Although he
had no desire to raise the
theological issue, it must be
admitted that, the discussion once set on foot, he threw
himself into it with characteristic impetuosity, and thus
helped to precipitate a decision which it was his interest to
avert. In December 1613 a Benedictine
monk named Benedetto
Castelli, at that time professor of mathematics at the
University of Pisa, wrote to inform Galileo of a recent
discussion at the grandducal table, in which he had been
called upon to defend the Copernican doctrine against
theological objections. This task Castelli, who was a steady
friend and disciple of the Tuscan astronomer, seems to have
discharged with moderation and success. Galileo’s answer,
written, as he said himself, currenle calamo, was an
exposition of a formal theory as to the relations of physical
science to Holy Writ, still further developed in an elaborate
apology addressed by him in the following year (1614) to
Christina of Lorraine, dowager grand-duchess of Tuscany. Not
satisfied with explaining adverse texts, he met his opponents
with unwise audacity on their own ground, and endeavored to
produce scriptural confirmation of a system which seemed to
the ignorant many an incredible paradox, and to the scientific
few a beautiful but daring innovation.
The rising
agitation on the subject, fomented for their own purposes by
the rabid Aristotelians of the schools, was heightened rather
than allayed by these manifestoes, and on the fourth Sunday of
the following Advent found a voice in the pulpit of Santa
Maria Novella. Padre Caccini’s denunciation of the new
astronomy was indeed disavowed and strongly condemned by his
superiors; nevertheless, on the 5th of February 1615, another
Dominican monk named Lorini laid Galileo’s letter to
Casteili before the Inquisition.
Cardinal
Robert Bellarmin was at that time by far the most influential
member of the Sacred College. He was a man of vast learning
and upright piety, but, although personally friendly to
Galileo, there is no doubt that he saw in his scientific
teachings a danger to religion. The year 1615 seems to have
been a period of suspense. Galileo received, as the result of
a conference between Cardinals Bellarmin and Del Monte, a
semi-official warning to avoid theology, and limit himself to
physical reasoning. “Write freely-,” he was told by
Monsignor Dini, “but’ keep outside the sacristy.”
Unfortunately,
he had already committed himself to dangerous ground. In
December he repaired personally to Rome, full of confidence
that the weight of his arguments and the vivacity of his
eloquence could not fail to convert the entire pontifical
court to his views. He was cordially received, and eagerly
listened to, but his imprudent ardor served but to injure his
cause. On the 24th of February 1616 the consulting theologians
of the Holy Office characterized the two propositions: that
the sun is immovable in the center of the world, and that the
earth has a diurnal motion of rotation, the first as "absurd
in philosophy, and formally heretical, because expressly
contrary to Holy Scripture," and the second as "open
to the same censure in philosophy, and at least erroneous as
to faith."
Two days
later Galileo was, by command of the pope (Paul V.), summoned
to the palace of Cardinal Bellarmin, and there officially
admonished not thenceforward to "hold, teach or defend"
the condemned doctrine. This injunction he promised to obey.
On the 5th of March the Congregation of the Index issued a
decree reiterating, with the omission of the word heretical,
the censure of the theologians, suspending, Usque
Corrigatur, the great work of Copernicus, De
revolutioni bus orbium coeleslium, and absolutely
prohibiting a treatise by a Carmelite monk named Foscarini,
which treated the same subject from a theological point of
view. At the same time it was given to be understood that the
new theory of the solar system might be held, and the trivial
verbal alterations introduced into the Polish astonomer’s
book in 1620, when the work of revision was completed by
Cardinal Gaetani, confirmed this interpretation. This edict,
it is essential to observe, the responsibility for which rests
with a disciplinary congregation in no sense representing the
church, was never confirmed by the pope, and was virtually
repealed in 1757 under Benedict XIV.
Galileo
returned to Florence three months later, not ill-pleased, as
his letters testify, with the result of his visit to Rome. He
brought with him, for the refutation of calumnious reports
circulated by his enemies, a written certificate from Cardinal
Bellarmin, to the effect that no abjuration had been required
of or penance imposed upon him. During a prolonged audience he
had received from the pope assurances of private esteem and
personal protection; and he trusted to his dialectical
ingenuity’ to find the means of presenting his scientific
convictions under the transparent veil of an hypothesis.
Although a sincere Catholic, he seems to have laid but little
stress on the secret admonition of the Holy Office, which his
sanguine temperament encouraged him gradually to dismiss from
his mind. He preserved no written memorandum of its terms, and
it was represented to him, according to his own deposition in
1633, solely by Cardinal Bellarmin’s certificate, in which,
for obvious reasons, it was glossed over rather than expressly
recorded.
For seven
years, nevertheless, during which he led a life of studious
retirement in the Villa Segni at Bellosguardo, near
Florence, he maintained an almost unbroken silence. At the end
of that time he appeared in public with his Saggiatore,
a polemical treatise written in reply to the Libra
astronomica of Padre Grassi (under the pseudonym of
Lotario Sarsi), the Jesuit astronomer of the Collegio Romano.
The subject in debate was the nature of comets,. the
conspicuous appearance of three of which bodies in the year
1618 furnished the occasion of the controversy. Galileo’s
views, although erroneous, since he held comets to be mere
atmospheric emanations reflecting sunlight after the
evanescent fashion of a halo or a rainbow, were expressed with
such triumphant vigor, and embellished with such telling
sarcasms, that his opponent did not venture upon a reply. The Saggiatore
was printed at Rome in October 1623 by the Academy of the
Lincei, of which Galileo was, a member, with a dedication to
the new pope, Urban VIII., and notwithstanding some passages
containing a covert defense of Copernican opinions, was
received ‘with acclamation by ecclesiastical, no less than
by scientific authorities.
Everything
seemed now to promise a close of unbroken, prosperity to
Galileo’s career. Maffeo Barberini, his warmest friend and
admirer in the Sacred College, was, by the election of the 8th
of August 1625 seated on the pontifical throne: and the
marked distinction with
which he was received on his visit of congratulation to Rome
in 1624 encouraged him to hope for the realization of his
utmost wishes. He received every mark of private favor. The
pope admitted him to six long audiences in the course of two
months, wrote an enthusiastic letter to the grand-duke
praising the great astronomer, not only for his distinguished
learning, but also for his exemplary piety, and granted a
pension to his son Vincenzio, which was afterwards transferred
to himself, and paid, with some irregularities, to the end of
his life.
But on the
subject of the decree of 1616, the revocation of which Galileo
had hoped to obtain through his personal influence, he found
him inexorable. Yet there seemed reason to expect that it
would at least be interpreted in a liberal spirit, and
Galileo’s friends encouraged his imprudent confidence by
eagerly retailing to him every papal utterance which it was
possible to construe in a favorable sense. To Cardinal
Hohenzollern, Urban was reported to have said that the theory
of the earth’s motion had not been and could not be
condemned as heretical, but only as rash; and in 1630 the
brilliant Dominican monk Tommaso Campanella wrote to Galileo
that the pope had expressed to him in conversation his
disapproval of the prohibitory decree. Thus, in the full
anticipation of added renown, and without any misgiving as to
ulterior consequences, Galileo set himself, on his return to
Florence, to complete his famous but ill-starred work, the Dialogo
dei due massimi sistemi del mondo. Finished in. 1630, it
was not until January 1632 that it emerged from the presses of
Laodini at Florence. The book was originally intended to
appear in Rome, but unexpected obstacles interposed. The
Lincean Academy collapsed with the death of Prince Federigo
Cesi, its founder and president; an outbreak of plague impeded
communication between the various Italian cities; and the
imprimatur was finally extorted, rather than accorded, under
the pressure of private friendship and powerful
interest.
A tumult of
applause from every part of Europe followed its publication;
and it would be difficult to find in any language a book in
which animation and elegance of style are so happily combined
with strength and clearness of scientific exposition. Three
interlocutors, named respectively Salviati, Sagredo, and
Simplicio, take part in the four dialogues of which the work
is composed. The first-named expounds the views of the author;
the second is an eager and intelligent listener; the third
represents a well-meaning but obtuse Peripatetic, whom the
others treat at times with undisguised contempt. Salviati and
Sagredo took their names from two of Galileo’s early
friends, the former a learned Florentine, the latter a
distinguished Venetian gentleman; Simplicio ostensibly derived
his from the Sicilian commentator of Aristotle, but the choice
was doubtless instigated by a sarcastic regard to the double
meaning of the word. There were not wanting those who
insinuated that Galileo intended to depict the pope himself in
the guise of the simpleton of the party; and the charge,
though preposterous in itself, was supported by certain imprudence
of expression, which Urban was not permitted to ignore.
It was at
once evident that the whole tenor of this remarkable work was
in flagrant contradiction with the edict passed sixteen years
before its publication, as well as with the author’s
personal pledge of conformity to it. The ironical submission
with which it opened, and the assumed indetermination with
which it closed, were hardly intended to mask the vigorous
assertion of Copernican principles which formed its substance.
It is a singular circumstance, however, that the argument upon
which Galileo mainly relied as furnishing a physical
demonstration of the truth of the new theory rested on a
misconception. The ebb and flow of the tides were, he
asserted, a visible proof of the terrestrial double movement,
since they resulted from inequalities in the absolute
velocities through space of the various parts of the earth’s
surface, due to its rotation. To this notion, which took its
rise in a confusion of thought, he attached capital
importance, and he treated with scorn Kepler’s suggestion
that a certain occult attraction of the moon was in some way
concerned in the phenomenon. The theological censures which
the book did not fail to incur were not slow in making
themselves felt.
Towards
the end of August the
sale was prohibited; on the 1st of October the author was
cited to Rome by the Inquisition. He pleaded his, age, now
close upon seventy years, his infirm health, and the obstacles
to travel caused by quarantine regulations; but the pope was
sternly indignant at what he held to be his ingratitude and
insubordination, and no excuse was admitted. At length, on the
13th of February 1633, he arrived at the residence of
Niccolini, the Tuscan ambassador to the pontifical court, and
there abode in retirement for two months. From the 12th to the
30th of April he was detained in the palace of the
Inquisition, where he occupied the best apartments and was
treated with unexampled indulgence. On the 30th he was
restored to the hospitality of Niccolini, his warm partisan.
The accusation against him was that he had written in
contravention of the decree of 1616, and in defiance of the
command of the Holy Office communicated to him by Cardinal
Bellarmin; and his defense consisted mainly in a disavowal of
his opinions, and an appeal to his good intentions.
On the 21st
of June he was finally examined under menace of torture; but
he continued to maintain his assertion that after its
condemnation by the Congregation of the Index, he had never
held the Copernican theory. Since the publication of the
documents relating to this memorable trial, there can no
longer be any doubt, not only that the threat of torture was
not carried into execution, but that it was never intended
that it should be. On the 22nd of June, in the church of Santa
Maria sopra Minerva, Galileo read his recantation, and
received his sentence. He was condemned, as “ vehemently
suspected of heresy,” to incarceration at the pleasure of
the tribunal, and by way of penance was enjoined to recite
once a week for three years the seven penitential psalms. This
sentence was signed by seven cardinals, but did not receive
the customary papal ratification. The legend according to
which Galileo, rising from his knees after repeating the
formula of abjuration, stamped on the ground, and exclaimed, Eppur
si muove! is, as may readily be supposed, entirely
apocryphal.
Galileo
remained in the custody of the Inquisition from the 21st to
the 24th of June, on which day he was relegated to the Trinita
de Monti. Thence, on the 6th of July, he was permitted to
depart for Siena, where he spent several months in the house
of the archbishop, Ascanio Piccolomini, one of his numerous
and trusty friends. It was not until December that his earnest
desire of returning to Florence was realized, and the
remaining eight years of his life were spent in his villa at
Arcetri in the strict seclusion which was the prescribed
condition of his comparative freedom. Domestic afflictions
combined with numerous and painful infirmities to embitter his
old age. His sister-in-law and her whole family, who came to
live with him on his return from Rome, perished shortly
afterwards of the plague; and on the 2nd of April 1634 died,
to the inexpressible grief of her father, his eldest and best beloved
daughter, a nun in the convent of San Matteo at Arcetri.
Galileo was never married; but by a Venetian woman named
Itlarina Gamba he had three children: a son who married and
left descendants, and two daughters who took the veil at an
early age.
His
prodigious mental activity continued undiminished to the last.
In 1636 he completed his Dialog delle nisove scienze,
in which he recapitulated the results of his early experiments
and mature meditations on the principles of mechanics. This in
many respects his most valuable work was printed by the
Elzevirs at Leiden in 1638, and excited admiration equally
universal and more lasting than that accorded to his
astronomical treatises. His last telescopic discovery, that of
the moon’s diurnal and monthly librations, was made in 1637,
only a few months before his eyes were for ever closed in
hopeless blindness. It was in this condition that Milton found
him when he visited him at Arcetri in 1638. But the fire of
his genius was not even yet extinct. He continued his
scientific correspondence with unbroken interest and
undiminished logical acumen; he thought out the application of
the pendulum to the regulation of clockwork, which Huygens
successfully realized fifteen years later; and
he was engaged in dictating to his disciples, Viviani and
Torricelli, his latest ideas on the theory of impact when he
was seized with the slow fever which in two months brought him
to the grave.
On the 8th
of January 1642 he closed his long life of triumph and
humiliation, which just spanned the interval between the death
of Michelangelo and the birth of Isaac Newton. The
direct services which Galileo rendered to astronomy are
virtually summed up in his telescopic discoveries. To the
theoretical perfection of the science he contributed little or
nothing. He pointed out indeed that the so-called “third
motion,” introduced by Copernicus to account for the
constant parallelism of the earth’s axis, was a superfluous
complication. But he substituted the equally unnecessary
hypothesis of a magnetic attraction, and failed to perceive
that the phenomenon to be explained was, in relation to
absolute space, not a movement but the absence of movement.
The circumstance, however, which most seriously detracts from
his scientific reputation is his neglect of the discoveries
made during his lifetime by the greatest of his
contemporaries.
Kepler’s
first and second laws were published in 1609, and his third
ten years later. By these momentous inductions the geometrical
theory of the solar system was perfected, and a hitherto
unimagined symmetry was perceived to regulate the mutual
relations of its members. But by Galileo they were passed over
in silence. In his Dialogo del massimi sistemi, printed
not less than thirteen years after the last of the three laws
had been given to the world, the epicycles by which
Copernicus, adhering to the ancient postulate of uniform
circular motion, had endeavored to reduce to theory the
irregularities of the planetary movements, were neither
expressly adopted nor expressly rejected; and the conclusion
seems inevitable that this grave defection from the cause of
progress was due to his perhaps unconscious reluctance to
accept discoveries which he had not originated.
He still deserves credit for his innumerable observations,
which are some of the greatest foundations for the science of
astronomy.