force against those who offend in
such ways; from which, however, he would be absolved provided that,
with a sincere heart and unfeigned faith, he would abjure the said
errors and heresies; but, as a penance and as a warning to others,
he was to undergo certain inflictions. The book was henceforth to be
prohibited, he himself was to be condemned to the ordinary prison of
the Holy Office for a time the Holy Office would itself limit, and he
was to recite the seven Penitential Psalms once a week for three years.
The Holy Office reserved to itself the power to remit or change part
or all of the above-named penances. Galileo abjured, accordingly, as
directed.

The well-known legend that after his abjuration he stamped on the
ground with his foot, saying: “E pur si muove” (And yet it, _i.e._
the Earth, _does_ move), is not found in any contemporary author, and
first appears towards the end of the eighteenth century. It is also
to the last degree improbable; Galileo was in far too great dread of
his judges to provoke them by openly perpetrating such an action; and
if he did it _sotto voce_, who heard it, and who testified to it? The
late Dr. Whewell in his “History of the Inductive Sciences,” suggests
that it was “uttered as a playful epigram in the ear of a Cardinal’s
secretary, with a full knowledge that it would be immediately repeated
to his master.” This writer is eminently fair, though naturally he
writes from a Protestant point of view; but he takes the extraordinary
line of maintaining what I think no one who knows all the facts could
possibly suppose, namely, that the whole thing was a kind of solemn
farce, and that the Inquisitors did not believe Galileo’s abjuration
to be sincere, or even wish it to be so; thus he says: “though we may
acquit the Popes and Cardinals of Galileo’s time of stupidity and
perverseness in rejecting manifest scientific truths, I do not see how
we can acquit them of dissimulation and duplicity.” That is, he thinks
the process was a piece of decorous solemnity, adopted to hoodwink
the ecclesiastical public. I do not think it necessary to discuss so
improbable a theory. And the story of “E pur si muove,” as also that of
bodily torture or any personal cruelty being inflicted on Galileo, may,
I venture to think, be dismissed into the realm of fable.

The Pope, without delay, commuted the sentence of imprisonment to
one of seclusion in the Palace of the Tuscan Ambassador, on the
Monte Pincio, after which Galileo was allowed to retire to Sienna,
to the Palace of the Archbishop of that place, Piccolomini, one of
his warmest friends, from whom he received every possible attention.
Indeed, the Archbishop seems to have gone beyond the limits of
prudence, considering the peculiar circumstances of the case and the
temper of the times, in the enthusiasm of his admiration for the great
astronomer, and to have hinted to various persons that, in his opinion,
he had been unjustly condemned, that he was the greatest man in the
world and would always live in his writings, even those that had been
prohibited; such, at least, was the report that found its way to Rome,
and it caused great prejudice to Galileo. He had received permission to
go to his country house at Arcetri, near Florence, on condition that
he lived there quietly, receiving only the visits of his friends and
relatives, in such a way as not to give umbrage; and the report, to
which allusion has just been made, coupled with the accusation that,
under the encouragement of his host the Archbishop, he had spread
opinions that were not soundly Catholic in the city of Sienna, caused
some additional strictness to be enforced as to the manner of his
seclusion.

Thus he was detained for four years in his villa, and was refused
permission to go to Florence for medical treatment, it being, however,
apparent that the villa was sufficiently near to the city to enable
physicians and surgeons to go _to him_ when required. Later on, in
1638, when his sufferings had increased, and he had become (wholly or
partially) blind, permission was given him to reside in Florence, on
condition that he should not speak to his visitors on the subject
of the movement of the Earth. Of this concession he availed himself,
and lived for his few remaining years in Florence, occupying himself
with scientific pursuits. In this same year he published at Leyden a
work entitled, “Dialoghi delle Nuove Scienze”; this, in fact, was his
last work of importance, and he died on the 8th January, 1642, in his
seventy-eighth year.

It is not easy to form an accurate estimate of the character of
Galileo, so far, at least, as affected by the proceedings just related.
By some he has been called a “Martyr of Science”; but a martyr, unless
the word be used in a loose and inaccurate sense, ought, above all
things, to have the courage of his convictions, and as we have seen,
that was hardly the case with Galileo. I will here again quote Dr.
Whewell’s work on the “History of the Inductive Sciences,” and this
time in agreement with his words: “I do not see with what propriety
Galileo can be looked upon as a martyr of science. Undoubtedly he
was very desirous of promoting what he conceived to be the cause of
philosophical truth; but it would seem that, while he was restless
and eager in urging his opinions, he was always ready to make such
submissions as the spiritual tribunals required.... But in this case
(_i.e._ the case of his refusing to abjure) he would have been a martyr
to a cause of which the merit was of a mingled character; for his own
special and favourite share in the reasonings by which the Copernican
system was supported, was the argument drawn from the flux and reflux
of the sea, which argument is altogether false.”

Yet though we deny him the credit of having been a hero or a martyr,
we must not be too severe in condemning him. He was old and enfeebled
by bad health; moreover, his friends had advised him to submit fully
and unreservedly to the tribunal of the Inquisition. And to this we
may add the following considerations. There can be little doubt that
he held the Copernican theory as a very probable opinion; how, indeed,
with his knowledge of astronomy, and with his own discoveries before
his eyes, could it be otherwise? But it is very possible that he had no
fixed, absolute conviction on the subject; he was a sincere Catholic,
and had a deep respect for the Pope and for the Church, and, unlike
modern scientific men, he probably allowed some weight to the decisions
of ecclesiastical authorities. Remembering all this, we may well admit
that there is much to palliate his conduct, though not fully to justify
it.

But his want of candour evidently prejudiced his judges against him.
They accepted his reiterated denials of belief, even a qualified
belief, in Copernicanism, but they did not credit them as being
true. I incline to hold that he would have done as well and given
more satisfaction to the tribunal if he had made a straightforward
defence in some such way as this: that he could not help believing
Copernicanism to be a probable hypothesis on purely scientific
grounds, and _more than this_, the then-existing state of astronomical
knowledge would not have justified him in saying: that he left to
the ecclesiastical authorities henceforth the entire question of
reconciling the theory with Holy Scripture, and that he would not in
future teach it even as a hypothesis, or publish any work so teaching
it, without permission. A statement of this nature, coupled with an
apology for any indiscretion connected with the publication of the
Dialogue, might have availed him better than the line he adopted, and
would at least have had the merit of candour.

A few words may here be added on the scientific character of Galileo;
in this respect he was, with the exception of Kepler, the first man of
his age.

He has the credit of being the discoverer of the first law of motion;
but whether he fully realised this all-important law, or whether it
was one of those happy guesses which we sometimes find to have been
made by men who are the precursors of great discoverers, but who do not
perceive the full scope and the ultimate bearing of the truths on which
they have lighted, I need not here discuss. He did, however, state the
law in a Dialogue on mechanics, published in 1638, in these words:

“I imagine a movable body projected in a horizontal plane, all
impediments [to motion] being removed; it is then manifest from what
has been said more fully elsewhere, that its (the body’s) motion will
be uniform and perpetual upon the plane, if the plane be extended to
infinity.”

This of course involves the principle of the first of the three laws
of motion, the Newtonian laws, as they are frequently called, because
the man whose name they bear was the one who used them clearly and
consistently as the basis of a great astronomical theory. The law, as
now usually stated, is fuller and more explicit than that given by
Galileo, and may be enunciated thus: “Every body perseveres in its
state of rest, or of uniform motion in a straight line, unless it is
compelled to change that state by forces impressed on it.”

It is, however, greatly to the scientific credit of Galileo that
before the close of his life he should have emancipated himself from
the erroneous idea that circular motion alone is naturally uniform,
and should have stated in the language just quoted the true mechanical
doctrine, unknown to his predecessors, unknown even to Kepler,
a doctrine which involved nothing less than a revolution in the
conception of the laws of motion. Nor was this his only contribution
to the science of mechanics; he it was who first understood the law
that regulates the velocity of falling bodies; he perceived that they
were acted upon by an uniformly accelerating force, that of terrestrial
gravity, and that the velocity at any given point is proportional to
the time of descent.

The principle of virtual velocities is said by some persons to have
been discovered by Galileo, and it appears that he stated it fully and
clearly; but he can scarcely be said to be the discoverer of it, as
it had been known to others, and had even--at least as exemplified in
the case of the lever--been noticed by Aristotle. There is, however,
no doubt that Galileo was the greatest man of his day in mechanical
knowledge, whether we attribute more or less weight to the light he
threw on particular details.

In astronomy he was necessarily a discoverer, for the all-important
reason that, as already stated, he was the first man that ever used the
telescope for investigating the phenomena of the heavens. He thus saw
what no one previously had seen,[15] the satellites of Jupiter, the
spots on the Sun, and the moon-like phases of the planet Venus, besides
the greatly increased number of stars, so many of which are invisible
to the naked eye.

The first-mentioned of these discoveries, that of the satellites of
Jupiter, seems to have created an immense sensation among the _savants_
of that day. It _suggested_ that the theories of Ptolemy were anything
but complete or correct, and yet it _proved_ nothing, excepting against
those _à priori_ reasoners, who would not believe that a body round
which a moon circulated could itself be in motion; but the phases of
Venus were simply conclusive against the Ptolemaic system, and for
this reason: According to that system Venus was a planet revolving
round the Earth in an orbit outside that of Mercury, but within that
of the Sun. Now the phases of Venus did not correspond with any
supposed period of her revolution round the Earth, as the phases of
the Moon obviously do, nor did any one ever imagine that the Earth
went round Venus. They did, however, correspond with the time of a
probable orbit in which either Venus revolved round the Sun or the Sun
round Venus; and here again this latter alternative was inadmissible.
There remained, therefore, the one only reasonable solution of the
phenomenon, namely, that Venus travelled in an orbit round the Sun.
This was further confirmed when, in December, 1639, our own countryman,
Horrox, at that time a young curate residing in the north of England,
but gifted with a knowledge of astronomy which would have done credit
to a man of double his age and experience, observed a transit of
the planet across the Sun’s disc. This occurred some few years after
Galileo’s condemnation; but it may be remarked that Gassendi had
already, in November, 1631, witnessed a transit of Mercury. Thus it
appeared that these two planets revolved round the Sun, contrary to
what Ptolemy had supposed. And yet this was not conclusive in favour
of Copernicanism, for the theory of Tycho Brahé was precisely to this
effect: that the planets revolved round the Sun, and that the Sun in
his turn circulated round the Earth. This hypothesis was of the nature
of a compromise, and it has been said that Tycho was led to it by his
interpretation of Scripture rather than of Nature; yet he was one of
the best astronomers and best observers of his age, and had Kepler for
one of his pupils. He had a reason, too, for rejecting Copernicanism
which in his time seemed to have considerable weight, namely, the
incredible distances at which the fixed stars must be supposed to be
placed if the theory were true, since no sensible motion could be
detected among them--apparent motion, that is--such as would result
from the annual motion of the Earth if the stars were at any distance
approaching to that of the planets. We know now how futile this
objection is, but in that age there was an idea that Nature could never
allow of such a waste of space as is implied in these vast distances.
If Tycho had lived longer, we may well doubt whether he would have
adhered to his system. Kepler saw its weakness, and was the first to
discover the true nature of the curves which both the Earth and the
planets describe in their respective orbits; and this, although he did
not know the first law of motion. His books, published in 1619 and
1622, stated not only the elliptic form of the orbits, which no one
previously had found out, but also the important law connecting the
distances of the planets with their periods of revolution.

It is necessary to bear in mind how gradually these various items of
knowledge dawned upon the scientific world, and how imperfect was the
state in which the study of astronomy remained until the discovery
of that great law of gravitation, which binds together and regulates
the physical universe. Men of mature years had not then learnt the
lesson now taught to youths at college, that in natural science we must
discard _à priori_ arguments, and trust to the experimental method
for guidance. It has been said contemptuously that the Cardinals who
condemned Galileo and the Copernican system were not only ignorant of
the science of the present day (which was inevitable), but even of that
of their own day. If that means merely that they were deficient in that
far-reaching intelligence which enables some gifted men to foresee the
future effect of recent discoveries and hypotheses scarcely emerged
from a state of embryo, we may readily grant it.

We may allow also that some of the recent discoveries of Galileo, as,
for instance, that of the phases of Venus, were not at first fully
appreciated, nor their bearing on the controversy perfectly understood,
excepting by professed astronomers. It required careful observation to
perceive that this planet’s phases were only to be explained on the
theory of her revolving round the Sun.

On the other hand, if these ecclesiastics were wise enough to see the
futility of Galileo’s argument drawn from the tides, it is certainly
not for us to blame them; the tides have nothing to do with the
questions then at issue.

And it is only fair to remember that supposing Ptolemy completely
overthrown, as in reality he assuredly was, by the observations on
Venus and Mercury, there remained the system of Tycho Brahé, as has
been remarked already, and this system partly met the case of those
phenomena that Ptolemy failed in accounting for; and although we can
easily see now that it was something of the nature of a makeshift, at
that time there was no clear or conclusive evidence against it.

I proceed now to state what appears to have been the ecclesiastical
force of the two condemnations by the Roman tribunals--that of the
Index prohibiting certain books, and that of the Inquisition punishing
Galileo individually, and forcing him to abjure his real or imputed
opinions on the Copernican system of astronomy. I trust I shall not
lose sight of my position as a _lay theologian_ (in the sense I have
defined the term), or trespass upon strictly ecclesiastical preserves;
but I may surely say at once, that it is evident no decision was
pronounced on any matter of faith. The first case, that of the Index in
1616, I have already discussed; and as for the latter one, that of the
Inquisition, it seems hardly credible that any one should maintain that
the sentence of a Roman tribunal on an individual, however eminent,
could constitute an _ex cathedrâ_ decision on a question of faith. Mr.
Roberts, however, seems to maintain something very like this; but he
does so by taking some strong, and perhaps extreme, statements made
by theologians, such as M. Bouix and Dr. Ward, when writing on some
totally different point, and by urging that if these things are true,
then Galileo’s condemnation was tantamount to a definition _de fide_.

I do not feel called upon to answer arguments of this kind. But there
is another which is more relevant, drawn from the Brief addressed by
Pope Pius IX. to the Archbishop of Munich, about twenty-five years
ago, when the congress of philosophers, of whom Dr. Döllinger was the
leading spirit, had been held in that city. In that Brief, the Pope
states that it is requisite for good Christians to subject themselves
in conscience to decisions pertaining to doctrine that are put forth by
the Pontifical Congregations; and also to such heads of doctrine as are
held to be theological truths by the common consent of Catholics, even
when the denial of these does not involve heresy, but deserves some
other censure.

Theologians, I believe, are not agreed as to whether this Brief is
strictly _ex cathedrâ_, and therefore to be treated as infallible. But
let us assume that it is so. Does the expression, “subject themselves
in conscience,” mean necessarily anything more than a respectful
acquiescence, as distinguished from a full interior assent? And,
allowing that it does even mean this latter, it is for _doctrinal_
decisions that such authority is claimed; and what I am maintaining is,
that the decrees in the case of Galileo were purely disciplinary.

I do not of course deny that the line of demarcation between doctrinal
and disciplinary is sometimes hard to define. But surely the putting
of books on the “Index Librorum Prohibitorum,” whatever be the reasons
stated for doing so, is essentially an act of discipline; and so
also is the condemnation of any individual man for having disobeyed
injunctions laid upon him by authority, or for having disregarded the
principles laid down by the same authority for the regulation of its
practical conduct, so long as they were in force, and not repealed by
any subsequent act.

And this leads me to touch upon another argument of Mr. Roberts, who
says, truly enough, that the authority of Rome is greater than that
of individual theologians, and that Rome must know her own mind. And
because the decision of the Inquisition in 1633, condemning Galileo
personally, referred in strong and marked language to the decree of
the Index in 1616, therefore he infers that the latter is thereby
proved to have been, in the judgment of Rome herself, a doctrinal
decision in the strict sense of the words. It is quite true that the
Inquisition said that Galileo had done wrong in treating Copernicanism
as a probable opinion, since by no means could an opinion be probable
that had been declared and defined to be contrary to Holy Scripture;
they also said in allusion to the decree of the Index that the books
treating of the doctrine had been prohibited, and the doctrine--_i.e._
Copernicanism--had been declared false and altogether contrary to
sacred and Divine Scripture. But a stream cannot rise higher than its
source; and the Inquisition itself, having no other powers but those
entrusted to it by the Pope, had no authority to put any more stringent
interpretation on the decree of 1616 than what it already bore. So
far as its actual wording goes, it is palpably a disciplinary decree,
though founded on a doctrinal reason; and when the Inquisition cited
it as if it were more than this, their language must be interpreted in
accordance with the facts of the case; that is, as meaning that for the
_purposes of discipline_, and for all practical intents and purposes,
it had been defined that such a theory as that of Copernicus was
inadmissible, and on the ground that it was contrary to Scripture as
hitherto understood. But a decision of that nature is not irrevocable;
it holds good as long as the ecclesiastical authorities determine it
should do so, and no longer.

Rome must know her own mind, Mr. Roberts says; and she has shown her
own mind, and borne out the construction I am putting on her acts, by
further and subsequent action; for, after suspending the prohibitions
against Copernicanism--or modifying them--in 1757, a distinct
permission was given in 1820 to teach the theory of the Earth’s
movement; and again, in 1822, the permission was repeated in a more
formal manner, and with the express sanction of the Pope, Leo XII.

Now we know that doctrinal decrees, once fully sanctioned and
promulgated by the Holy See, are irreversible; but disciplinary
enactments are changed according to the needs of the time and the
circumstances of the Christian world.[16] If, then, these decrees
against the Copernican theory of astronomy have been practically
repealed by a decision no less formal than that which called them
originally into existence, it is certain that Rome, who knows her own
mind as well after the lapse of two hundred years as after that of
seventeen years, considered them as appertaining to the province of
discipline and not to that of dogma.

Moreover, Pius IX., when addressing the Archbishop of Munich, must
have been well aware of the above-named facts, and when he enunciated
the simple rule that good Catholics ought to submit in conscience to
the doctrinal decrees of the Roman Congregations--indeed, how can any
one imagine the _rule_ to be anything else?--he must in common sense
be understood to be speaking of decrees wholly different in scope and
character from those relating to the case of Galileo and the system of
Copernicus.

It must, nevertheless, be observed that an argument has been adduced by
Mr. Roberts, and repeated even by so eminent a writer as Mr. Mivart,
as if it were something that threw a new and important light on the
subject. It is that Pope Alexander VII., on the 5th March, 1664,
published a Bull--known as the Bull “Speculatores”--approving a new
and authentic edition of the Index of prohibited books, which Index
contained the decree of 1616, and also the monitum of 1620, ordering
certain corrections in the work of Copernicus, so that the theory he
advocated should be stated merely as a hypothesis--in the preamble of
which monitum, however, it is stated that the principles of Copernicus,
relating to the movement of the Earth, were contrary to the true and
Catholic interpretation of Holy Scripture--and contained also an
edict, signed by Bellarmine, prohibiting and condemning Kepler’s work,
“Epitome Astronomiæ Copernicanæ;” an edict of August, 1634, prohibiting
Galileo’s Dialogue; and in fine, a prohibition of all books teaching
the movement of the Earth and the immobility of the Sun.

In the year following this Bull another Index was also published,
in which the following words occur, under the head Libri, as being
forbidden to the faithful: “Libri omnes, et quicumque libelli,
commentarii, compositiones, consulta, epistolæ, glossæ, opuscula,
orationes, responsa, tractatus, tam typis editi, quam manuscripti,
continentes et tractantes infrascriptas materias, seu de infrascriptis
materiis... De mobilitate terræ, et immobilitate Solis.” This, of
course, is very sweeping, as it includes all pamphlets and letters, and
even writings in manuscript, advocating Copernicanism.

Now, in reply to all this, I think I may remark that even lay
theologians know, or ought to know, that Papal Bulls are divided into
two distinct classes--dogmatic and disciplinary. The first, according
to the doctrine of the Catholic Church, are held to be infallible, but
still only as regards the decisions on faith or morals therein laid
down, and not in respect of the reasons alleged; the second stand in
a totally different position, and are not considered, as a general
rule, to be in any way infallible--in fact, they are liable at any
time to be modified or recalled, as in the instance before us has
actually happened. The Bull “Speculatores” is plainly a disciplinary
one. But I may perhaps be allowed to quote one who is professedly a
theologian--the Reverend Jeremiah Murphy, an Irish ecclesiastic of
learning and ability--who, replying to Mr. Mivart in _The Nineteenth
Century_ of May, 1886, explains, at some length, the real nature of
this Bull. He says: “This Bull, so far from being a special approbation
of each decree contained in the Index to which it is prefixed, is not a
special approbation of even one of them.... It is a re-issue, by public
authority, of all these decrees (those of the Index), but it leaves
each decree just as it was.... The Pope, after referring to the origin
of the Index, says that at that time there was no catalogue, issued by
public authority, embracing the prohibited books and condemned authors,
on which account great confusion has arisen. Accordingly, with the
advice of the Cardinals, the Pope, as he states, has decreed to issue
a new Index. This was done in order that people should ‘have a clear
knowledge of all that was done from the beginning in this matter,’ also
to facilitate references for readers and especially for booksellers.
The Pope goes on to say that he ‘confirmed and approved this same
general Index as aforesaid, composed and revised by our order, and
printed at our apostolic press.’”

Mr. Murphy adds: “No new decree is issued, no new obligation imposed,
no change in the character of any of the decrees is made by this
Bull.... No Catholic theologian would for a moment regard this Bull
as equivalent to an approbation, by special mandate, of any decree
contained in the volume to which it is prefixed.... The Bull is a
purely disciplinary act, perfectly valid until it is cancelled by an
authority equal to that which issued it, but it condemns no new error,
and defines no new truth.”

It may no doubt be urged that there have been certain indiscreet
controversialists who have maintained that the Popes had nothing to do
with the condemnation of Galileo or of the Copernican theory--that, in
fact, it was all the work of the Cardinals.

The Bull “Speculatores” is a good _argumentum ad hominem_ addressed to
such persons, but no one who knows the facts of the case can take up
or ought to take up such a position. As a matter of discipline, the
Popes did give their sanction to the condemnation in question. The
Congregations of the Index and of the Inquisition have no authority at
all except so far as the Pope confers it on them; and whether he gives
them the authority beforehand, or confirms their acts by subsequent
approval, the principle is essentially the same. He delegates to them
certain disciplinary powers, but he does not delegate, and has not the
power to delegate, his prerogative of defining dogma, and enforcing its
belief on the whole Catholic world.

I should not have dwelt at so much length on this particular point
had it not been urged, with what I fear I must call much perverted
ingenuity, by Mr. Roberts that the Copernican theory was condemned _ex
cathedrâ_, as if it were a heresy, by the Pope himself; nor, again, is
it willingly that I quote so frequently the same author’s arguments
with a view to their refutation. He has, however, stated the anti-Roman
case with ability, and without descending to vulgar claptrap. If,
then, his arguments are satisfactorily answered, there is no need of
combating other antagonists.

But I do not at all shrink from considering another and most important
question. I have shown clearly and conclusively that the decrees
against Copernicanism were not definitions of faith; but I am bound to
state now what I believe to have been the effect of them in their own
undoubted sphere, that of ecclesiastical discipline. And here there are
two distinct questions to deal with, which are perhaps sometimes mixed
up together, but which ought to be kept separate.

One is this: What should have been the conduct of contemporary
Catholics, supposed to be scientific men, during the period that the
decrees were in force? The other: What opinion ought _we_ now to form
upon the whole transaction, viewing it retrospectively?

To begin with the first of these two. I have little doubt as to what
ought to have been the conduct of such Catholics--viz., implicit
obedience to the disciplinary rules of the Church so long as the
superior authorities thought fit to enforce them. Thus no good Catholic
could have read the forbidden books, whether by Galileo or by any
other author, without obtaining the requisite permission--a permission
which in these days, at any rate, is given with great readiness to
well-educated persons. Still less could a conscientious Catholic
publish a work advocating the Copernican theory as the true one, or
as most probably the true one. What I think he might have done is to
publish a treatise stating any purely astronomical or mathematical
arguments which seemed to favour Copernicanism as a hypothesis, and, at
the same time, professing his entire submission to the ecclesiastical
authorities, and explicitly disclaiming any attempt to meddle with the
interpretation of Scripture. A protest of some such nature as this
was inserted in an edition of the “Principia” which was allowed to be
published by two Fathers of the order of Minims, Le Seur and Jacquier,
in the year 1742, when the decrees were still in force.

But the first step, and that the most fitting and becoming, would have
been to submit privately to the Roman authorities all the scientific
arguments which the Catholic astronomer--supposing such to be the
case--had discovered as throwing fresh light on the question. No one
has a right to infer from the instance of Galileo, whose arguments were
not all of them sound or convincing, that such an astronomer as I have
imagined would have been treated with contempt or neglect, especially
if he made it evident that he was wholly submissive to the decrees of
the Index, or other Roman Congregations.

Some writers, and notably the late Dr. Ward, have maintained that
besides outward submission, a certain “interior assent” was due to the
decision of the Congregation of the Index--such assent, however, being
different in kind from that given to an article of Faith.

I submit, however, that although the fact of a book being placed on the
forbidden list requires from all good Catholics a respectful assent
to the _principle_ that the Church has a right to enact these rules
of discipline, it does not require an interior act of intellectual
approval. It is said that Bellarmine’s great controversial work was for
a short time placed on the Index on account of some unpalatable opinion
expressed in it. Did he think it necessary to make an interior act of
assent to the decree?

It is true that in the case of the works of Copernicus and others,
the grounds for prohibiting them were stated; but I would ask, are we
obliged to assent interiorly to the grounds alleged for such acts?

In saying this, I do not wish to contradict the opinion of those
theologians who hold that the non-scientific Catholics of Galileo’s age
were bound, by what is termed “the piety of Faith,” to give a certain
interior assent to the pronouncements of the Roman Congregations; and
that on the ground that such persons had no better evidence to act
upon. Their assent then would be very much like that given by dutiful
sons, not yet of age, to the opinions of their father; similar in kind
though stronger in degree.

I am of course assuming the contemporary Catholics, whose case I am
considering, to be men of an obedient and dutiful disposition.

I have confined myself so far to the decrees of the Index. The sentence
of the Inquisition on Galileo affected himself alone. It was no doubt
held up as an example _in terrorem_ for the benefit of others; but
strictly and immediately it concerned Galileo alone, and when he died,
it died with him.

I now pass to the all-important question, what ought we to think of the
whole proceeding, with all the light that has been thrown on it by the
two centuries and a half that have since elapsed? Here, then, I have
to steer a middle course between what I hold to be extreme opinions on
opposite sides, each held by men of note, and men whose principles and
character demand that they should be heard with respect. One opinion
is that of the late Dr. Ward, whom I take as a representative man on
his side, though he is not the only writer who has taken the view to
which I allude, and it is to the effect that the Roman Congregations
acted not only fully within their rights, not only within their
legitimate sphere, but that, considering all the circumstances of their
time, they acted wisely and prudently; that the fault was on the side
of Galileo and his followers, and the Cardinals could not have done
otherwise than they did.

The other and opposite opinion has been stated by no Catholic writer
with greater force than by Mr. Mivart; and it amounts, so far as I
understand it, to this: that the Church has no authority to interfere
in matters relating to physical science, and that the issue of the
Galileo case has proved the fallacy of her attempting to do so; that
without entering into the discussion of what ought or what ought
not to have been done in former times, we of the present generation
have evidence sufficient to show us that scientific investigations
should by right be free from the control of ecclesiastical authority.
The distinguished author to whom I allude has somewhat modified his
original statements, and so I am in some danger of misrepresenting
him, but I think the above is a fair epitome of his views on the
subject; and at any rate I feel myself justified in dealing with him
as he appeared in the widely circulated periodical in which he first
enunciated his opinions, excepting so far as he may have explicitly
retracted what he then said (which I do not believe to be the fact).

I regret that it is my lot to differ from both these able writers. As
against Mr. Mivart, I venture to maintain that the Church has a full
right to control the study of physical science; as against the late
Dr. Ward, that we are not called upon to defend the action of the
Congregation of the Index or of the Inquisition in this particular
instance.

I take Mr. Mivart first, and I may be permitted to say that had it not
been for his somewhat aggressive article, I should not have ventured
to publish my own views on the subject. I call it aggressive because,
though the writer would doubtless disclaim such intention, it seemed
as though he were determined, so to speak, to drive the ecclesiastical
authorities into a corner, and leave them no honourable mode of exit;
letting his readers infer that, because certain untenable decisions
were once promulgated, it results that no further respect need now be
paid to the same authorities when touching on similar questions. Now,
it need scarcely be pointed out that no one would presume to treat
the decision of secular courts--assuredly fallible as they are--in so
contemptuous a way; and if any one practically did so, the executive of
the country where it occurred, unless it had fallen into a condition of
hopeless impotence, would speedily vindicate the rights of the courts
so impugned. But if it should be urged that the two cases are not
parallel, I prefer to confine my argument to ecclesiastical tribunals
only. I maintain, then, that--always assuming the truth of the Catholic
standpoint, which, with Mr. Mivart, I am justified in doing--the Church
has an obvious right to interfere with and to regulate the study of
physical science and the promulgation of scientific theories. It would
be more consistent and more intelligible to deny the right of the
Church to proscribe any theories whatever, or to forbid the reading of
any books, however profane, than to admit it in all other matters, but
deny it in the one case of physical science.

I yield to no one in feeling a deep interest in science generally,
and especially astronomy, the Queen of Sciences, as it is sometimes
called; many sciences, and astronomy in particular, well deserve to
be studied for their own sake, and for the intellectual profit and
pleasure they convey to the mind, putting aside all questions of
practical utility. And yet if we are to measure all the advantages
derivable from the study of natural science against the mighty and
momentous issues which Religion brings before us, it seems to me that
in so doing we are measuring some finite quantity with that which
transcends all our powers of comparison because it is not only vast but
simply _infinite_. If you do not believe Religion, or at least revealed
Religion, to be true, then I understand your worshipping science, or
like the Positivists worshipping Humanity, or any idol you choose to
constitute; but I do not understand a Christian’s doing so, that is,
a Christian in the strict and legitimate sense of the word. Pursue
science by all means, as you pursue literature, art, or any other
innocent human study, but do not make it such an idol as to obscure
your perception of spiritual truths.

And to take the Copernican theory in particular: profoundly interesting
as it is, let us ask ourselves not merely whether it is so important
as to require that all religious considerations should give way before
it, but whether the knowledge of its truth, which we now possess, adds
very materially to the sum total of human happiness. Let us then, for a
moment, think how many men among the millions that people this Earth,
or if we please to limit our inquiry, how many among the civilised
nations of the Earth understand anything whatever about the motions
of the heavenly bodies. No doubt, in England, and probably many other
countries, the elementary books that are taught to children state in a
rough general way that the Earth, like other planets, goes round the
Sun in the space of one year, and revolves on its axis in twenty-four
hours. So far, so good. Suppose you asked those, who as children have
learned these facts, a few ordinary questions in astronomy--I do not
mean things relating to celestial distances, or anything that can
be learnt by heart, but questions requiring thought--how many would
be able to answer you? How many, for example, could explain such a
familiar phenomenon as the harvest moon?--though that has nothing to
do with the Copernican theory. How many could explain the precession of
the equinoxes? Suppose yourself in a room full of educated persons, but
not specially instructed in science, how many could state correctly the
first law of motion?[17]

It is unnecessary to multiply instances; astronomy is obviously
a science adapted not to the multitude of mankind, but to the
comparatively few, who reflect and think. If, then, some check were
given in the seventeenth century, by the action of the ecclesiastical
authorities in Rome, to the progress of physical astronomy, we must
surely allow that the injury to human welfare and human happiness was
so small that we need not dwell upon it.

Mr. Mivart tells us that Descartes was deterred for some time from
publishing his work. Now Descartes, as a pure mathematician, stands in
the highest rank. The method which he invented of applying algebraical
analysis to geometry has facilitated calculation to an extent
impossible to over-estimate; notwithstanding the discovery and adoption
of other and rival methods, that of Descartes still holds its own, and
will probably do so as long as the science of mathematics is cultivated.

But as an astronomer, Descartes can be allowed no such pre-eminence;
his work on Vortices was actually a retrograde step, and in France
it even hindered for a considerable time the reception of the true
doctrine of universal gravitation. So that we may well say if Descartes
had never published his book at all, physical astronomy would have been
the gainer rather than the loser.

Mr. Mivart writes as if he were under some apprehension that the Church
would interfere with his favourite study of biology. I believe his
fears are unfounded. The Roman ecclesiastical authorities are doubtless
conscious of the fact that there is a great moral chasm between the
Europe of the seventeenth century and the Europe of this day. The means
that were adapted for contending against error, real or supposed, two
hundred and fifty years ago, are inapplicable in the present age.
Experience has shown that false scientific theories are pretty sure
to be demolished, time enough being allowed, either by the internal
dissensions of their own supporters, or by the sharp criticism of the
supporters of some antagonistic theory; or, perhaps, the triumphant
progress of new discoveries. Works of a particularly offensive or
irreligious character may from time to time be put on the Index of
prohibited books; but the Church will probably leave purely scientific
hypotheses of all kinds to find their own level, and to stand or fall,
as the case may be.

There remains one objection, brought forward by Mr. Roberts, which I
may notice. It is one of the condemned propositions recited in the
well-known “Syllabus,” that the decrees of the Apostolic See and the
Roman Congregations hinder the free progress of science. But can any
one honestly say that they do? It is one thing to admit that the Church
may for certain reasons put an occasional and temporary check on the
study of some particular science; another, to accuse her of generally
and systematically hindering the progress of knowledge; for be it
observed that the Latin word, _scientia_, from which the above is
translated, does not merely mean physical science.

The Catholic Church has put strong restrictions on the use of
vernacular translations of Holy Scripture--restrictions which, though
greatly modified in practice, are not yet abolished--but a proposition
stating broadly that the Church was opposed to the study of Scripture
would be condemned, and very justly so.

I now come to deal with the other extreme opinion, if I may venture so
to call it--that maintained by the late Dr. Ward, and others--to the
effect that not only has the Church a right to condemn this or that
scientific theory, but that the exercise of such right, as practically
exemplified in the prohibition of certain Copernican works, and in
the condemnation of Galileo, was sound and prudent, and what might
reasonably have been expected. I am not sure whether Dr. Ward goes
quite so far as regards the condemnation of Galileo by the Inquisition;
but he does so in respect of the previous decree of 1616. His ground is
that at that period the Copernican doctrine was, even scientifically
speaking, improbable; while it gave a shock to those who venerated the
traditional interpretation of Holy Scripture. Few men have a greater
respect than myself for the memory of the able writer whose views I
am about to criticise; but physical science was not his strong point.
His knowledge of metaphysical philosophy was great; so, too, was his
knowledge of dogmatic theology; but he does not appear to have been
well versed in natural science, and with that modesty which is a
characteristic of sound and solid learning, he was careful never to
pretend acquaintance with any particular branch of knowledge, unless he
really possessed it.

He was at times even scrupulous in expressing his acknowledgments
for the assistance he had received from others in matters outside
the limits of his own studies; as also in admitting an error if he
felt really guilty of one; showing therein a candour and honesty of
purpose that we do not always meet with. So much I say in tribute to
an honoured memory. I now proceed to state why I cannot follow his
views. It is surely paradoxical, to say the least of it, to maintain
that an opinion is theologically false but scientifically true; or
to state the case more accurately, to maintain that it was right to
condemn as contrary to Scripture what has since turned out to be
true--assuming, of course, this latter to be the fact, which Dr. Ward
fully admitted. It may doubtless be pleaded in mitigation that the
Cardinals only meant that the opinion was contrary to the _traditional_
interpretation of Scripture, and that it was just conceivable that the
method of interpretation would have to be revised hereafter; and we
have seen that Bellarmine’s letter to Foscarini points decidedly in
that direction. Nevertheless, the decree on the face of it appears to
imply more than this, and when coupled with the subsequent condemnation
of Galileo, and strengthened by the repeated prohibition, even in more
stringent terms, of all works favouring the Copernican theory, it
obviously dealt as heavy a blow at the doctrine of the Earth’s diurnal
and annual movement, as could well have been done, short of a dogmatic
decision. It may be quite true that if Galileo had been more prudent
and judicious, much of this would have been averted, and possibly
the decree of 1616 might have been modified or suspended a century
earlier than it actually was so. But without discussing imaginary
possibilities, we take the facts as they stand.

Now to give one or two specimens of Dr. Ward’s mode of writing on
this subject. He says (after stating correctly the Catholic principle
that books theologically unsound should be kept from persons who
are not specially qualified to read them without injury): “In
Galileo’s time all books which advocated the truth of Copernicanism
were theologically unsound. And a most important service was done
by preserving the Catholic flock free from the plague; free from a
most false, proud, irreverent, and dangerous principle of Scriptural
interpretation.”--_Dublin Review_, October, 1865.

I have already said that Galileo would have been wiser if he had
entirely left alone the question of the interpretation of Scripture;
but it must always be remembered that it was not he but his opponents
who commenced the discussion on that particular head. They were weak in
the astronomical argument; and they tried to damage their opponent by
attacking him on Scriptural grounds. It is difficult to understand what
Dr. Ward means by the forcible language I have just quoted, nor how a
principle of Scriptural interpretation, adopted at the present day by
every one, could have been in Galileo’s time false, proud, irreverent,
and dangerous.[18] Dr. Ward grounds his argument, however, on an idea
that he had, to the effect that the Copernican system in Galileo’s day
was “scientifically unlikely:” this, however, is just the reverse of
the truth. It was _unproved_; and, as I have repeatedly said, it is not
even now proved to absolute demonstration.

It is also true that certain most powerful arguments for it were not
then available, as I shall hereafter have occasion to show at more
length; but it was not scientifically unlikely. Galileo had indirectly
damaged the cause by using a certain erroneous argument in its favour;
but then his discoveries had simply pulverised the great rival system
of Ptolemy, and no astronomer, who knew what he was about, could do
otherwise than choose between Copernicus and Tycho Brahé, each of these
being of course somewhat modified in detail. Now the theory of Tycho
Brahé was a new one, still newer than that of Copernicus, and had all
the appearance of a temporary makeshift; it was not probable that it
would receive much approbation in the long run, as in fact it never
did. Probability (I mean, of course, in a purely scientific sense)
pointed strongly to the Copernican theory even in Galileo’s time; and
after Kepler’s celebrated laws had been published, far more strongly
still than before. Of course, as Dr. Ward points out, there _may_
be other reasons of so cogent a nature as to outweigh _scientific_
probability; but that is not now the question: he denies even the
existence of this latter at the period we are treating of; and on this
point he was evidently misinformed.

It is said that the Cardinals of the Index or Inquisition consulted
some astronomers before formulating their decrees, and this is likely
enough; as there is _odium medicum_ in these days, there was doubtless
_odium astronomicum_ in those days.

And we may easily imagine how the philosophers who believed in the
infallibility of Aristotle looked with horror and perhaps contempt on
the School of Galileo. If people once persuade themselves that physical
science is to be learnt merely from tradition, or from _à priori_
arguments, they will naturally have an antipathy to the discoveries
made by actual observation and experiment. If men such as these were
called in to advise the Cardinals, we may well admit it as a mitigating
circumstance, forbidding us to pass a severe judgment on the conduct
of the ecclesiastical tribunals. It is no part of my contention, and
indeed the very reverse, to lay excessive blame on the Congregations
of the Index and Inquisition; but neither, on the other hand, do I
understand why we should give them our unqualified approval.

I feel that the opinion I have expressed above, and which might
otherwise be considered by some persons as presumptuous towards the
ecclesiastical authorities, receives great confirmation, and at the
same time what is tantamount to an acquittal from all disrespect to
the Church and her authority, by the following extract which I give
from the article entitled, “Dr. Mivart on Faith and Science,” published
in the October number of _The Dublin Review_ (1887), by the Bishop
of Newport and Menevia, the Right Rev. J. C. Hedley. Not only does
the high character of the author, both as a theologian and a man of
scientific knowledge, give a sanction to all that is contained in the
article, but the Review in which it appears, having for its proprietor
another Bishop and an able ecclesiastic for its acting editor, carries
with it a stamp of Catholic authority such as few periodicals possess.
After some other remarks the Bishop of Newport proceeds thus:

    I do not by any means wish to deny that the case of Galileo has
    had an important effect on the action of Church authorities.
    It seems quite clear that it has made them more cautious
    in pronouncing on the interpretation of Scripture when the
    sacred text speaks of natural phenomena. The reason of this
    is not so much the fact that science has proved authority
    wrong in one case, as because that case, taking it with all
    its circumstances, was one the like of which can never happen
    again. The Galilean controversy marked the close of a period
    and the opening of a new one. The heliocentric view was the
    first step in modern scientific expression. Before the days
    of Galileo men spoke of what they saw with the naked eye, and
    on the surface of things; thenceforth they were to use the
    telescope and the microscope; they investigated the bowels
    of the earth and the distances of the heavens. It was a
    far-reaching and most pregnant generalisation when men first
    took in the idea that the arrangements which their books had
    hitherto called by the expression “nature” were merely a very
    few of the most obvious aspects of a vast organisation, which
    could be, and which must be, searched into by observation. At
    once a multitude of familiar phrases lost their meaning, and
    many accepted truths had to be dethroned.

    And the effect of the discussion in the days of Galileo was not
    only to make men revise their formularies about the earth’s
    motion, but to impress them most forcibly with the possibility
    that such a process might have to be gone through about a very
    large number of other things. The prevailing views were held
    by the Church authorities as by every one else. They were not
    really a part of the Divine revelation. Some people thought
    they were, and (we may admit it was a misfortune) the very
    authorities who had to pronounce, used language which was
    to some extent mistaken in the same direction. On the other
    hand, it is clear now that men of mark and standing asserted
    over and over again, that the new theories need not in any
    point contradict Holy Scripture. It was a matter which was not
    clear all at once. It is often not immediately evident that
    novel scientific views do or do not contradict Revelation.
    They have to be made precise, to be qualified, to be analysed,
    and that by fallible men. During the process many Catholics
    will naturally make mistakes, and there is no reason why, now
    and then, Church authority itself should not make a mistake
    in this particular matter. When the requisite reflection has
    had time to be made, then it is seen, as it was in the case
    of the views under discussion, that what was held by Catholic
    persons was something quite apart from Catholic faith. And we
    have no objection to admit that reflection was quickened, and
    caution was deepened by the case of Galileo. In this sense,
    and not in any other, that case may be called “emancipatory.”
    If the Church authorities ever feel themselves called upon to
    pronounce on the dates or the authorship of the Hexateuch, or
    on the formation of Adam’s body, they will proceed--we may say
    it without suspicion of undutifulness--with more enlightened
    minds than the Congregations which condemned Galileo.

    The teaching Church is composed of fallible men, who must
    sometimes, in certain departments, make mistakes, and who
    must learn by experience as other men learn. The part of a
    dutiful Catholic is to lessen the effect of mistaken decisions
    by prudent silence or respectful remonstrance in the proper
    quarter, and not to make scandal worse by inept generalisations
    and unnecessary bitterness.

Further on, the Bishop says:

    I do not decline to face the difficulty of Galileo’s compulsory
    retractation. It seems to me that either Galileo had
    sufficiently strong reasons to prevent his mind from making
    the retractation or not. I think it possible he had not. It
    does not seem that he had anything like evidence that the earth
    moved. If he had not, there was no reason why he should not
    assent to a strong expression of authority, that authority
    being one to which he owed filial obedience.... Still, if
    Galileo had present to his mind strong proof of the correctness
    of his own teachings, I do not hesitate to say that he was
    wrong, and, indeed, committed sin, in making the retractation
    demanded.

On the purely astronomical question whether Galileo had evidence that
the Earth moved, I presume that the Bishop means _conclusive_ evidence;
for evidence of some kind he surely had; not conclusive, it is true,
but good as far as it went. Long before Galileo was tried by the
tribunal of the Inquisition, his contemporary, Kepler, had published
those important astronomical laws which still bear his name, and which
tended powerfully to corroborate the theory of the Earth’s motion.
Apart, however, from this, as I have already intimated, I think there
was good ground for the opinion in question.

This, however, is to some extent a digression. I have quoted the Bishop
principally in order to strengthen, by his high authority, the line
of argument I have ventured to pursue, which, in effect, is this:
that the principle on which the Roman Congregations acted in Galileo’s
case was sound, but the application of it in the particular instance
mistaken and injudicious.

I may also be permitted to cite, as confirming my own opinion, the
words of the distinguished writer to whom, in common with all students
of the Galileo case, I am so much indebted, M. Henri de l’Épinois. They
do not, of course, possess the same theological authority as that of
the prelate I have just quoted, but, coming from a learned Catholic
layman, they are well worthy of attention. These are his words:

    Galilée, en établissant les principes de mécanique qui sont ses
    titres de gloire, comme en soutenant la doctrine de Copernic,
    a rencontré pour adversaires déclarés les partisans de la
    philosophie d’Aristote, qui combattaient aussi bien Képler
    à Tubingue, et Descartes en Hollande. Ils appelèrent à leur
    aide des textes de l’Écriture, les opposèrent aux affirmations
    de Galilée. Pour se défendre celui-ci voulut expliquer ces
    textes. Dès lors, il changeait l’interprétation jusque-là
    admise par l’Église et éveillait les justes susceptibilités des
    Catholiques. Avait-il raison? Avait-il tort? Il avait tort dans
    plusieurs de ses propositions, et sa conduite manqua souvent
    de prudence; il avait évidemment raison dans sa doctrine
    fondamentale. En fait le tribunal s’est trompé en condamnant
    comme fausse et contraire à l’Écriture une doctrine vraie et
    qui pouvait s’accorder avec les textes sacrés. Il a manqué de
    prudence en se montrant trop circonspect, et a ainsi dépassé le
    but. Il faut toutefois le remarquer. Aujourd’hui il est facile
    de dire: le tribunal a eu tort; mais en 1616, en 1633, la
    plupart des savants, les Universités et les Académies disaient:
    il a raison....

    Tous les témoignages contemporains nous montrent que deux
    pensées, deux opinions, deux influences étaient en présence:
    d’un côté les Aristotéliciens acharnés contre Galilée,
    détestant ses principes, voulant les anéantir; de l’autre les
    papes, les cardinaux, pleins d’estime pour Galilée, mais qui
    voulaient prévenir les fâcheuses conséquences de sa doctrine.

    Selon que l’une ou l’autre de ces influences domina dans les
    conseils, on tint une conduite différente: tantôt sévère et
    rigoureuse, tantôt douce et indulgente. Mais il n’y eut point
    là, comme on le prétend encore, de lutte entre la science et
    le Catholicisme: la question fut débattue entre la science et
    l’Aristotélisme.[19]

It was not till the year 1757 that any authoritative step was taken to
relax the prohibitions imposed by the Index on the works advocating the
Copernican system. This was more than a century after the condemnation
of Galileo, seventy years after the publication of the “Principia,”
and thirty years after the discovery of the aberration of light. Even
Dr. Ward allows that it might have been more prudent to remove the
prohibitions some forty or fifty years sooner than was actually the
case. No one, he observes, supposes the Church to be infallible in
mere matters of _prudence_, and I think that in making this statement,
which, I presume, every theologian would at once endorse, he half
admits the principle for which I contend; for if the Roman authorities
could err in point of prudence in leaving the censure so long in force,
might they not err--I mean, of course, as to the prudent administration
of discipline--in inflicting those censures at all, or at any rate in
applying them so rigorously in practice as was done in the instance of
Galileo?

However, be this as it may, in the year 1757 the relaxation of the
censures took place; in 1820, on the 16th August, a distinct permission
was given for teaching the movement of the Earth; and again on the
17th September, 1822, a re-examination of the whole subject having
taken place, a decree appeared, sanctioned by the Pope, Leo XII.,
in which the Inquisitors General, in conformity with the decrees of
1757 and 1820, declared that the printing and publishing at Rome of
works treating of the movement of the Earth and the immobility of the
Sun, according to the opinion of modern astronomers, was henceforth
permitted. Thus the decree of 1616 was practically abrogated.

Mr. Mivart, among other remarks on the proceedings in Galileo’s case,
says that no amends were ever made by the authorities of the Church
for the injustice done to the philosopher, but he does not state what
kind of amends or what sort of apology he expected. If he means that
no personal reparation was made to Galileo, that is doubtless true;
nor was any sacrifice ever offered to his Manes. Indeed, it must be
allowed that the ecclesiastical authorities hindered the erection,
after his decease, of a monument in his honour. Nor is this a matter
for surprise; it may be taken for granted that the object of those who
desired to erect the monument was to pay an especial tribute of respect
to the deceased astronomer as one who had suffered unjustly; and that
was precisely what the Pope and Cardinals of that age would not for a
moment admit.

No personal amends, then, were made to Galileo in life or in death; but
I think this was not the point to which Mr. Mivart intended to allude.
I believe he had in his mind a different sort of reparation--that,
namely, supposed to be owing to the injured cause of Science. If that
be so, then I can only say that he must have been unaware of the facts
above mentioned, of the proceedings taken in Rome in 1757, in 1820, and
in 1822.

The adjustment of the relations of revealed Religion with physical
Science is often perplexing, owing partly to mistaken zeal in
insisting on particular interpretations of certain passages in Holy
Scripture, and partly to the prevalence, at different times, of
doubtful scientific theories, which flourish for a time, and then fade
away because they fail to stand the test of continued and rigorous
investigation.

Instances of both these will readily occur to the mind, and the
Copernican theory in the seventeenth century will be a prominent one,
as coming under the first of the two heads. But it is not fair, as
I have already argued, to be too severe upon the men who clung with
tenacity to the old traditional interpretation of Scripture. It is,
in fact, only right so to cling until some just reason is shown for
introducing a fresh interpretation. In this case there were some good
reasons, no doubt; but there were also bad reasons alleged, and, as we
have seen, Galileo, with all his great ability and mechanical knowledge
so far beyond his age, could yet damage his cause with unsound
arguments.

Such being the case, amidst the whirlpool of good and bad
arguments--that drawn from the tides being by no means the only one of
the latter class--it is not astonishing that even able and intelligent
men were misled.

The antipathy to adopting a new system of the universe--a system
which demolished many cherished ideas and traditional opinions--was
overwhelmingly strong; the reasons uncertain, or, at least,
inconclusive. The discoveries of Galileo had, no doubt, overthrown the
system of Ptolemy, but they had not established that of Copernicus, so
long as there remained what may be called the tentative theory of Tycho
Brahé, who was one of the greatest observers of his day. Though he
did not unravel the true cause of the motions of the heavenly bodies,
and went, in fact, in a wrong direction, we must never forget the
important services he rendered to science. He was the first to employ
refraction as a correction to the apparent positions of the celestial
bodies; his collection of instruments, on which he had expended the
whole of his private fortune, was the finest that had ever yet been
seen; and, in fact, his observations, utilised by others, had a great
share in leading to the discovery of the real nature of the planetary
movements.[20] Small blame, then, must be meted out to those who held
on for a time to the system excogitated by so enlightened a man. I do
not mean to deny what I have already stated--that the Cardinals who put
on the Index of forbidden books the works of Copernicus and others, and
those who condemned Galileo, were unable, astronomically speaking, to
read the signs of the times. All I am asserting is that there was much,
even from a scientific point of view, to excuse their inability.

They put forward as their main objection that the new theory
contradicted Holy Scripture, and adhered to that rigidly literal
interpretation of it, which has since then been necessarily given up,
and which seems somewhat strange to us, accustomed as we now are to
a far greater latitude of interpretation than they even dreamed of.
We who have learned that the six days of Creation are not to be taken
in their strict sense;[21] who have sound reason for holding that the
Deluge was only universal in the sense of covering that part of the
earth then inhabited by the human race; and who are told by some
people, including learned ecclesiastics, that it was more restricted
in its operation even than this; and who finally hear it said by men
of undoubted orthodoxy that the evolution of man from some lower
animal, so far as his _body_ is concerned and so long as you do not
include his soul and his rational faculties, is consistent with the
Christian faith--we, I say, who are familiar with these non-literal
interpretations of Scripture, find it difficult to comprehend the
standpoint adopted and maintained with such tenacity by the Cardinals
of the seventeenth century.

There were, moreover, other very cogent reasons which, though not put
prominently forward, may well have worked upon their minds; reasons,
indeed, which must strike the really thoughtful man. Let us consider
this one point. In old times, when the Earth was believed to be the
actual centre of the physical universe, it was easy to suppose that
it was the sole abode of life. But if you believe that the Earth, far
from being such a centre, is only one amongst many planets revolving
round the Sun; and, further, that the Sun himself is only one of a
mighty host of stars, some of which may have planets revolving round
them, you naturally ask yourself immediately, are none of these worlds
inhabited except our Earth? Truly Scripture says nothing to contradict
the opinion that there are inhabitants and rational creatures to be
found elsewhere; but, nevertheless, the history of the Creation and
Redemption of the human race reads as if such creatures, intelligent
beings like ourselves, lived upon this Earth, and nowhere besides.

I know not how far thoughts and speculations of this nature passed
through the minds of the ecclesiastics, and other men of religious
feeling, in the age of Galileo. They have since then been sifted more
or less by scientific men, and various opinions have been suggested.
Some went so far as to think it possible that the Sun was inhabited.
So able an astronomer as Arago, to say nothing of others, thought
such might be the fact. No one thinks so now. The tendency of modern
thought, strictly speaking _modern_ (that is, the most recent), is
rather to discredit such imaginations. The various observations made
upon the Sun, including those made by the use of the spectroscope, have
shown that the supposition of his being inhabited is simply incredible.
For other reasons the same result has been reached with regard to
the Moon. Then as to the planets, although there are no such cogent
reasons, we may fairly say that the probability is against any one of
them being at the present moment fitted for the habitation of such a
creature as man. Some persons would make an exception in favour of
Mars, where a recent French observer imagines he has detected signs of
work as if by human hands--a stretch indeed of imagination.

But the planets are probably not all in the same stage of what may be
termed geological history. Some may very possibly be in the same state
in which the Earth was a few millions of years ago, long before it was
fitted for the reception of man on its surface, or, indeed, for that of
any of the higher mammalia. The Earth had had a long history, and had
undergone vast changes, ranging perhaps over many millions of years,
before man appeared on the scene; and the period that has elapsed
since that event, whatever the date of it may be, is simply nothing in
comparison of the ages that had previously rolled by since the first
moment when the darkness gave way, and the light appeared. It is, then,
far from unlikely that our own Earth is the only planet in the solar
system which at the present time is suitable for the habitation of man,
or creatures resembling him.[22]

Passing then from our own system, we come to the myriads of suns, some,
we may well believe, far greater than our Sun, which are spread through
the realms of space.[23] Many of these we may reasonably suppose are
surrounded by planets, and in one or two cases there are special
reasons for thinking that some opaque body intervenes occasionally
between the star and ourselves. But the conditions under which several
of the stars (we know not how many) exist, is very different from that
to which we are accustomed here with our own Sun. There are double
stars which appear to revolve round a common centre of gravity, a
system of two suns. Have each of them, or have both of them in common,
a set of planets moving round them? Who can tell? And where there
are stars with planets accompanying them, does any one know in what
state those planets are? The whole subject, however interesting as a
speculation, is shrouded in impenetrable mystery.

From all this it follows that although there certainly may be rational
and intellectual inhabitants on some or other of these distant worlds,
yet, on the other hand, there _may not_ be. And it is perfectly
possible that our Earth, minute little object as it is, comparatively
speaking, may still be the great and favoured life-house of the
universe, the _moral_, though not _material_, centre. That the Earth
is not the physical centre of the universe we now are well aware; nor
is the Sun the centre; nor, indeed, do we know whether there is any
such centre at all. There is good reason for thinking that the Sun,
with his attendant planets, is in motion in a certain direction in
space; and I may observe that this direction is not in the plane of the
Earth’s orbit, or anything near it; so that though the Earth describes
an elliptical orbit with regard to the Sun, its path in space is some
kind of spiral curve, that is as it would appear to a being poised for
a time in some point of space far away outside our orbit, having the
necessary powers of vision, and having a plane of reference from which
he could take his observations.

What else this gifted being might see--whether he would observe some
great central body round which the whole of the heavenly bodies
revolve, or, as seems more probable, would detect, instead of one,
many centres, each with its own group--all this we do not and cannot
know, and we must be content, at least so long as our life here below
continues, to remain in profound ignorance.

Seeing, then, how wide in extent and how difficult of solution are some
of the speculative problems, originating in the Copernican theory, it
can be no matter of surprise that the ecclesiastics of the seventeenth
century recoiled from it with more than common aversion.




CHAPTER V.


As a sequel to the story of Galileo, I think it may be interesting to
inquire what the evidence, as _we now have it_, proves with regard
to the truth of the Copernican theory, there being two opposite and
contradictory errors on this subject, and these not merely popular
errors, but shared to some extent by educated and otherwise learned
men. But I must, before proceeding, remind my readers that I use the
word _Copernican_ simply to signify the system of modern astronomy,
that in which the Sun is the centre round which the Earth and the other
planets revolve, and not as meaning the precise theory of Copernicus,
which (as I have said) was overthrown by Kepler, when he discovered
that the planetary orbits were not circular but elliptical, the Sun,
moreover, not being strictly in the centre, but in one of the foci of
the orbit.

Now it is a plain fact, which all persons must perceive, that either
the Earth revolves on its axis in twenty-four hours (more accurately
23 hours 56 mins. 5 secs.), or else that the whole of the celestial
bodies are carried round the Earth in that same time. It is also a fact
no less perceptible to _careful_ observers, that either the Sun goes
round the Earth in the course of a year, or else that the Earth goes
round the Sun. The question is how these facts are to be accounted for.

The first of the two errors I have just mentioned is that which
supposes the Copernican theory to have been directly and conclusively
proved. This I imagine to be very common, and to arise from the
elementary books learnt by schoolboys, which state (naturally enough)
the modern theory of astronomy without the reasons that support it.

We need not dwell long on this point. Persons who have got this
erroneous impression misunderstand the nature of the evidence. Some
things in astronomy can be positively proved from observation, as,
for instance, the existence of sun-spots. Many things in mechanics,
chemistry, optics, and other branches of physical study can be
demonstrated by experiment. The motion of the Earth round the Sun
cannot, however, be so treated. It is inferred, and very rightly so,
from the fact that it explains completely and easily all the observed
phenomena, while, on the other hand, there are certain things which, as
_far as our present knowledge goes_, cannot be explained in any other
way; and the same argument applies to the rotation of the Earth on its
axis. But though all this is perfectly clear so far, who can possibly
say that as science progresses some explanation may not be hereafter
found consistent with the antagonistic theory--consistent, let us say,
with the system of Tycho Brahé, or some modification of it? I need
not add that I consider the future discovery of such explanation as so
improbable, that one may practically dismiss the idea, but I should be
sorry to deny it as being conceivably possible.

The other, and opposite, error is that of certain well-meaning but
ill-informed persons, who imagine that the Copernican theory is even
now doubtful and liable to be overthrown--liable, I mean, in a real and
practical sense, and not by distant contingencies, such as those at
which I have just hinted, and which may be considered as shadowy and
intangible. I do not suppose that amongst educated men there are many
such scientific recusants; but at any rate it may be useful to give a
short summary of the evidence on which the Copernican conclusion is
based. In doing this I fear I shall tire the patience of my readers by
partly repeating Galileo’s own arguments, which I have already quoted
in discussing the Dialogue. This cannot easily be avoided, for much
of his reasoning is so sound and so forcible, that after the lapse of
more than two centuries we can add but little to it. On the other hand,
there are grave mistakes that must be shunned; and, moreover, there
have been discoveries made since the day when the Dialogue was written,
of inestimable importance.

The best way of treating the question is to resume the history of
astronomical research from the point where we dropped it; that is, at
the time when Galileo first made known to the world the result of his
observations.

It ought to be clearly understood that from the moment the telescope
was turned on the heavens, the old system of astronomy was doomed, and
nothing could finally have saved it. For a time prejudice and other
more creditable feelings kept it floating on the sea of speculation,
but such a state of things could not last; and the startling
information that men like Galileo, Fabricius, and Scheiner imparted
to the scientific world, could not fail to expel the old theory of
the universe from the minds of men--at least, men of intellectual
capacity--gradually and slowly, but yet most surely.

Now we have seen what the revelations were which the telescope at once
displayed, even in its comparatively rude and imperfect state. There
were the spots on the Sun, the satellites of Jupiter, the phases of
Venus, the greater apparent size of the superior planets (Mars and the
rest) when on the opposite side of the Earth from the Sun, this last
phenomenon being quite inconsistent with the system of Ptolemy.

One consequence of all this was that the less enlightened men of
the old school indulged in a violent antipathy to the new-fangled
instrument, which threatened to overthrow their time-honoured
traditions, and simply refused to believe in the telescope and its
results. Thus the principal professor of philosophy at Padua, when
invited by Galileo to look through his glass at the Moon and the
planets, pertinaciously refused to do so. Simplicio, who, of course,
represents in the Dialogue the prejudices of men of this stamp, admits
(as we have seen) his feelings on this subject, and his suspicions that
the new discoveries were to be attributed to optical errors. He was
willing to be corrected if mistaken, but such had hitherto been his
opinion.

It was not, however, to be expected that men of sound sense would
allow themselves to be misled for any length of time by fallacies such
as these. Continued observations carefully made are sure to correct
mere optical errors, and after a reasonable interval it must have been
evident that the phenomena discerned through the telescope were facts
that had to be dealt with--not phantoms to be ignored.

Thus, when it was found that the planet Venus presented to the eye
phases such as the Moon does, instead of always appearing like a round
body, it became evident that she revolved, not as Ptolemy supposed,
round the Earth, but round the Sun, an inference subsequently confirmed
by the observation of her transits over the Sun’s disc.

This being so, the adherents of Ptolemy had to meet this difficulty:
here was a planet much nearer to the Earth than to the Sun,[24] and
yet revolving round the latter in preference to the former. There was
clearly, then, _some_ attractive force belonging to the Sun (whatever
its nature might be), greater than that of the Earth, which Venus
obeyed; the same was true of Mercury, with the difference that this
planet was much nearer to the Sun. Then as regards the superior
planets, Mars, Jupiter, Saturn, the probability that the Sun was
the great central power that controlled their movements was a very
strong one. There is but little to add on these topics to Galileo’s
own forcible argument in the third day’s dialogue; he is, however,
inaccurate in his figures, and states that Mars appears sixty times as
large when in opposition to the Sun, as at conjunction. More recent
observations have shown that he appears rather more than thirty times
as large when at his nearest point to the Earth, than he does when
near his conjunction with the Sun, and consequently at his farthest
point from the Earth; but this variation is quite sufficient for the
argument, and proves incontestably that if Mars revolves round the
Earth as in any way the centre of his orbit, it must be in an ellipse
of so great eccentricity as no one could reasonably imagine him to
do; indeed, the anti-Copernicans of Galileo’s day knew nothing of the
elliptic motions of the planets; neither, as we have seen, did Galileo
himself.

The same argument, drawn from the apparent size of the planet at
different periods, applies also to Jupiter and Saturn--the other
exterior planets were discovered much later--only not so strikingly as
in the case of Mars. The improbability, if we once admit that all the
planets revolve round the Sun, that the Earth, occupying the position
it does, should be at rest, while the Sun, controlling the motions
of the planets (vast bodies, some of them), circled, nevertheless,
round the Earth; the improbability, I say, of this is so great as to
be almost overwhelming; at any rate, unless the difficulties of the
counter hypothesis were shown to be insurmountable, which, as we know,
is far from being the case. It was of course possible, without going
the lengths of the Paduan professor, and setting oneself against the
telescope altogether, to admit the facts but deny the inferences; to
grant, for instance, that Mars appeared to have a diameter more than
six times as great in one position as in another, and to attribute
it, as I hinted just now, to some extraordinary eccentricity in his
orbit round the Earth; but it is not wise to look through a telescope
with the eyes of the body open and the eyes of the mind closed;
and generally it is but right to be guided by clear and distinct
probabilities when discussing questions of natural philosophy on
scientific grounds--and it is of these alone that I am at the present
moment speaking.

It must be borne in mind distinctly that the discovery of the moon-like
phases of Venus, showing her to revolve round the Sun, was simply
conclusive as against the old system of Ptolemy, which had so long been
the received system of astronomy. The theory of Tycho Brahé, or some
modification of it, was the only one that could henceforth be adopted.
But when you dethrone an ancient theory which has for centuries held
an almost undisputed sway, you have to reconsider your whole position,
and compromises such as that of Tycho are not always adequate to the
emergency.

But these considerations formed only a part of this complicated
controversy. The anti-Copernicans of the seventeenth century would
not even admit the revolution of the Earth on its own axis, and were
consequently forced to hold that the whole of the heavenly bodies were
carried round this our globe in twenty-four hours. In ancient times,
when men knew little or nothing of the sizes and distances of the
Sun, the planets, or the stars, such a belief was quite reasonable
and natural; they thought the stars were set as if they were jewels
in a hollow sphere, which was turned round its poles each day. But
the astronomers of Galileo’s day knew something far more accurate
than this; he himself, as we observed in the Dialogue, greatly
under-estimated the distance and the size of the Sun, and had but a
very imperfect idea of the enormous interval that separates us from the
stars; yet he evidently perceived the improbability of all these vast
and remote bodies revolving with an almost inconceivable velocity round
the Earth every twenty-four hours. And what must be _our_ judgment
on such a subject, seeing that we know the Sun’s mean distance to be
about 92,000,000 miles, more than nineteen times as much as Galileo’s
estimate? And yet some of the planets are farther and much farther
from us than the Sun. Then as regards the stars, α Centauri, the
nearest of them, is calculated to be more than 20,000,000,000,000 miles
distant; but this calculation supposes the truth of the Copernican
theory, and that we may not seem to argue in a circle, we will not use
it, but content ourselves with saying that, from certain reasons about
which there can be no mistake, we are sure that the distance of the
stars is very considerably greater than even the remotest planet in
our own system, which is Neptune. Now, this planet’s distance from the
Sun is computed at 2,775,000,000 miles, and if, indeed, he is carried
daily round the Earth in a circle, it must be with a velocity exceeding
that of light; the stars, therefore, with a velocity far greater still.
Now, nothing with which we are acquainted moves with so great a speed
as light--or, as some men call it, _radiant energy_, meaning thereby
to include heat as well as light in the term--a speed estimated at
186,000 miles in a second of time. Are we then to believe that the
stars are carried in a circle round the Earth every day at a velocity
much exceeding even this? It seems almost enough to ask such a question
without pausing for the answer. The simple rotation of the Earth on its
own axis explains all the phenomena without resorting to such extreme
suppositions as those just mentioned.

It is remarkable that no one of any note--at least, in modern times,
for I am not so sure about the ancients--ever appears to have
suggested the intermediate theory of the Earth revolving on its axis,
and yet remaining stationary as regards any motion of translation.
With our present knowledge of astronomy we could not entertain such
an opinion, though in the early part of the seventeenth century it
might have been considered plausible. Since, however, it has not been
maintained by any noteworthy author, we need not further discuss it.

The reader will bear in mind what has already been said on this
branch of the subject in the second day’s dialogue,[25] and it is not
necessary to repeat it in detail. It may, however, be useful to mention
a few experiments of a later date, which have tended to confirm the
truth of the Earth’s diurnal revolution.

Before the close of the seventeenth century it was observed that a
diminution of gravity occurred at, and near, the equator. This was
proved by the vibration of the pendulum, an experiment associated
chiefly with the name of Richer; and it has, if I mistake not, been
since then carefully tested by spring balances. This phenomenon is
owing partly to the spheroidal figure of the Earth--itself the result
of the rotation on the axis--but principally to the centrifugal
tendency being greater at the equator, from the higher velocity of
rotation.

I have already alluded to the trade winds, and the argument to be drawn
from them, which I think a sound and strong one; but I need not dwell
on it further.

It is, however, well worth remembering that in our own day another
proof has been given, which has been generally allowed to be an
important one. It is the result of an experiment of Foucault, and is
simply this: if a pendulum, with a heavy weight attached to it, be
made to oscillate in a plane due north and south, say in the latitude
of Paris, the pendulum, after a time, and supposing it to continue in
movement long enough for the purpose of observation, will oscillate
in a direction slightly north-east and south-west. Now the pendulum
moves naturally always in the same direction, backwards and forwards,
as originally started, and if the Earth were shaped like a cylinder
no change would be detected; but the spherical form of the Earth, as
it rotates on its axis, here makes the whole difference; the floor
of the room where the pendulum vibrates is carried round the axis of
rotation, as everything else is, but the plane of oscillation remaining
the same--or parallel to the original one--it no longer points north
and south. At the equator this phenomenon would disappear, and in the
southern hemisphere it would be the other way: that is, the pendulum
would vibrate north-west and south-east.

The same thing is exemplified by the small machine called the
gyroscope, where a heavy disc, so adjusted as to revolve freely in any
given direction, independently of the frame in which it is placed, will
continue, when once set in rapid motion, to spin in the same plane,
directed, for instance, to any one star that happens at the time to be
due north or due south of us, while the frame moves round it with the
rotation of the Earth.

I think, then, on the whole, we may say that those persons who, in
the present state of our knowledge on the subject, are not convinced
that the Earth revolves on its own axis, would not be satisfied by any
evidence whatever.

Returning now to the general question of Copernicanism, we find that
for some time after the trial of Galileo, things remained much _in
statu quo_; unless we except the observation of the transit of Venus,
in 1639; but, as that eventful seventeenth century was drawing to its
close, there came on the scene some thoughtful and able astronomers,
who could not only utilise the knowledge of their predecessors, but
could also guess, with more or less accuracy, what that law--hitherto
unknown--might be, which governed the planets and our own Earth in
their movements. It was about this time that the Royal Society was
founded in London, and a stimulus was thus given to investigation and
to experiment. The third law of Kepler, which states that in all the
planetary orbits the square of the periodic time of revolution is in
a constant proportion to the cube of the mean distance, suggested the
existence of another law, not yet discovered, a law of attraction, on
which this itself depended. Among the astronomers of that day three
names deserve special mention, Wren, Hooke, and Halley, because each
of them guessed with some accuracy at the true doctrine--as it is now
known to be--that the planets are attracted to the Sun by a force which
acts inversely as the square of the distance. Hooke, in particular,
deserves the credit of having applied this law to the path of a
projectile, under certain circumstances, as well as to the planetary
orbits; but though he thus lighted upon true conclusions, he appears
to have been deficient in mathematical skill, and therefore unable to
verify his results. It is, however, only just to the memory of Horrox,
who was carried off by an early death, to mention that the true theory
of the identity of terrestrial and astronomical gravity had occurred
to his mind; if he had lived twenty or thirty years longer, he might
have survived in history as the discoverer of the great problem.

Be this as it may, there now arose another man greater than his
predecessors, and greater than all his contemporaries; he also was an
Englishman, by name Isaac Newton. What others guessed, or concluded
on insufficient evidence, became, in his powerful hands, clear and
well-grounded truths, proved, so far as such things could be proved, by
rigid mathematical reasoning, and established on a solid basis, which
time has not shaken, and which subsequent investigation has confirmed.
Others had supposed the existence of the law of attraction by which the
Sun acted on the planets; many persons had understood the existence of
terrestrial gravitation. Newton showed that these two are identical;
and, moreover, that every particle of matter attracts every other
particle _mutually_, and according to the one universal law, that of
the inverse square of the distance; so that a vast planet revolving
round the Sun obeys the same law as a pebble dropped from one’s hand to
the Earth. The popular story of his having been suddenly led to this
conclusion by the sight of an apple falling is apparently fabulous; and
what really occurred is this: he sat alone one day in a garden, and
fell into a speculation (as men of scientific mind are apt to do) on
the power of gravity, that is, of gravity as we feel it here on the
Earth. Then it struck him that however high you ascend, even on the
loftiest mountains, no sensible diminution in this remarkable force
takes place; so, he said to himself: why not as high as the Moon? If
so, perhaps she is retained in her orbit by this very power. And again
if so, what then? To which question his active mind gave the just and
true answer, that it was probably one and the same force that acted at
the surface of the Earth, at the distance of the Moon, and finally, as
regulating the action of the Sun on the planets.

It seems that there was an error, which it is unnecessary to explain in
detail, in Newton’s first calculations; but that when, after a lapse of
time and with the error corrected, he again returned to them, he found
the motion of the Moon to be exactly accounted for by his theory.

Again, in dealing with the complicated problem of the action of the
heavenly bodies one upon the other, that is, when the disturbing force,
for instance, of a third body is brought to bear on the motions of
two others, although Hooke and others had as a conjecture put forth
the existence of such mutual action, yet Newton was the first who
thoroughly grappled with it.

The mutual attraction of matter, so far as things terrestrial are
concerned, had occurred to the inquiring intellect of Francis Bacon;
but it was left for Newton to propound it as the great principle that
governs the physical universe.

Now let us see how all this bears on the truth of the Copernican
system. Newton proved--and I may add that the improved methods of
mathematics which have been adopted since his day make the proofs more
simple and easy--that if any body moves in an ellipse, or indeed, in
one of the other conic sections, the law of force, tending to the
focus, is that of the inverse square of the distance.[26] Conversely,
he proved that a body under the action of a central force, varying in
intensity as the inverse square of the distance, will move in a conic
section.

Then if the Moon moved in an ellipse, as it was easy to perceive that
she did, and if her motion corresponded precisely with what it would
be on the theory of universal gravitation; if also, as seemed evident,
the planets revolved in ellipses, then the inference that the law
of gravitation, as stated by Newton, was true became irresistible;
not susceptible, as before stated, of direct and absolute proof, but
established conclusively by a sound and legitimate induction.

What I have just stated shows that Kepler’s first law corresponds
with Newton’s discovery; but the same is true of the two other laws.
It would of course be out of place here to go minutely into all the
evidence which can be gathered in support of the doctrine of universal
gravitation. I may briefly state that all of Kepler’s laws are
simply explicable by that hypothesis, and that the evidence derives
additional confirmation from the following curious fact: observation
shows that Kepler’s laws, though approximately true, are not strictly
and accurately so; if the planets were mere particles revolving round
the Sun, they would then be quite rigidly true, but the planets have
a certain mass (though very small compared to the Sun) and so do in
some measure attract the Sun as well as being attracted by him, and
they, moreover, exercise a disturbing influence on each other. These
perturbations, however, have been calculated, and the result is that
they agree with what ought reasonably to be expected, supposing the
theory of universal gravitation to be true. This confirmatory proof has
been acquired, I need not add, since the time of Newton by the labours
of astronomers, Laplace and others, who have succeeded him, and who
have had the advantage of that more manageable method of mathematical
calculation to which I have just alluded.

Supposing then the law of gravitation to be established by sufficient
proof, we may now ask what must become of the old systems of
astronomy? What must befall Ptolemy and even Tycho Brahé?

It is obvious that they could do nothing but collapse. If the law
of gravitation were once admitted to be true, the idea of the Sun
revolving round the Earth must be dismissed as impossible. Here it is
right to remark that (assuming the law of universal gravitation) it
is not, strictly and scientifically speaking, correct to say that any
one heavenly body revolves round another, but that they both revolve
round their common centre of gravity. In the case of the Earth and the
Sun, so vastly superior is the mass of the latter that the centre of
gravity is far away within his volume, and the disturbance exercised
on him by the Earth is scarcely appreciable; so also, in the case of
the Moon and the Earth, the centre of gravity is within the latter,
but at a considerable distance from its own centre; and here there is
a distinctly appreciable oscillation of the Earth, arising from this
very cause, during each revolution of the Moon in her orbit. When two
bodies are more nearly equal in mass, as is probably the case with the
double stars that have been observed in recent times, then the two
revolve round a centre of gravity lying between them, exterior to both
of them. It is believed that this is actually the fact in the instance
I am here alluding to of the double stars, and there is some reason for
supposing that the curve in which they revolve is an ellipse. This, if
true, would clearly indicate that the law of gravitation, as stated by
Newton, extends not only through our own solar system, but over the
whole material universe.

And there is one remarkable property of this mysterious agency which
we term gravitation, and that is its instantaneous action even at the
greatest distances. Light travels with an enormous and yet a finite
velocity, so that it takes a few years to arrive at the Earth from even
the nearest stars. The force of gravity knows no such limit, nor is its
action retarded by even the minutest fraction of time.

Nor, again, is it impeded, as in the case of light, by any screen or
obstacle of whatever nature. Furthermore, it does not lose anything of
its intensity, as light does, by being diffused over a larger surface;
it varies as the _mass_ of the bodies concerned, but not in the least
according to the extent of their surfaces. Given the same distance, no
diffusion weakens its force.

Great as was the evidence adduced by Newton for the truth of his
theory, there were some real difficulties in the way of its reception.
I need not allude to these in detail; they are explained in treatises
on physical astronomy for the benefit of those who are interested in
the subject. Briefly, I may say that subsequent research and careful
calculations have removed the difficulties, and thereby confirmed the
already existing evidence.

Then, as regards terrestrial gravity, experiments have been
made--notably at the mountain Schehallion, in Scotland--throwing
additional light upon it, and indicating that not merely the Earth as a
whole, but any great mass, such as a mountain, exercises an appreciable
attractive force.

Newton seems to have expected that some further discovery would take
place, at no distant period, as to the nature of this occult agency
which operates so powerfully in the heavens and on the Earth. In one
of his letters he strongly disclaims the opinion that gravity is
essential to matter and inherent in it; he thinks it is “inconceivable
that inanimate brute matter should, without the mediation of something
else which is not material, operate on and affect other matter
without mutual contact... that gravity should be innate, inherent,
and essential to matter, so that one body may act upon another at a
distance through a _vacuum_, without the mediation of anything else by
and through which their action and force may be conveyed from one to
another, is to me so great an absurdity that I believe no man who has
in philosophical matters a competent faculty of thinking can ever fall
into it.”

And yet we see that what he thought absurd is still apparently true,
and that, great as was Newton’s sagacity in discovering and proving the
effects of this great cosmical law, he failed when he came to speculate
on the more remote causes of it. Since his time, other ingenious
theorists have imagined hypotheses in the hopes of accounting for it;
but their efforts have not met with any great success, and the last
word of science on the subject is that the cause of gravitation remains
undiscovered.

But if the attempt to trace the ultimate cause of the law of
gravitation has been a failure, the proof of its operation in the
physical universe has been a marvellous success, and that not only in
the present day, when difficulties have been removed and fresh evidence
has been added, but, to a certain extent, even in Newton’s own time,
and especially here in his own country. Indeed, we cannot suppress a
feeling of admiration when we contemplate the revolution in astronomy
brought about by this quiet, unobtrusive man, who is said to have spent
thirty-five years of his long life within the walls of Trinity College,
Cambridge, of which he was a Fellow, and who, though twice elected to
represent the University in Parliament, never opened his lips in the
House of Commons. I may, perhaps, be here permitted to insert a passage
from a work to which I have previously alluded, Whewell’s “History of
the Inductive Sciences,” well worth quoting both for its eloquence and
its truth. After recounting, with some detail, the circumstances of
this great epoch in astronomical knowledge, he proceeds:

    Such, then, is the great Newtonian induction of universal
    gravitation, and such its history. It is indisputably and
    incomparably the greatest scientific discovery ever made,
    whether we look at the advance which it involved, the extent
    of the truth disclosed, or the fundamental and satisfactory
    nature of this truth. As to the first point, we may observe
    that any one of the five steps into which we have separated
    the doctrine [these were, 1st, that the force attracting
    _different_ planets to the sun, and, 2nd, the force attracting
    the _same_ planet in different parts of its orbit, is as the
    inverse square of the distances; 3rd, that the earth exerts
    such a force on the moon, and that this is identical with
    terrestrial gravity; 4th, that there is a _mutual_ attraction
    of the heavenly bodies on one another; 5th, that there exists
    a mutual attraction of _all particles of matter_ throughout
    the universe] would of itself have been considered as an
    important advance, would have conferred distinction on the
    persons who made it, and the time to which it belonged. All the
    five steps made at once formed not a leap, but a flight; not
    an improvement merely, but a metamorphosis; not an epoch, but
    a termination. Astronomy passed at once from its boyhood to
    mature manhood. Again, with regard to the extent of the truth,
    we obtain as wide a generalisation as our physical knowledge
    admits when we learn that every particle of matter, in all
    times, places, and circumstances, attracts every other particle
    in the universe by one common law of action. And by saying
    that the truth was of a fundamental and satisfactory nature, I
    mean that it assigned, not a rule merely, but a cause, for the
    heavenly motions; and that kind of cause which most eminently
    and peculiarly we distinctly and thoroughly conceive, namely,
    mechanical force. Kepler’s laws were merely _formal_ rules,
    governing the celestial motions according to the relations
    of space, time, and number; Newton’s was a _causal_ law,
    referring these motions to mechanical reasons. It is no doubt
    conceivable that future discoveries may both extend and further
    explain Newton’s doctrines; may make gravitation a case of
    some wider law, and may disclose something of the way in which
    it operates--questions with which Newton himself struggled.
    But, in the meantime, few persons will dispute that, both in
    generality and profundity, both in width and depth, Newton’s
    theory is without a rival or neighbour.[27]

The effect of all this on the Copernican system and the evidence on
which it rested, was to raise that system from a simple though strong
probability, a question on which at any rate something might be said
for and against it, to a probability of almost overwhelming force; for
it not only showed how the heavenly bodies moved, but it explained the
cause of their motions, and in a word furnished the key that unlocked
the arcana of Nature. When you came to know not only how the Moon and
the planets moved, but the law which regulated their movements, and
when you found that all fitted into one harmonious whole (at least with
some minor exceptions), it was not easy to refuse assent to a theory
supported by such powerful evidence.

Yet in saying this we are perhaps rather viewing the question from
our present standpoint, than as a contemporary would have done. As
a matter of fact, Newton’s hypothesis, though eagerly received in
England, met with a long opposition on the Continent, and particularly
in France, where Descartes’ theory of vortices reigned supreme for many
years. It must not be supposed that these Cartesian philosophers were
anti-Copernicans; far otherwise, only they accounted for the celestial
motions in a different way from Newton, and, as every one now admits,
in a wrong way.

I have already remarked that there were some apparent difficulties in
the application of the law of universal gravitation to all the heavenly
bodies, and that these have been removed by subsequent calculation. One
of these difficulties, if indeed it could be so called (for it hardly
amounted to that), has been solved within living memory. It was noticed
that the planet Uranus showed signs of perturbation from some unknown
reason; and even the work I have just quoted, “Whewell’s History of
the Inductive Sciences,” published in 1847, contains the following
sentence: “Uranus still deviates from his tabular place, and the cause
remains yet to be discovered.” Two astronomers, one French and one
English, Le Verrier and Adams, found out the cause by discovering the
existence, each independently of the other, of an exterior planet
revolving in an orbit more distant by far than that of Uranus; to this
planet the name of Neptune has been given, and his existence is one
more confirmatory proof of the theory of gravitation.

The Copernican system had been built up and consolidated by Newton’s
great discovery; but another piece of evidence, of a most important
character, was added by the investigations of Bradley, Professor of
Astronomy at Oxford, and afterwards Astronomer Royal; this careful
observer, while engaged in endeavouring to detect such an apparent
motion of the fixed stars (so called) as would indicate an annual
parallax, noticed that another motion existed different from that
which the annual parallax would produce, and for which he could not
account; the apparent orbits described by the stars observed depended
on the distance of the stars from the pole of the ecliptic; the
phenomenon was different from anything hitherto discovered, and one
or two modes of explanation were tried in vain. Accident, however,
turned Bradley’s thoughts in the right direction; he was one day in
a boat on the Thames, and observed that the vane on the mast gave a
different apparent direction to the wind, according as the boat sailed
in different courses. Here, then, was the solution of the difficulty:
it was already known from Römer’s investigations that light moved with
a finite velocity, and if so it would naturally produce the same effect
as that observed in the boat, or to take an illustration very commonly
given, like that which any one finds when moving along rapidly in a
shower of rain, in which latter case the rain seems to fall not in the
direction it has when one is at rest, but in a direction compounded of
that and the one opposite to the person’s line of motion.

Bradley soon drew the correct conclusion, that light acted in precisely
the same way upon the Earth as it moved in its orbit, and that the
_apparent_ annual displacement of the stars, as detected by him, arose
from this sole cause. All the great astronomers who followed him have
agreed with his conclusions, and the phenomenon in question, which is
called the aberration of light, has conferred a lasting fame on its
discoverer. And the remarkable point about it is this, that not only
does it give a fresh illustration to the Copernican theory, but it
is one of the very few scientific facts that cannot (so far as our
knowledge of the subject goes) be explained in any other way. It is,
therefore, generally considered as a critical test of the truth of the
system.

There are two other phenomena, on which however I do not propose to
dwell at any length, known as precession and nutation, which it is
not easy to explain otherwise than by the modern theory of astronomy
and the principle of gravitation; the latter of these two owed its
discovery to Bradley, and the former to Hipparchus, who could not have
been aware of its real cause, though he had observed the fact of its
occurrence.

But passing on from these, I may call attention to one most remarkable
result of modern scientific research, connected with the stars. In
Galileo’s day, it was a drawback to the Copernican theory that none of
the stars showed the smallest annual parallax; in popular language,
none of them seemed to undergo any change of place, however small,
when observed at opposite points of the Earth’s orbit, or as the
opponents would have said, the Earth’s imagined orbit. A displacement
of this kind, I need hardly repeat, must not be confounded with that
other motion which Bradley observed and explained. This was one of
Tycho Brahé’s reasons for rejecting the Copernican system, and it
was one of the best arguments used by the opponents of Galileo. As
the enormous distance of the stars from the Earth was, as we have
already seen, at that time unknown, the celestial distances generally
being under-estimated even by the best astronomers, the argument had
an apparent force, which no one now would attribute to it. Galileo
himself had some hope of overcoming the difficulty by discovering some
annual displacement in certain stars, but it is needless to add that
his instruments were unequal to such a task. Subsequent observers
tried various methods, but without any real success until the present
century, when Bessel and other observers found that a star called
61 Cygni had a certain annual parallax; and not long afterwards,
Henderson, making his observations at the Cape of Good Hope on a
conspicuous star in the constellation of the Centaur, a constellation
belonging to the southern hemisphere, found at length that this star,
which in fact is a double star, and known as α Centauri, had a parallax
of nearly 1″; subsequent calculations show it to be probably rather
less, that is to say about 0″·91. This means that it is more than
twenty billions of miles distant, and that light takes more than three
years to travel from α Centauri to the earth. It is, however, believed
to be much the nearest of all the stars, no other coming within double
of the distance.

Now it is difficult to evade the conclusion which naturally follows
from these results, that the Earth really does move in an annual orbit
round the Sun. It is no part of my present task to give a list of the
stars of which the parallax has been found, but I may say there are
several others besides the two I have named; and I know of no method
of accounting for the fact in any way but by the annual motion of the
Earth, unless we suppose some instrumental error to have occurred.
There have been so many of these in times past that it may seem rash to
exclude such a possibility, but, considering the perfection of modern
scientific instruments, it is in the highest degree improbable; and we
may fairly reckon the parallaxes of the stars as a strong confirmation
of the already strong evidence in favour of the Copernican theory--a
theory which, as we have seen, was, from a purely scientific point of
view, very probable in the days of Galileo, overwhelmingly probable
after the great discovery of Newton, and at the present time, with all
the light that subsequent research and observation have thrown on it,
scarcely short of a moral certainty.

I may repeat once more that it has not, indeed, that absolute physical
certainty, arising from direct experiment, which has been obtained in
other scientific investigations; but, allowing for this faint element
of instability, we may fairly say that no truth of natural philosophy
stands on a firmer basis.

And for Galileo, who lived before the day when, as Whewell says,
“Astronomy passed from boyhood to mature manhood,” we may fairly say
that, after we have censured his faults and his errors, after we have
ascertained that he was not a hero or a “martyr of science,” we must
still recognise the fact that he was one of the greatest natural
philosophers of his day, pre-eminent in astronomy, in mechanics,
in mathematics. To his honour also be it added, that his religious
faith, and his respect for the Church and her authority, so far as we
can judge, never failed. Whatever his defects may have been--want of
prudence, want of candour, want of consideration for others--we can
easily perceive that he would never have been willingly drawn into any
controversy intended to provoke antagonism between Religion and Science.

In the present age, unhappily, there have been men who have taken
the other course, and have contributed their share towards exciting
antagonism, heedless of the consequences. Some have done this
unwittingly, arguing on the side of religion, but without a proper
supply of sound scientific information; others, on the opposite
side, have shown so bitterly hostile a spirit to Revelation, if not
even to Natural Religion, as to render it more than ever difficult
to re-establish that concord between the two studies, that of the
supernatural and that of the physical, which should never have been
interrupted.

This, however, is so wide a subject that I must not be led into it. Yet
I may briefly remark that two of the greatest lights of the Catholic
Church, men whose teaching and whose writings have exercised an undying
influence, have both, either by words explicitly, or implicitly by
their example, contributed to encourage a sound knowledge of natural
philosophy, and in harmony with Christian theology.

They both lived when physical science was in its infancy, though at
intervals of nearly 800 years apart. St. Augustine, who flourished
towards the latter part of that period dominated by the corrupt
civilisation of ancient Rome, amongst his voluminous works devoted
one treatise to the interpretation of the Book of Genesis, “De Genesi
ad Litteram;” and he takes the opportunity of cautioning those whom
he addresses against the risk of exciting the ridicule of unbelievers
by a mistaken adherence to a rigidly literal interpretation of Holy
Scripture. He was, I believe, one of the first that interpreted the six
days of Creation in the non-literal sense, though his particular theory
is not one in accordance with modern scientific opinion. I allude to
him not for the details of natural philosophy, but as enunciating a
principle, which some subsequent authors have not followed as they
might have done.

St. Thomas Aquinas lived in those middle ages of which he was one of
the most brilliant ornaments. The power of his intellect is admitted by
those who have little sympathy with his teaching; his literary industry
is a standing marvel; and I have already observed that besides the
theological and metaphysical works on which he expended so much labour,
he wrote a treatise on the astronomy of Aristotle. It may be said this
is no very great matter, but I mention it as illustrating the breadth
of mind of this great saint and theologian, who could spare time for
a study of physical science without neglecting the more solemn duties
of his calling. His active mind was alive to every source from whence
wisdom and learning could be imbibed; and if he had lived in the age of
Galileo, I have sometimes fancied that he would have thrown some oil on
the troubled waters, would have counselled prudence to the adventurous
astronomer, patience and forbearance to his antagonists. But it is of
no avail to indulge in speculations such as these. Each age of the
world has its difficulties, moral and intellectual, and we can neither
hurry the stream of human thought onwards nor drive it backwards.

So again it is with the dispositions of individuals; if Galileo had
been gifted with the calm, dignified reserve of Newton, instead of
being the vivacious, loquacious Italian that he in fact was, he might
have lived and died in peace.

And now, if I may be permitted to recur once more to the subject of
gravitation, I have a word to say as to the lesson which this great
all-pervading law seems to teach. It has nothing to do with any
question of revealed Religion; but does it not bear the unmistakable
signs of the action of an all-wise, an all-powerful Creator? It may
possibly be the result of some other, though unknown, law; and even
then it brings us back to the same point. The result in nature remains
the same, and that result is written in characters that cannot be
ignored. Mathematicians have occupied themselves in making suppositions
as to the effects of imaginary laws of gravity, some of which might,
no doubt, ensure sufficient order and regularity to maintain this
world, and the countless worlds that people space, while others would
cause hopeless confusion. The striking thing is that the existing law
perfectly answers its purpose.

Only let us imagine that no law of attraction acted upon matter at all,
nor any force of whatever kind--what would be the result? There would
be no coherence, no abode for human or animal life--nothing but chaos
and anarchy.

If, then, we contrast this imagined picture with the one actually
before us, we are, I think, forcibly led to the conclusion that the
physical universe owes its origin, its existence, its harmony to an
Omnipotent Being, unseen, yet not unknown, intangible to the senses,
ever present to the intelligence.

And now, in order to avoid misapprehension, I venture to restate
briefly the propositions I have sought to establish.

I have maintained that the Catholic Church has a right to lay her
restraining hand on the speculations of Natural Science, just as much
as she has in the case of other speculative inquiries. Those who do
not believe in her prerogatives will, of course, deny such right _in
toto_; but I contend that if you grant the existence of this right at
all, you cannot exclude Physical Science from its operation.

On the other hand, in the particular case of Galileo, I have not
attempted to defend all the proceedings of the Cardinals of the Index
and the Cardinals of the Inquisition. For it must be remembered
it was no gentle rebuke with which the Copernican system and the
individual Galileo were visited; no such light condemnation as that
of placing on the Index of prohibited books all Copernican works as
being _inopportune_, or again, that of a caution to Galileo to be more
prudent, was deemed adequate to the emergency--if, indeed, any one even
thought of them.

So with the facts of the history before us, I think any sweeping
defence of the proceedings in question would be unnecessary from an
ecclesiastical point of view, and from a scientific point of view
untenable.

Moreover, I must add, as an indispensable premiss to the conclusion
just stated, I have also maintained that the censures pronounced by
the Cardinals on both occasions were not dogmatic decisions, such
as Catholic theologians hold to be infallible; but disciplinary
enactments, varying with the changing characters of different ages.

Then again, referring to the scientific questions involved, we may
see that Astronomy, considered historically, is divided into three
periods--the ancient one before the invention of the telescope, that
is, up to the time of Galileo; the intermediate one, when the telescope
was in use but the law of universal gravitation as yet unknown--from
Galileo until the publication of the “Principia” of Newton; and the
modern one, from Newton downwards. During the first period it seemed
highly probable to the whole world, with the exception of a few gifted
intellects, that this Earth was the centre of the Universe, and that
all the heavenly bodies revolved round it; during the second period,
when the telescope had shed a light so powerful and so brilliant upon
astronomical research that men could not absolutely close their eyes
to it even if they wished, the balance of probability passed into the
opposite scale, and the more intelligent men of science guessed at the
truth, however indistinctly. But some elements of uncertainty remained;
and this circumstance, taken in connection with the irrelevant
arguments so much in vogue at that time, must in all fairness be
allowed as an excuse for the many good men, ecclesiastics and others,
who opposed the Copernican doctrine. After the great step made by
Newton it was no longer a question of balancing probabilities, for the
weights were almost all transferred to one scale, and the probabilities
of the truth of the Heliocentric System (to give it for once its
accurate name) became overwhelming. The subsequent investigations
of Bradley and others have gone further still, and have converted
this strong, overpowering probability into something approaching
indefinitely near to a moral certainty.

Beyond this we cannot reasonably expect to go; _physical_ certainty
is not to be attained when we have to traverse the vast distances of
celestial space, and human infirmity must be content to recognise the
boundary beyond which it may not pass, the limit imposed on finite
minds by the Infinite.


THE END.


CHARLES DICKENS AND EVANS, CRYSTAL PALACE PRESS




FOOTNOTES


[1] Nicetas of Syracuse (whose date I am not able to give) seems to
have been aware of the diurnal movement of the earth round its axis.

[2] M. de l’Épinois has, since then, published a still more complete
collection of the various documents he had obtained permission to
inspect at Rome; but this work is, unfortunately, out of print.

[3] “Principium 7^m.--Sancta Sedes Apostolica cui divinitus commissa
est custodia depositi, potestas pascendi universam Ecclesiam ad salutem
animarum, potest sententias theologicas vel quatenus cum theologicis
nectuntur proscribere ut sequendas vel proscribere ut non sequendas,
non unice ex intentione definitivâ sententiâ infallibiliter decidendi
veritatem, sed etiam absque ilia ex necessitate et intentione vel
simpliciter vel pro determinatis adjunctis prospiciendi _securitati_[4]
doctrinæ Catholicæ. In hujusmodi declarationibus licet non sit
doctrinæ _veritas infallibilis_, quia hanc decidendi ex hypothesi
non est intentio; est tamen _infallibilis securitas_. Securitatem
dico tum objectivam doctrinæ declaratæ [vel simplicitea vel pro
talibus adjunctis], tum subjectivam quatenus omnibus tutum est eam
amplecti, et tutum non est, nec absque violatione debitæ submissionis
erga magisterium divinitus constitutum fieri potest, ut eam amplecti
recusent.

“Coroll. C. Falsum est, auctoritatem propter quam debeatur assensus
intellectus, solam esse auctoritatem Dei revelantis seu Ecclesiæ vel
Pontificis infallibiliter definientis; sunt enim gradus assensus
religiosi multiplices. In præsenti distinguendus est assensus _fidei
proprie et immediate divinæ_ propter auctoritatem Dei revelantis;
assensus fidei quam supra diximus _mediate divinam_ propter
auctoritatem infallibilitur definientis doctrinam ut veram non tamen
ut revelatam; assensus _religiosus_ propter auctoritatem universalis
providentiæ ecclesiasticæ in sensu declarato.”--_De Divina Traditione
et Scriptura_, p. 116, et seq. Ed. 1870.

[4] “Non coincidere hæc duo, infallibilem veritatem et securitatem,
manifestum est vel ab eo, quod secus nulla doctrina probabilis aut
probabilior posset dici sana et secura.”

[5] It happens, curiously enough, that the doctrine of the perfect
immobility of the Sun, which so shocked the Qualifiers of the
Inquisition, is simply discarded by modern astronomers. No one now
holds that the Sun is the centre of the whole universe, or that he is
immovable. It is generally supposed that he travels in space, though
not round any _known_ centre, and the Earth and Planets with him.

[6] “Dico, che quando ci fosse vera dimostratione che il Sole stia nel
centro del mondo, e la terra nel 3 cielo, e che il Sole non circonda la
terra, ma la terra circonda il Sole, allora bisogneria andar con molta
consideratione in esplicare le Scritture che paiono contrarie, e più
sotto dire che non l’ intendiamo, che dira che sia falso quello che si
dimostra. Ma io non crederò che ci sia tale dimostratione fin che non
mi sia mostrata, etc.”--_Extract from Cardinal Bellarmine’s Letter to
F. Foscarini._

[7] A brief but interesting résumé of the Aristotelian physics is given
in Whewell’s “History of the Inductive Sciences,” a work to which I
shall have occasion to refer more than once.

[8] It is said that a weight dropped from the top of a very high
tower falls slightly to the _east_, because the velocity of the axial
rotation is greater at the summit of the tower than at its foot, and
the stone or ball dropped partakes of the motion of the _highest_ part
of the tower from which it falls; this is perfectly true in theory;
and experiments, made not only from the summits of towers but also in
mines, tend to confirm it.

[9] Simplicio having said that the cause why parts of the earth are
carried downwards was gravity, Salviati answers: “Voi errate, Signor
Simplicio, voi dovevate dire, che ciaschedun sa, ch’ ella si chiama
gravità; ma io non vi domando il nome, ma dell’ essenza della cosa:
della quale essenza voi non sapete punto più di quello, che voi
sappiate dell’ essenza del movente le Stelle in giro; eccetuatone il
nome, che a questa è stato posto, e fatto familiare, e domestico per
la frequente esperienza, che mille volte il giorno noi ne veggiamo; ma
non è, che realmente noi intentiamo più, che principio, o che virtù
sia quella, che muove la pietra in giù, di quel noi sappiamo chi la
muova in sù, separata del proiciente; o chi muova la Luna in giro,
eccettochè (come ho detto) il nome, che più singolare e proprio gli
abbiamo assegnato di gravità; dovechè a quello con termine più generico
assegniamo virtù impressa, a quello diamo intelligenza o assistente, o
informante; e a infiniti altri moti diamo loro per cagione la natura.”

[10] It is curious that the notion of the universe being shaped
as a curve returning into itself has been started by some modern
German philosophers, founders of what has been called “non-Euclidian
geometry.” The investigations of astronomers, however, rather point to
the conclusion that the stellar universe has no centre, no symmetrical
figure, though speculations such as these must always be uncertain.

[11] To speak of the circumference of a circle of infinite radius as
being identical with a straight line (though practically true enough)
is not rigidly accurate. We should say that they approximate infinitely
to one another, or in mathematical phraseology, they are equal to each
other _in the limit_.

[12] It is not intended here to deny what some writers state--that
the _friction_ caused by the Earth’s rotation does in some degree act
upon the tidal wave. It is remarkable, so far as can be ascertained
from observations taken at some small island at a distance from any
continent, that the tidal wave of the Ocean only rises, even at the
spring, about five or six feet. The enormous rise of water at some
places arises from the tidal wave being driven into estuaries, mouths
of rivers, and other narrow channels.

[13] These are the author’s words, spoken by Salviati: “Tra tutti
gli nomini grandi, che sopra tal mirabile effetto di natura hanno
filosofato, più mi maraviglio del Keplero, che di altri, il quale
d’ingegno libero, e acuto, e che aveva in mano i moti attribuiti alla
terra, abbia poi dato l’orecchio, e assenso a _predominii della Luna
sopra l’acqua_, e a proprietà occulte, e simili fanciullezze.”

[14] It is not intended to imply that these two Schools of thought
stand on anything like the same scientific level.

[15] The spots on the Sun were seen at about the same period of time by
Fabricius and by Father Scheiner, a Jesuit, as already mentioned.

[16] I must not be understood as implying that even doctrinal decisions
promulgated by the Roman Congregations _in their own name_ are
considered by theologians to be infallible; such character belonging
only to decisions addressed by the Pope himself to the Church.

[17] A curious instance of popular unacquaintance with astronomy was
afforded some months ago, when the planet Venus, which one would think
was a well-known object to most people, was mistaken for “the Star of
Bethlehem;” and this mistake was by no means confined to the ignorant,
but was shared by persons of education.

The planet was at the time a brilliant “morning star;” and the effect
on the eye is more striking in these circumstances than when it is
seen, as is very commonly the case, in the evening, shortly after
sunset. I suppose this would account in some measure for the delusion.

In clearer and finer skies than those of England, Venus is sometimes so
brilliant in the early morning as to startle an unaccustomed observer.

[18] Dr. Ward makes a curious mistake in one point; he speaks in one
of the articles of _The Dublin Review_ (which he then edited) of
Copernicanism as destroying the old ideas as to _above and below_;
that is to say, for instance, your idea of ascending on high towards
heaven was thereby nullified, and ascending from the surface of the
earth meant going in any direction which the earth’s rotation might
place above your head at any particular moment. But Dr. Ward, who
was doubtless thinking of the very old and exploded notion that the
earth was a flat surface, does not seem to have been aware that this
objection applies in principle to the Ptolemaic system also; Ptolemy
knew that the earth was spherical in its shape, and consequently that
what would be _above_ a person in the eastern parts of India, to take
an example, would be widely different from that which would be so at
the westernmost point of Africa. It may, however, be admitted that an
additional cause for bewilderment was presented by the diurnal rotation
of the Earth, since it then appeared that the same point in space
_above_ you at noon would be far away _below_ you at midnight.

[19] Quoted from an article in the “Revue des Questions Historiques,”
1867, “Galilée, son Procès, sa Condemnation, d’après des documents
inédits,” by M. Henri de l’Épinois.

[20] Tycho Brahé discovered two out of the principal inequalities in
the Moon’s motion--known to astronomers as the Variation and the Annual
Equation; the third, which is the most obvious of all and is called the
Evection, was discovered by Ptolemy.

[21] The figurative interpretation, however, in this instance is as
old as St. Augustine, though his speculations lead him to a different
conclusion from that of modern scientific men; namely, that of
supposing the actual creation to be the work of one moment.

[22] It is, I think, Mr. Proctor who uses this argument in one of his
works, to prove how very doubtful a thing is the existence of highly
organised and rational beings on the other planets.

[23] It is quite possible, as Mr. Lockyer has recently argued, that
many objects that appear to us as stars, are in reality nebulæ in a
more or less advanced stage of condensation.

[24] The _relative_ distances could be computed geometrically, even
before the absolute distances were known, and in fact were so; Kepler’s
third law affords a simple rule for calculating them, but they were
known even previously.

[25] I may, perhaps, be permitted to recall to the reader’s mind, in a
note, one or two of the main objections urged by the anti-Copernicans.
One of these was that it would leave the atmosphere behind, the true
answer to which is that the atmosphere itself is attracted by the
force of gravity to the earth, and is carried round by the rotation,
as everything else is; this Galileo did not perfectly understand, as
may be seen by his remarks, both in the second and the fourth day’s
dialogue. Another was this--and it was put forward by no less a man
than Tycho Brahé--a stone dropped from a high tower ought to fall to
the westward of the tower, because the tower would be carried on to the
east by the earth’s rotation, and the stone would not; this, however,
being contrary to experience. The real fact is that the stone partakes
of the rotatory movement as much as the tower does, the two forces of
rotation and gravity being combined according to the second law of
motion, while the stone is falling; this Galileo did know. Supposing
a very high tower, the stone ought to fall slightly to the east, on
account of the superior velocity of rotation at the top of the tower to
that at the bottom. It is said this experiment has been successfully
tried, as stated in note, page 55.

[26] There are other laws, besides that of the inverse square of the
distance, which would cause a body to move in an ellipse, at least if
the force acting on it were placed, not in the focus, but in the centre
of the orbit. The question has been discussed with reference to some of
the binary stars which appear to move round one another in ellipses. No
doubt is thereby raised as to the prevalence of the law of the inverse
square in our own solar system, where it has been verified by long and
careful observation; the doubt (I think we may say a comparatively
slight one) is whether the same law extends to the whole stellar
universe, where, of course, accurate observation is impracticable.

[27] I do not think the truth of this is affected by any of the
great modern discoveries; though that of the Conservation of Energy
approaches more nearly than others to Universal Gravitation in its
importance.




Transcriber’s Notes


Punctuation, hyphenation, and spelling were made consistent when a
predominant preference was found in the original book; otherwise they
were not changed.

Simple typographical errors were corrected; unbalanced quotation
marks were remedied when the change was obvious, and otherwise left
unbalanced.

Original text uses “loadstone”, not “lodestone”.

Footnotes, originally at the bottoms of pages, have been collected and
moved to the end of this eBook.

Page 22: The symbol in “Locus sigilli” is a version of a Maltese cross.

Footnote 4, originally on page 27, is a sub-note of footnote 3.





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