The gradual acceptance of the Copernican theory of the universe Part 5

Johann Kepler[159] earned for himself the proud t.i.tle of "lawmaker for the universe" in defiance of his handicaps of ill-health, family troubles, and straitened finances.[160] Born in Weil, Wurtemberg, (December 27, 1571) of n.o.ble but indigent parents, he was a sickly child unable for years to attend school regularly. He finally left the monastery school in Mulifontane in 1586 and entered the university at Tubingen to stay for four and a half years. There he studied philosophy, mathematics, and theology (he was a Lutheran) receiving the degree of Master of Arts in 1591. While at the university he studied under Maestlin, professor of mathematics and astronomy, and a believer in the Copernican theory. Because of Maestlin's teaching Kepler developed into a confirmed and enthusiastic adherent to the new doctrine.

[Footnote 159: The authoritative biography is the _Vita_ by Frisch in vol. VIII, pp. 668-1028 of _Op. Om. Kep._]

[Footnote 160: Frisch: VIII, 718. [Transcriber's Note: Missing footnote reference in original text has been added above in a logical place.]]

In 1594 he reluctantly abandoned his favorite study, philosophy, and accepted a professorship in mathematics at Graetz in Styria. Two years later he published his first work: _Prodromus Dissertationum continens mysterium cosmographic.u.m_ etc. (1596) in which he sought to prove that the Creator in arranging the universe had thought of the five regular bodies which can be inscribed in a sphere according to which He had regulated the order, the number and the proportions of the heavens and their movements.[161] The book is important not only because of its novelty, but because it gave the Copernican doctrine public explanation and defense.[162] Kepler himself valued it enough to reprint it with his _Harmonia Mundi_ twenty-five years later. And it won for him appreciative letters from various scientists, notably from Tycho Brahe and Galileo.[163]

[Footnote 161: Delambre: _Astr. Mod._ 314-315.]

[Footnote 162: Frisch: VIII, 999.]

[Footnote 163: Ibid: VIII, 696.]

As Kepler, a Lutheran, was having difficulties in Graetz, a Catholic city, he finally accepted Tycho's urgent invitation to come to Prague.[164] He came early in 1600, and after some adjustments had been made between the two,[165] he and his family settled with Tycho that autumn to remain till the latter's death the following November.

Kepler himself then held the office of imperial mathematician by appointment for many years thereafter.[166]

[Footnote 164: Ibid: VIII, 699-715.]

[Footnote 165: Dreyer: 290-309.]

[Footnote 166: Frisch: VIII, 715.]

With the researches of Tycho's lifetime placed at his disposal, Kepler worked out two of his three great planetary laws from Tycho's observations of the planet Mars. Yet, as M. Bertrand remarks,[167] it was well for Kepler that his material was not too accurate or its variations (due to the then unmeasured force of attraction) might have hindered him from proving his laws; and luckily for him the earth's...o...b..t is so nearly circular that in calculating the orbit of Mars to prove its elliptical form, he could base his work on the earth's...o...b..t as a circle without vitiating his results for Mars.[168] That a planet's...o...b..t is an ellipse and not the perfect circle was of course a triumph for the new science over the scholastics and Aristotelians.

But they had yet to learn what held the planets in their courses.

[Footnote 167: Bertrand: p. 870-1.]

[Footnote 168: The two laws first appeared in 1609 in his _Physica Coelestis tradita commentarius de motu stellae martis_. (Frisch: VIII, 964.) The third he enunciated in his _Harmonia Mundi_, 1619.

(Ibid: VIII, 1013-1017.)]

From Kepler's student days under Maestlin when as the subject of his disputation he upheld the Copernican theory, to his death in 1630, he was a staunch supporter of the new teaching.[169] In his _Epitome Astronomiae Copernicanae_ (1616) he answered objections to it at length.[170] He took infinite pains to convert his friends to the new system. It was in vain that Tycho on his deathbed had urged Kepler to carry on their work not on the Copernican but on the Tychonic scheme.[171]

[Footnote 169: "Cor et animam meam": Kepler's expression in regard to the Copernician theory. Ibid: VIII, 957.]

[Footnote 170: Ibid: VIII, 838.]

[Footnote 171: Ibid: VIII, 742.]

Kepler had reasoned out according to physics the laws by which the planets moved.[172] In Italy at this same time Galileo with his optic tube (invented 1609) was demonstrating that Venus had phases even as Copernicus had declared, that Jupiter had satellites, and that the moon was scarred and roughened--ocular proof that the old system with its heavenly perfection in number (7 planets) and in appearance must be cast aside. Within a year after Galileo's death Newton was born[173] (January 4, 1643). His demonstration of the universal application of the law of gravitation (1687) was perhaps the climax in the development of the Copernican system. Complete and final proof was adding in the succeeding years by Roemer's (1644-1710) discovery of the velocity of light, by Bradley's (1693-1762) study of its aberration,[174] by Bessel's discovery of stellar parallax in 1838,[175] and by Foucault's experimental demonstration of the earth's axial motion with a pendulum in 1851.[176]

[Footnote 172: Kepler: _Op. Om._, I, 106: _Praefatio ad Lectorem_.]

[Footnote 173: Berry: 210.]

[Footnote 174: Berry: 265.]

[Footnote 175: Ibid: 359.]

[Footnote 176: Jacoby: 89.]

PART TWO

THE RECEPTION OF THE COPERNICAN THEORY.

CHAPTER I.

OPINIONS AND ARGUMENTS IN THE SIXTEENTH CENTURY.

During the lifetime of Copernicus, Roman Catholic churchmen had been interested in his work: Cardinal Schonberg wrote for full information, Widmanstadt reported on it to Pope Clement VII and Copernicus had dedicated his book to Pope Paul III.[177] But after his death, the Church authorities apparently paid little heed to his theory until some fifty years later when Giordano Bruno forced it upon their attention in his philosophical teachings. Osiander's preface had probably blinded their eyes to its implications.

[Footnote 177: See before, p. 30.]

The Protestant leaders were not quite so urbane in their att.i.tude.

While Copernicus was still alive, Luther is reported[178] to have referred to this "new astrologer" who sought to prove that the earth and not the firmament swung around, saying: "The fool will overturn the whole science of astronomy. But as the Holy Scriptures state, Joshua bade the sun stand still and not the earth." Melancthon was more interested in this new idea, perhaps because of the influence of Rheticus, his colleague in the University of Wittenberg and Copernicus's great friend and supporter; but he too preferred not to dissent from the accepted opinion of the ages.[179] Informally in a letter to a friend he implies the absurdity of the new teaching,[180]

and in his _Initia Doctrinae Physicae_ he goes to some pains to disprove the new a.s.sumption not merely by mathematics but by the Bible, though with a kind of apology to other physicists for quoting the Divine Witness.[181] He refers to the phrase in Psalm XIX likening the sun in its course "to a strong man about to run a race," proving that the sun moves. Another Psalm states that the earth was founded not to be moved for eternity, and a similar phrase occurs in the first chapter of Ecclesiastes. Then there was the miracle when Joshua bade the sun stand still. While this is a sufficient witness to the truths there are other proofs: First, in the turning of a circ.u.mference, the center remains motionless. Next, changes in the length of the day and of the seasons would ensue, were the position of the earth in the universe not central, and it would not be equidistant from the two poles. (He has previously disposed of infinity by stating that the heavens revolve around the pole, which could not happen if a line drawn from the center of the universe were infinitely projected).[182]

Furthermore, the earth must be at the center for its shadow to fall upon the moon in an eclipse. He refers next to the Aristotelian statement that to a simple body belongs one motion: the earth is a simple body; therefore it can have but one motion. What is true of the parts applies to the whole; all the parts of the earth are borne toward the earth and there rest; therefore the whole earth is at rest.

Quiet is essential to growth. Lastly, if the earth moved as fast as it must if it moves at all, everything would fly to pieces.[183]

[Footnote 178: Luther: _Tischreden_, IV, 575; "Der Narr will die ganze Kunst Astronomiae umkehren. Aber wie die heilige Schrift anzeigt, so heiss Josua die Sonne still stehen, und nicht das Erdreich."]

[Footnote 179: "Non est autem hominis bene inst.i.tuti dissentire a consensu tot saeculorum." Praefatio Philippi Melanthonis, 1531, in Sacro-Busto: _Libellus de Sphaera_ (no date).]

[Footnote 180: "Vidi dialogum et fui dissua.s.sor editionis. Fabula per sese paulatim consilescet; sed quidam putant esse egregiam _katorthoma_ rem tam absurdam ornare, sicut ille Sarmaticus Astronomis qui movet terram et figet solem. Profecto sapientes gubernatores deberent ingeniorum petulantia cohercere." _Epistola B. Mithobio_, 16 Oct. 1541. P. Melancthon: _Opera_: IV, 679.]

[Footnote 181: "Quamquam autem rident aliqui Physic.u.m testimonia divina citantem, tamen nos honestum esse censemus, Philosophiam conferre ad coelestia dicta, et in tanta caligine humanae mentis autoritatem divinam consulere ubicunque possumus." Melancthon: _Initia Doctrinae Physicae_: Bk. I, 63.]

[Footnote 182: Ibid: 60.]

[Footnote 183: Ibid: 59-67.]

Melancthon thus sums up the usual arguments from the Scriptures, from Aristotle, Ptolemy and the then current physics, in opposition to this theory. Not only did he publish his own textbook on physics, but he republished Sacrobosco's famous introduction to astronomy, writing for it a preface urging diligent study of this little text endorsed by so many generations of scholars.

Calvin, the great teacher of the Protestant Revolt, apparently was little touched by this new intellectual current.[184] He did write a semi-popular tract[185] against the so called "judicial" astrology, then widely accepted, which he, like Luther, condemns as a foolish superst.i.tion, though he values "la vraie science d'astrologie" from which men understand not merely the order and place of the stars and planets, but the causes of things. In his _Commentaries_, he accepts the miracle of the sun's standing still at Joshua's command as proof of the faith Christ commended, so strong that it will remove mountains; and he makes reference only to the time-honored Ptolemaic theory in his discussion of Psalm XIX.[186]

[Footnote 184: Farrar: _Hist. of Interpretation_: Preface, xviii: "Who," asks Calvin, "will venture to place the authority of Copernicus above that of the Holy Spirit?"]

[Footnote 185: Calvin: _Oeuvres Francois_: _Traite ... contre l'Astrologie_, 110-112.]

[Footnote 186: Calvin: _Op. Om._ in _Corpus Reformatorum_: vol. 25, 499-500; vol. 59, 195-196.]

For the absolute authority of the Pope the Protestant leaders subst.i.tuted the absolute authority of the Bible. It is not strange, then, that they ignored or derided a theory as yet unsupported by proof and so difficult to harmonize with a literally accepted Bible.