FREE ESSAY ON GALILEO GALILEI

GALILEO GALILEI

Galileo Galilei
From an early age Galileo Galilei manifested his aptitude for mathematical and mechanical
pursuits, but his parents, wishing to turn him aside from studies that 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 among the most renowned natural philosophers. Galileo's great
achievements are magnified by the fact that, happily combining experiment with
calculation, he opposed the prevailing system. This system did not encourage going
directly to nature for investigation of her laws and processes, instead it was held that
these were best learned from authorities, especially that of Aristotle who was supposed
to have spoken the last word upon all such matters. Against such a superstition Galileo
resolutely and vehemently set himself. He not only soon discredited many beliefs that had
been accepted as indisputable, but aroused a storm of opposition and indignation amongst
those whose opinions he discredited. Galileo 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. 
Galileo is most widely remembered for his astronomical discoveries. 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. Since these were 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.
Upon obtaining this proof, Galileo, profoundly assured of the truth of his cause, set
himself with his habitual vehemence to convince others, and so helped to create the
troubles that greatly embittered the latter part of his life. At first, on Galileo's
arrival in 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.
However, four years later the ecclesiastical authorities took alarm at the persistence
with which Galileo proclaimed the truth of the Copernican doctrine. They were firmly
convinced, with Bacon and others, that the new teaching was radically false and
unscientific. 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. 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. The
pope fully approved the decision, since he had 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
rightly urged that the Bible is intended to teach men to go to heaven, not how the
heavens go. He left Rome 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 described as a noble and generous reception. The pope now reigning, Urban VIII, had,
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 that 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. At the end of his trial, as Galileo rose from his knees after renouncing
the motion of the earth he said, E pur si muove. (It does move.) This last assertion of
this great astronomer serves as fitting epigraph of his discovery-filled life, and of the
struggle for truth and science that pervaded the second half of his life.
Bibliography
Cobb, Vicki. Truth or Trial: The Story of Galileo Galilei. New York: Coward, McCann, and
Geoghegan, 1979.
MacLachlan, James. Galileo Galilei: First Physicist. New York: Oxford University Press,
1997.
Sharatt, Michael. Galileo: Decisive Innovator. Cambridge: Cambridge University Press,
1990.