Galileo Galilei
Generally called GALILEO, born at Pisa, 18 February, 1564; died 8
January, 1642. His father, Vincenzo Galilei, belonged to a noble
family of straitened fortune, and had gained some distinction as a
musician and mathematician. The boy at an early age manifested his
aptitude for mathematical and mechanical pursuits, but his
parents, wishing to turn him aside from studies which promised no
substantial return, destined him for the medical profession. But
all was in vain, and at an early age the youth had to be left to
follow the bent of his native genius, which speedily placed him in
the very first rank of natural philosophers.
It is the great merit of Galileo that, happily combining
experiment with calculation, he opposed the prevailing system
according to which, instead of going directly to nature for
investigation of her laws and processes, it was held that these
were best learned by authority, especially by that of Aristotle,
who was supposed to have spoken the last word upon all such
matters, and upon whom many erroneous conclusions had been
fathered in the course of time. Against such a superstition
Galileo resolutely and vehemently set himself, with the result
that he not only soon discredited many beliefs which had hitherto
been accepted as indisputable, but aroused a storm of opposition
and indignation amongst those whose opinions he discredited; the
more so, as he was a fierce controversialist, who, not content
with refuting adversaries, was bent upon confounding them.
Moreover, he wielded an exceedingly able pen, and unsparingly
ridiculed and exasperated his opponents. Undoubtedly he thus did
much to bring upon himself the troubles for which he is now
chiefly remembered. As Sir David Brewster (Martyrs of Science)
says, "The boldness, may we not say the recklessness, with which
Galileo insisted on making proselytes of his enemies, served but
to alienate them from the truth."
Although in the popular mind Galileo is remembered chiefly as an
astronomer, it was not in this character that he made really
substantial contributions to human knowledge, as is testified by
such authorities as Lagrange, Arago, and Delambre, but rather in
the field of mechanics, and especially of dynamics, which science
may be said to owe its existence to him. Before he was twenty,
observation of the oscillations of a swinging !amp in the
cathedral of Pisa led him to the discovery of the isochronism of
the pendulum, which theory he utilized fifty years later in the
construction of an astronomical clock. In 1588, a treatise on the
centre of gravity in solids obtained for him the title of the
Archimedes of his time, and secured him a lecture-ship in the
University of Pisa. During the years immediately following, taking
advantage of the celebrated leaning tower, he laid the foundation
experimentally of the theory of falling bodies and demonstrated
the falsity of the peripatetic maxim, hitherto accepted without
question, that their rate of descent is proportional to their
weight. This at once raised a storm on the part of the
Aristoteleans, who would not accept even facts in contradiction of
their master's dicta. Galileo, in consequence of this and other
troubles, found it prudent to quit Pisa and betake himself to
Florence, the original home of his family. By the influence of
friends with the Venetian Senate he was nominated in 1592 to the
chair of mathematics in the University of Padua, which he occupied
for eighteen years, with ever-increasing renown. He afterwards
betook himself to Florence, being appointed philosopher and
mathematician extraordinary to the Grand Duke of Tuscany. During
the whole of this period, and to the close of his life, his
investigation of Nature, in all her fields, was unwearied.
Following up his experiments at Pisa with others upon inclined
planes, Galileo established the laws of falling bodies as they are
still formulated. He likewise demonstrated the laws of
projectiles, and largely anticipated the laws of motion as finally
established by Newton. He studied the properties of the cycloid
and attempted the problem of its quadrature; while in the
"infinitesimals", which he was one of the first to introduce into
geometrical demonstrations, was contained the germ of the
calculus. In statics, he gave the first direct and entirely
satisfactory demonstration of the laws of equilibrium and the
principle of virtual velocities. In hydrostatics, he set forth the
true principle of flotation. He invented a thermometer (termometro
lento), though a defective one, but he did not, as is sometimes
claimed for him, invent the microscope.
Though, as has been said, it is by his astronomical discoveries
that he is most widely remembered, it is not these that constitute
his most substantial title to fame. In this connection, his
greatest achievement was undoubtedly his virtual invention of the
telescope. Hearing early in 1609 that a Dutch optician, named
Lippershey, had produced an instrument by which the apparent size
of remote objects was magnified, Galileo at once realized the
principle by which such a result could alone be attained, and,
after a single night devoted to consideration of the laws of
refraction, he succeeded in constructing a telescope which
magnified three times, its magnifying power being soon increased
to thirty-two. This instrument being provided and turned towards
the heavens, the discoveries, which have made Galileo famous, were
bound at once to follow, though undoubtedly he was quick to grasp
their full significance. The moon was shown not to be, as the old
astronomy taught, a smooth and perfect sphere, of different nature
to the earth, but to possess hills and valleys and other features
resembling those of our own globe. The planet Jupiter was found to
have satellites, thus displaying a solar system in miniature, and
supporting the doctrine of Copernicus. It had been argued against
the said system that, if it were true, the inferior planets, Venus
and Mercury, between the earth and the sun, should in the course
of their revolution exhibit phases like those of the moon, and,
these being invisible to the naked eye, Copernicus had to advance
the quite erroneous explanation that these planets were
transparent and the sun's rays passed through them. But with his
telescope Galileo found that Venus did actually exhibit the
desired phases, and the objection was thus turned into an argument
for Copernicanism. Finally, the spots on the sun, which Galileo
soon perceived, served to prove the rotation of that luminary, and
that it was not incorruptible as had been assumed.
Prior to these discoveries, Galileo had already abandoned the old
Ptolemaic astronomy for the Copernican. but, as he confessed in a
letter to Kepler in 1597, he had refrained from making himself its
advocate, lest like Copernicus himself he should be overwhelmed
with ridicule. His telescopic discoveries, the significance of
which he immediately perceived, induced him at once to lay aside
all reserve and come forward as the avowed and strenuous champion
of Copernicanism, and, appealing as these discoveries did to the
evidence of sensible phenomena, they not only did more than
anything else to recommend the new system to general acceptance,
but invested Galileo himself with the credit of being the greatest
astronomer of his age, if not the greatest who ever lived. They
were also the cause of his lamentable controversy with
ecclesiastical authority, which raises questions of graver import
than any others connected with his name. It is necessary,
therefore, to understand clearly his exact position in this
regard.
The direct services which Galileo rendered to astronomy are
virtually summed up in his telescopic discoveries, which,
brilliant and important as they were, contributed little or
nothing to the theoretical perfection of the science, and were
sure to be made by any careful observer provided with a telescope.
Again, he wholly neglected discoveries far more fundamental than
his own, made by his great contemporary Kepler, the value of which
he either did not perceive or entirely ignored. Since the first
and second of his famous laws were already published by Kepler in
1609 and the third, ten years later, it is truly inconceivable, as
Delambre says, that Galileo should not once have made any mention
of these discoveries, far more difficult than his own, which
finally led Newton to determine the general principle which forms
the very soul of the celestial mechanism thus established. It is,
moreover, undeniable, that the proofs which Galileo adduced in
support of the heliocentric system of Copernicus, as against the
geocentric of Ptolemy and the ancients, were far from conclusive,
and failed to convince such men as Tycho Brah� (who, however, did
not live to see the telescope) and Lord Bacon, who to the end
remained an unbeliever. Milton also, who visited Galileo in his
old age (1638), appears to have suspended his judgment, for there
are passages in his great poem which seem to favour both systems.
The proof from the phenomenon of the tides, to which Galileo
appealed to establish the rotation of the earth on its axis, is
now universally recognized as a grave error, and he treated with
scorn Kepler's suggestion, foreshadowing Newton's establishment of
the true doctrine, that a certain occult influence of the moon was
in some way responsible. In regard to comets, again, he maintained
no less erroneously that they were atmospheric phenomena, like
meteors, though Tycho had demonstrated the falsity of such a view,
which was recommended only as the solution of an anti-Copernican
difficulty.
In spite of all deficiency in his arguments, Galileo, profoundly
assured of the truth of his cause, set himself with his habitual
vehemence to convince others, and so contributed in no small
degree to create the troubles which greatly embittered the latter
part of his life. In regard to their history, there are two main
points to be considered. It is in the first place constantly
assumed, especially at the present day, that the opposition which
Copernicanism encountered at the hands of ecclesiastical authority
was prompted by hatred of science and a desire to keep the minds
of men in the darkness of ignorance. To suppose that any body of
men could deliberately adopt such a course is ridiculous,
especially a body which, with whatever defects of method, had for
so long been the only one which concerned itself with science at
all. It is likewise contradicted by the history of the very
controversy with which we are now concerned. According to a
popular notion the point, upon which beyond all others churchmen
were determined to insist, was the geocentric system of astronomy.
Nevertheless it was a churchman, Nicholas Copernicus, who first
advanced the contrary doctrine that the sun and not the earth is
the centre of our system, round which our planet revolves,
rotating on its own axis. His great work, "De Revolutionibus
orblure coelestium", was published at the earnest solicitation of
two distinguished churchmen, Cardinal Schxxxxxmberg and Tiedemann
Gi�se, Bishop of Culm. It was dedicated by permission to Pope Paul
III in order, as Copernicus explained, that it might be thus
protected from the attacks which it was sure to encounter on the
part of the "mathematicians" (i.e. philosophers) for its apparent
contradiction of the evidence of our senses, and even of common
sense. He added that he made no account of objections which might
be brought by ignorant wiseacres on Scriptural grounds. Indeed,
for nearly three quarters of a century no such difficulties were
raised on the Catholic side, although Luther and Melanchthon
condemned the work of Copernicus in unmeasured terms. Neither Paul
III, nor any of the nine popes who followed him, nor the Roman
Congregations raised any alarm, and, as has been seen, Galileo
himself in 1597, speaking of the risks he might run by an advocacy
of Copernicanism, mentioned ridicule only and said nothing of
persecution. Even when he had made his famous discoveries, no
change occurred in this respect. On the contrary, coming to Rome
in 1611, he was received in triumph; all the world, clerical and
lay, flocked to see him, and, setting up his telescope in the
Quirinal Garden belonging to Cardinal Bandim, he exhibited the
sunspots and other objects to an admiring throng.
It was not until four years later that trouble arose, the
ecclesiastical authorities taking alarm at the persistence with
which Galileo proclaimed the truth of the Copernican doctrine.
That their opposition was grounded, as is constantly assumed, upon
a fear lest men should be enlightened by the diffusion of
scientific truth, it is obviously absurd to maintain. On the
contrary, they were firmly convinced, with Bacon and others, that
the new teaching was radically false and unscientific, while it is
now truly admitted that Galileo himself had no sufficient proof of
what he so vehemently advocated, and Professor Huxley after
examining the case avowed his opinion that the opponents of
Galileo "had rather the best of it". But what, more than all,
raised alarm was anxiety for the credit of Holy Scripture, the
letter of which was then universally believed to be the supreme
authority in matters of science, as in all others. When therefore
it spoke of the sun staying his course at the prayer of Joshua, or
the earth as being ever immovable, it was assumed that the
doctrine of Copernicus and Galileo was anti-Scriptural; and
therefore heretical. It is evident that, since the days of
Copernicus himself, the Reformation controversy had done much to
attach suspicion to novel interpretations of the Bible, which was
not lessened by the endeavours of Galileo and his ally Foscarini
to find positive arguments for Copernicanism in the inspired
volume. Foscarini, a Carmelite friar of noble lineage, who had
twice ruled Calabria as provincial, and had considerable
reputation as a preacher and theologian, threw himself with more
zeal than discretion into the controversy, as when he sought to
find an argument for Copernicanism in the seven-branched
candlestick of the Old Law. Above all, he excited alarm by
publishing works on the subject in the vernacular, and thus
spreading the new doctrine, which was startling even for the
learned, amongst the masses who were incapable of forming any
sound judgment concerning it. There was at the time an active
sceptical party in Italy, which aimed at the overthrow of all
religion, and, as Sir David Brewster acknowledges (Martyrs of
Science), there is no doubt that this party lent Galileo all its
support.
In these circumstances, Galileo, hearing that some had denounced
his doctrine as anti-Scriptural, presented himself at Rome in
December, 1615, and was courteously received. He was presently
interrogated before the Inquisition, which after consultation
declared the system he upheld to be scientifically false, and
anti-Scriptural or heretical, and that he must renounce it. This
he obediently did, promising to teach it no more. Then followed a
decree of the Congregation of the Index dated 5 March 1616,
prohibiting various heretical works to which were added any
advocating the Copernican system. In this decree no mention is
made of Galileo, or of any of his works. Neither is the name of
the pope introduced, though there is no doubt that he fully
approved the decision, having presided at the session of the
Inquisition, wherein the matter was discussed and decided. In thus
acting, it is undeniable that the ecclesiastical authorities
committed a grave and deplorable error, and sanctioned an
altogether false principle as to the proper use of Scripture.
Galileo and Foscarini rightly urged that the Bible is intended to
teach men to go to heaven, not how the heavens go. At the same
time, it must not be forgotten that, while there was as yet no
sufficient proof of the Copernican system, no objection was made
to its being taught as an hypothesis which explained all phenomena
in a simpler manner than the Ptolemaic, and might for all
practical purposes be adopted by astronomers. What was objected to
was the assertion that Copernicanism was in fact true, "which
appears to contradict Scripture". It is clear, moreover, that the
authors of the judgment themselves did not consider it to be
absolutely final and irreversible, for Cardinal Bellarmine, the
most influential member Of the Sacred College, writing to
Foscarini, after urging that he and Galileo should be content to
show that their system explains all celestial phenomena -- an
unexceptional proposition, and one sufficient for all practical
purposes -- but should not categorically assert what seemed to
contradict the Bible, thus continued:
I say that if a real proof be found that the sun is fixed and does
not revolve round the earth, but the earth round the sun, then it
will be necessary, very carefully, to proceed to the explanation
of the passages of Scripture which appear to be contrary, and we
should rather say that we have misunderstood these than pronounce
that to be false which is demonstrated.
By this decree the work of Copernicus was for the first time
prohibited, as well as the "Epitome" of Kepler, but in each
instance only donec corrigatur, the corrections prescribed being
such as were necessary to exhibit the Copernican system as an
hypothesis, not as an established fact. We learn further that with
permission these works might be read in their entirety, by "the
learned and skilful in the science" (Remus to Kepler). Galileo
seems, says von Gebler, to have treated the decree of the
Inquisition pretty coolly, speaking with satisfaction of the
trifling changes prescribed in the work of Copernicus. He left
Rome, however, with the evident intention of violating the promise
extracted from him, and, while he pursued unmolested his searches
in other branches of science, he lost no opportunity of
manifesting his contempt for the astronomical system which he had
promised to embrace. Nevertheless, when in 1624 he again visited
Rome, he met with what is rightly described as "a noble and
generous reception". The pope now reigning, Urban VIII, had, as
Cardinal Barberini, been his friend and had opposed his
condemnation in 1616. He conferred on his visitor a pension, to
which as a foreigner in Rome Galileo had no claim, and which, says
Brewster, must be regarded as an endowment of Science itself. But
to Galileo's disappointment Urban would not annul the former
judgment of the Inquisition. After his return to Florence, Galileo
set himself to compose the work which revived and aggravated all
former animosities, namely a dialogue in which a Ptolemist is
utterly routed and confounded by two Copernicans. This was
published in 1632, and, being plainly inconsistent with his former
promise, was taken by the Roman authorities as a direct challenge.
He was therefore again cited before the Inquisition, and again
failed to display the courage of his opinions, declaring that
since his former trial in 1616 he had never held the Copernican
theory. Such a declaration, naturally was not taken very
seriously, and in spite of it he was condemned as "vehemently
suspected of heresy" to incarceration at the pleasure of the
tribunal and to recite the Seven Penitential Psalms once a week
for three years.
Under the sentence of imprisonment Galileo remained till his death
in 1642. It is, however, untrue to speak of him as in any proper
sense a "prisoner". As his Protestant biographer, von Gebler,
tells us, "One glance at the truest historical source for the
famous trial, would convince any one that Galileo spent altogether
twenty-two days in the buildings of the Holy Office (i.e. the
Inquisition), and even then not in a prison cell with barred
windows, but in the handsome and commodious apartment of an
official of the Inquisition." For the rest, he was allowed to use
as his places of confinement the houses of friends, always
comfortable and usually luxurious. It. is wholly untrue that he
was -- as is constantly stated -- either tortured or blinded by
his persecutors -- though in 1637, five years before his death, he
became totally blind -- or that he was refused burial in
consecrated ground. On the contrary, although the pope (Urban
VIII) did not allow a monument to be erected over his tomb, he
sent his special blessing to the dying man, who was interred not
only in consecrated ground, but within the church of Santa Croce
at Florence. Finally, the famous "E pur si muove", supposed to
have been uttered by Galileo, as he rose from his knees after
renouncing the motion of the earth, is an acknowledged fiction, of
which no mention can be found till more than a century after his
death, which took place 8 January 1642, the year in which Newton
was born.
Such in brief is the history of this famous conflict between
ecclesiastical authority and science, to which special theological
importance has been attached in connection with the question of
papal infallibility. Can it be said that either Paul V or Urban
VIII so committed himself to the doctrine of geocentricism as to
impose it upon the Church as an article of faith, and so to teach
as pope what is now acknowledged to be untrue? That both these
pontiffs were convinced anti-Copernicans cannot be doubted, nor
that they believed the Copernican system to be unscriptural and
desired its suppression. The question is, however, whether either
of them condemned the doctrine ex cathedra. This, it is clear,
they never did. As to the decree of 1616, we have seen that it was
issued by the Congregation of the Index, which can raise no
difficulty in regard of infallibility, this tribunal being
absolutely incompetent to make a dogmatic decree. Nor is the case
altered by the fact that the pope approved the Congregation's
decision in forma communi, that is to say, to the extent needful
for the purpose intended, namely to prohibit the circulation of
writings which were judged harmful. The pope and his assessors may
have been wrong in such a judgment, but this does not alter the
character of the pronouncement, or convert it into a decree ex
cathedra.
As to the second trial in 1633, this was concerned not so much
with the doctrine as with the person of Galileo, and his manifest
breach of contract in not abstaining from the active propaganda of
Copernican doctrines. The sentence, passed upon him in
consequence, clearly implied a condemnation of Copernicanism, but
it made no formal decree on the subject, and did not receive the
pope's signature. Nor is this only an opinion of theologians; it
is corroborated by writers whom none will accuse of any bias in
favour of the papacy. Thus Professor Augustus De Morgan (Budget of
Paradoxes) declares
It is clear that the absurdity was the act of the Italian
Inquisition, for the private and personal pleasure of the pope --
who knew that the course he took could not convict him as pope --
and not of the body which calls itself the Church.
And von Gebler ("Galileo Galilei"):
The Church never condemned it (the Copernican system) at all, for
the Qualifiers of the Holy Office never mean the Church.
It may be added that Riceloll and other contemporaries of Galileo
were permitted, after 1616, to declare that no anti-Copernican
definition had issued from the supreme pontiff.
More vital at the present day is the question with which we
commenced: "Does not the condemnation of Galileo prove the
implacable opposition of the Church to scientific progress and
enlightenment?" It may be replied with Cardinal Newman that this
instance serves to prove the opposite, namely that the Church has
not interfered with physical science, for Galileo's case "is the
one stock argument" (Apologia 5). So too Professor De Morgan
acknowledges ("Motion of the Earth" in English Cyclopaedia):
The Papal power must upon the whole have been moderately used in
matters of philosophy, if we may judge by the great stress laid on
this one case of Galileo. It is the standing proof that an
authority which has lasted a thousand years was all the time
occupied in checking the progress of thought.
So Dr. Whewell speaking of this same case says (History of the
Inductive Sciences):
I would not be understood to assert the condemnation of new
doctrines to be a general or characteristic practice of the Romish
Church. Certainly the intelligent and cultivated minds of Italy,
and many of the most eminent of her ecclesiastics among them, have
been the foremost in promoting and welcoming the progress of
science, and there were found among the Italian ecclesiastics of
Galileo's time many of the earliest and most enlightened adherents
of the Copernican system.
JOHN GERARD
Transcribed by Carl H. Horst
From the Catholic Encyclopedia, copyright � 1913 by the
Encyclopedia Press, Inc. Electronic version copyright � 1996 by
New Advent, Inc.
Taken from the New Advent Web Page (www.knight.org/advent).
This article is part of the Catholic Encyclopedia Project, an
effort aimed at placing the entire Catholic Encyclopedia 1913
edition on the World Wide Web. The coordinator is Kevin Knight,
editor of the New Advent Catholic Website. If you would like to
contribute to this worthwhile project, you can contact him by e-
mail at (knight.org/advent). For more information please download
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