The reception of the new work was also surprisingly mild, at first, in Catholic circles. As early as 1533 Albert Widmanstetter had told Clement VII of the Copernican hypothesis and the pope did not, at least, condemn it. Moreover it was a cardinal, Schönberg, who consulted Paul III on the matter [Sidenote: 1536] and then urged Copernicus to publish his book, though in his letter the language is so cautiously guarded against possible heresy that not a word is said about the earth moving around the sun but only about the moon and the bodies near it so doing. [Sidenote: 1579] A Spanish theologian, Didacus a Stunica (Zuñiga) wrote a commentary on Job, which was licensed by the censors, accepting the Copernican astronomy.
But gradually, as the implications of the doctrine became apparent, the church in self-defence took a strong stand against it. [Sidenote: March 5, 1616] The Congregation of the Index issued a decree saying, "Lest opinions of this sort creep in to the destruction of Catholic truth, the book of Nicholas Copernicus and others [defending his hypothesis] are suspended until they be corrected." A little later Galileo was forced, under the threat of torture, to recant this heresy. Only when the system had become universally accepted, did the church, in 1822, first expressly permit the faithful to hold it.
The philosophers were as shy of the new light as {623} the theologians. Bodin in France and Bacon in England both rejected it; the former was conservative at heart and the latter was never able to see good in other men's work, whether that of Aristotle or of Gilbert or of the great Pole. Possibly he was also misled by Osiander's preface and by Tycho Brahe. Giordano Bruno, however, welcomed the new idea with enthusiasm, saying that Copernicus taught more in two chapters than did Aristotle and the Peripatetics in all their works.
Astronomers alone were capable of weighing the evidence scientifically and they, at first, were also divided. Erasmus Reinhold, of Wittenberg, accepted it and made his calculations on the assumption of its truth, as did an Englishman, John Field. [Sidenote: 1556] Tycho Brahe, [Sidenote: Tycho Brahe, 1546-1601] on the other hand, tried to find a compromise between the Copernican and Ptolemaic systems. He argued that the earth could not revolve on its axis as the centrifugal force would hurl it to pieces, and that it could not revolve around the sun as in that case a change in the position of the fixed stars would be observed. Both objections were well taken, of course, considered in themselves alone, but both could be answered by a deeper knowledge. Brahe therefore considered the earth as the center of the orbits of the moon, sun, and stars, and the sun as the center of the orbits of the planets.
The attention to astronomy had two practical corollaries, the improvement of navigation and the reform of the calendar. Several better forms of astrolabe, of "sun-compass" (or dial turnable by a magnet) and an "astronomical ring" for getting the latitude and longitude by observation of sun and star, were introduced.
[Sidenote: Reform of calendar]
The reform of the Julian calendar was needed on account of the imperfect reckoning of the length of the {624} year as exactly 365 1/4 days; thus every four centuries there would be three days too much. It was proposed to remedy this for the present by leaving out ten days, and for the future by omitting leap-year every century not divisible by 400. The bull of Gregory XIII, [Sidenote: February 24, 1582] who resumed the duties of the ancient Pontifex Maximus in regulating time, enjoined Catholic lands to rectify their calendar by allowing the fifteenth of October, 1582, to follow immediately after the fourth. This was done by most of Italy, by Spain, Portugal, Poland, most of Germany, and the Netherlands. Other lands adopted the new calendar later, England not until 1752 and Russia not until 1917.
[1] I.e. the principle thus formulated in the Encyclopaedia Britannica, s.v. "Mathematics": "If s is any class and zero a member of it, also if when x is a cardinal number and a member of s, also x + 1 is a member of s, then the whole class of cardinal numbers is contained in s."
[2] Eratosthenes (276-196 B.C.) had correctly calculated the earth's circumference at 25,000, which Poseidonius (c. 135-50 B.C.) reduced to 18,000, in which he was followed by Ptolemy (2d century A.D.).