History of the Intellectual Development of Europe, Volume II (of 2) / Revised Edition

by John William Draper

Galileo constructs one.It is needless to enter on any examination of the authorship of this invention. It is enough for our purpose to know that Lippershey, a Dutchman, had made one toward the close of 1608, and that Galileo, hearing of the circumstance, but without knowing the particulars of the construction, in April or May of the following year invented a form of it for himself. Not content with admiring how close and large it made terrestrial objects, he employed it for examining the heavens. Telescopic astronomical discoveries. On turning it to the moon, he found that she has mountains casting shadows, and valleys like those of the earth. The discovery of innumerable fixed stars—not fewer than forty were counted by him in the well-known group of the Pleiades—up to that time unseen by man, was felt at once to offer an insuperable argument against the opinion that these bodies were created only to illuminate the night; indeed, it may be said that this was a death-blow to the time-honoured doctrine of the human destiny of the universe. Already Galileo began to encounter vulgar indignation, which accused him loudly of impiety. On January 7th, 1610, he discovered three of Jupiter's satellites, and a few days later the fourth. To these he gave the designation of the Medicean stars, and in his "Sidereal Messenger" published an account of the facts he had thus far observed. As it was perceived at once that this planet offered a miniature representation of the ideas of Copernicus respecting the solar system, this discovery was received by the astronomical party with the liveliest pleasure, by the ecclesiastical with the most bitter opposition, some declaring that it was a mere optical deception, some a purposed fraud, some that it was sheer blasphemy, and some, fairly carrying out to its consequences the absurd philosophy of the day, asserted that, since [262] the pretended satellites were invisible to the naked eye, they must be useless, and, being useless, they could not exist. Continuing his observations, Galileo found that Saturn differs in an extraordinary manner from other planets; but the telescope he used not being sufficient to demonstrate the ring, he fell into the mistake that the body of the planet is triple. This was soon followed by the discovery of the phases of Venus, which indisputably established for her a motion round the sun, and actually converted what had hitherto, on all hands, been regarded as one of the weightiest objections against the Copernican theory, into a most solid support. "If the doctrine of Copernicus be true, the planet Venus ought to show phases like the moon, which is not the case;" so said the objectors. Copernicus himself saw the difficulty, and tried to remove it by suggesting that the planet might be transparent. The telescope of Galileo for ever settled the question by showing that the expected phases do actually exist.

Commencing opposition to Galileo.In the garden of Cardinal Bandini at Rome, A.D. 1611, Galileo publicly exhibited the spots upon the sun. He had observed them the preceding year. Goaded on by the opposition his astronomical discoveries were bringing upon him, he addressed a letter in 1613 to the Abbe Castelli, for the purpose of showing that the Scriptures were not intended as a scientific authority. This was repeating Bruno's offence. Hereupon the Dominicans, taking alarm, commenced to attack him from their pulpits. It shows how reluctantly, and with what misgivings the higher ecclesiastics entered upon the quarrel, that Maraffi, the general of the Dominicans, apologized to Galileo for what had taken place. The astronomer now published another letter reiterating his former opinions, asserting that the Scriptures were only intended for our salvation, and otherwise defending himself, and recalling the fact that Copernicus had dedicated his book to Pope Paul III.

He is summoned to Rome. Through the suggestion of the Dominicans, Galileo was now summoned to Rome to account for his conduct and opinions before the Inquisition. He was accused of having taught that the earth moves; that the sun is stationary; and of having attempted [263] to reconcile these doctrines with the Scriptures. The sentence was that he must renounce these heretical opinions, and pledge himself that he would neither publish nor defend them for the future. Is condemned by the Inquisition, In the event of his refusal he was to be imprisoned. With the fate of Bruno in his recollection, he assented to the required recantation, and gave the promise demanded. The Inquisition then proceeded to deal with the Copernican system, condemning it as heretical; the letters of Galileo, which had given rise to the trouble, were prohibited; also Kepler's epitome of the Copernican theory, and also the work of Copernicus. which condemns the Copernican system. In their decree prohibiting this work "De Revolutionibus," the Congregation of the Index, March 5, 1616, denounced the new system of the universe as "that false Pythagorean doctrine utterly contrary to the Holy Scriptures."

Again it appears how reluctant the Roman authorities were to interfere, and how they were impelled rather by the necessity of their position than by their personal belief in the course they had been obliged to take. The personal sentiments of the Popes. After all that had passed, the Pope, Paul V., admitted Galileo to an audience, at which he professed to him personally the kindest sentiments, and assured him of safety. When Urban VIII. succeeded to the pontifical chair, Galileo received the distinction of not less than six audiences; the Pope conferred on him several presents, and added the promise of a pension for his son. In a letter to the Duke of Florence his Holiness used the most liberal language, stated how dear to him Galileo was, that he had very lovingly embraced him, and requested the duke to show him every favour.

Galileo publishes "The System of the World."Whether it was that, under these auspicious circumstances, Galileo believed he could with impunity break through the engagement he had made, or whether an instinctive hatred of that intellectual despotism and hypocrisy which was weighing upon Europe became irrepressible in his breast, in 1632 he ventured on the publication of his work, entitled "The System of the World," its object being to establish the truth of the Copernican doctrine. It is [264] composed in the dialogue form, three speakers being introduced, two of them true philosophers, the third an objector. Whatever may have been the personal opinion of the Pope, there can be no doubt that his duty rendered it necessary for him to act. Galileo was therefore again summoned before the Inquisition, the Tuscan ambassador expostulating against the inhumanity of thus dealing with an old man in ill health. But no such considerations were listened to, and Galileo was compelled to appear at Rome, February, 1633, and surrender himself to the Holy Office. The Pope's nephew did all in his power to meet the necessity of the Church and yet to spare the dignity of science. He paid every attention to the personal comfort of the accused. When the time came for Galileo to be put into solitary confinement, he endeavoured to render the imprisonment as light as possible; but, finding it to prey upon the spirits of the aged philosopher, he, on his own responsibility, liberated him, permitting him to reside in the house of the Tuscan ambassador. Is again condemned by the Inquisition. The trial being completed, Galileo was directed to appear, on June 22nd, to hear his sentence. Clothed in the penitential garment, he received judgment. His heretical offences were specified, the pledges he had violated recited; he was declared to have brought upon himself strong suspicions of heresy, and to be liable to the penalties thereof; but from these he might be absolved if, with a sincere heart, he would abjure and curse his heresies. However, that his offences might not altogether go unpunished, and that he might be a warning to others, he was condemned to imprisonment during the pleasure of the Inquisition, his dialogues were prohibited by public edict, and for three years he was directed to recite, once a week, the seven penitential psalms.

His degradation and punishment.In his garment of disgrace the aged philosopher was now made to fall upon his knees before the assembled cardinals, and, with his hand on the Gospels, to make the required abjuration of the heliocentric doctrine, and to give the pledges demanded. He was then committed to the prison of the Inquisition; the persons who had been concerned in the printing of his book were punished; and the sentence and abjuration [265] were formally promulgated, and ordered to be publicly read in the universities. In Florence, the adherents of Galileo were ordered to attend in the Church of Santa Croce to witness his disgrace. After a short imprisonment in the jail of the Inquisition, he was ordered to Arcetri, and confined in his own house. Here severe misfortunes awaited him; his favourite daughter died; he fell into a state of melancholy; an application that he might go to Florence for the sake of medical advice was refused. It became evident that there was an intention to treat him with inexorable severity. After five years of confinement, permission was reluctantly accorded to him to remove to Florence for his health; but still he was forbidden to leave his house, or receive his friends, or even to attend mass during Passion Week without a special order. The Grand-duke tried to abate this excessive severity, directing his ambassador at the court of Rome to plead the venerable age and ill health of the immortal convict, and that it was desirable to permit him to communicate certain scientific discoveries he had made to some other person, such as Father Castelli. Not even that was accorded unless the interview took place in the presence of an official of the Inquisition. Soon after Galileo was remanded to Arcetri. He spent the weary hours in composing his work on Local Motion, his friends causing it to be surreptitiously published in Holland. The calamities of his old age. His infirmities and misfortunes now increased. In 1637 he became totally blind. In a letter he plaintively says, referring to this calamity, "So it pleases God, it shall therefore please me also." The exquisite refinement of ecclesiastical vengeance pursued him remorselessly, and now gave him permission to see his friends when sight was no longer possible. It was at this period that an illustrious stranger, the author of "Paradise Lost," visited him. Shortly after he became totally deaf; but to the last he occupied himself with investigations respecting the force of percussion. His death; is refused burial. He died, January, 1642, in the seventy-eighth year of his age, the prisoner of the Inquisition. True to its instincts, that infernal institution followed him beyond the grave, disputing his right to make a will, and denying him burial in [266] consecrated ground. The pope also prohibited his friends from raising to him a monument in the church of Santa Croce, in Florence. It was reserved for the nineteenth century to erect a suitable memorial in his honour.

Steady advance of the Copernican system.The result of the discoveries of Copernicus and Galileo was thus to bring the earth to her real position of subordination and to give sublimer views of the universe. Mœstlin expresses correctly the state of the case when he says, "What is the earth and the ambient air with respect to the immensity of space? It is a point, a punctule, or something, if there be any thing, less." It had been brought down to the condition of one of the members of a family—the solar system. And since it could be no longer regarded as holding all other bodies in submissive attendance upon it, dominating over their movements, there was reason to suppose that it would be found to maintain interconnexions with them in the attitude of an equal or subordinate; in other words, that general relations would be discovered expressive of the manner in which all the planetary members of the solar system sustain their movements round the sun.

Kepler, his mode of inquiry.Among those whose minds were thoroughly occupied with this idea, Kepler stands pre-eminently conspicuous. It is not at all surprising, considering the tone of thought of those times, that he regarded his subject with a certain mysticism. They who condemn his manner of thus viewing things do not duly appreciate the mental condition of the generation in which he lived. Whatever may be said on that point, no one can deny him a marvellous patience, and almost superhuman painstaking disposition. Guess after guess, hypothesis after hypothesis, he submitted to computations of infinite labour, and doubtless he speaks the melancholy truth when he says, "I considered and reflected till I was almost mad." Yet, in the midst of repeated disappointment, he held, with a truly philosophical determination, firmly to the belief that there must be some physical interconnexion among the parts of the solar system, and that it would certainly be displayed by the discovery of laws presiding over the distances, times, and velocities [267] of the planets. In these speculations he was immersed before the publications of Galileo. In his "Mysterium Cosmographicum" he says, "In the year 1595 I was brooding with the whole energy of my mind on the subject of the Copernican system."

Discovery of Kepler's laws.In 1609 he published his work entitled "On the Motion of Mars." This was the result of an attempt, upon which he had been engaged since the beginning of the century, to reconcile the motions of that planet to the hypothesis of eccentrics and epicycles. It ended in the abandonment of that hypothesis, and in the discovery of the two great laws now known as the first and second laws of Kepler. They are respectively that the orbits of the planets are elliptical, and that the areas described by a line drawn from the planet to the sun are proportional to the times.

In 1617 he was again rewarded by the discovery which passes under the designation of Kepler's third law: it expresses the relation of the mean distances of the planets from the sun with the times of their revolutions—"the squares of the periodic times are in the same proportion as the cubes of the distances." In his "Epitome of the Copernican Astronomy," published 1622, he showed that this law likewise holds good for the satellites of Jupiter as regards their primary.