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Both John Draper and Andrew Dickson White used the Galileo Affair as one of their many examples of the religious oppression of scientific progress. However, lingering in the background to this affair is Copernicus and his monumental work, On the Revolutions of the Heavenly Spheres, which revived the heliocentric model of the universe that eventually earned Galileo’s favor. I will thus begin by analyzing Draper and White’s historical accounts of the publication and reception of Copernicus’ astronomical theory and what this means for Draper and White’s original conflict thesis.

Draper describes Copernicus as being aware that his doctrines were opposed to revealed truth and therefore putting them forward only suppositionally or hypothetically, as is stated in the introduction to the book. Draper seems to be unaware that Copernicus did not write the anonymous introduction to De Revolutionibus and that its message is inconsistent with his actual position. Draper thus presents Copernicus as an individual who was “full of misgivings” (Draper, 167-169). White, on the other hand, blames the actual author of the introduction, the Lutheran theologian Andreas Osiander, for forcing Copernicus’ great truth to appear before the world sneaking and crawling by “pretending that the book…suggested a hypothesis instead of announcing a truth” (White, 124).

Draper moves immediately from the publication of De Revolutionibus in 1543 to its condemnation by the Inquisition in 1616, without any explicit mention of the long span of time between these two events. The effect is that the condemnation appears like an immediate and inevitable reaction on the part of the Catholic Church. White acknowledges that in the intervening seventy-three years the Church and theologians were, while against it, largely quiet on the matter. However, he notes that Protestants, too, also rejected the doctrine. He points to Martin Luther, but also to the University of Wittenberg, where “the facts confirming the Copernican theory” were “carefully kept out of sight” (White, 128). Of the four most important members of the circle of astronomers at Wittenberg from 1530 to 1560, White identifies Melanchthon and Caspar Peucer as condemning the Copernican doctrine, with Rheticus and Reinhold believing the system to be true but prevented from teaching or disseminating the new ideas. As for Reinhold, White writes, “convinced of the truth of the new theory, he was obliged to advocate the old; if he mentioned the Copernican ideas, he was compelled to overlay then with the Ptolemaic” (White, 129).

Rheticus, to be sure, was indeed a total convert to the reality of the Copernican system of astronomy, but Reinhold did not seem to accept it in the way that White suggests, that is, as a physical description of reality. Reinhold’s own copy of De Revolutionibus is heavily annotated in the later, highly technical chapters, but hardly contains anything in the early cosmological ones in which Copernicus argued in favor of placing the sun at the center of the universe (Gingerich, The Book Nobody Read, 23-24). In fact, Reinhold had scribbled across the title page of the book what he admired most about Copernicus’s achievement and it had nothing to do with assigning any motion to the Earth: “The axiom of astronomy: Celestial motions are circular and uniform or composed of circular and uniform parts.” Ptolemy had introduced a device known as the equant to his geocentric cosmology which seemed to violate the elegant an ancient principle of uniform circular motion (only angular motion is uniform around an equant). Thus, Reinhold praised Copernicus for his elimination of the equant (by means of a series of epicyclets) and thereby restoring for astronomy that grand principle (Gingerich, 54-55). Such a mathematical device was not tied to Copernicanism, but could potentially be applied to the Ptolemaic system.

History does not always fit kindly into rigid dichotomies. White wants people in the 16^th century to either accept or reject Copernicanism in its strictest and fullest sense: as a physically true scientific theory of cosmology. Yet, the manner in which people of that time engaged with Copernicus’ work is far more complex, and this is none the more evident than in the Melanchthon circle at Wittenberg. Reinhold may have rejected the physical principles but he found it useful to use Copernican planetary mechanisms to produce his Prutenic Tables. Melanchthon himself praised Copernicus’ lunar theory and made use of Copernican data. Caspar Peucer did much to consolidate these pragmatic aspects of Copernicus’ system into the scientific curriculum at Wittenberg, contrary to the impression given by White. This demonstrates that, at least among Protestants at Wittenberg, some sort of pragmatic assimilation is a much more appropriate interpretive framework than conflict.

Draper is effectively able to portray the adversaries of Copernicus’ heliocentricism in an even more negative light by claiming Copernicus’ book to be much more than it actually is. This is apparent when he writes:

Astronomers justly affirm that the book of Copernicus, “De Revolutionibus,” changed the face of their science. It incontestably established the heliocentric theory. It showed that the distance of the fixed stars is infinitely great, and that the earth is a mere point in the heavens. Anticipating Newton, Copernicus imputed gravity to the sun, the moon, and heavenly bodies, but he was led astray by assuming that the celestial motions must be circular. (Draper, 168)

If Copernicus’ book had really “incontestably established the heliocentric theory” then one wonders why Galileo had struggled at all in his attempts to advance that theory! Of course, De Revolutionibus did not establish the truth of heliocentricism nor would we consider much of it correct today. Other than the fact that Copernicus assigns motion to the Earth and makes it a planet revolving around the sun, the rest of the book resembles the works of ancient and medieval astronomers (Kuhn, The Copernican Revolution, 135). Copernicus kept much of what he inherited from the Ptolemaic traditions, including epicycles and eccentrics, and, as the title of his work suggests, the celestial spheres that carried the planets around (on the revolution of the heavenly spheres or orbs). Draper indicates that Copernicus was “led astray by assuming that the celestial motions must be circular,” but preserving uniform and circular celestial motion was essential to his project. He did so by doing away with the equant which had contributed in turning Ptolemy’s system into, in Copernicus’ opinion, a “monster.” The uniform and circular motion of the planets was accepted in principle by all astronomers in his day and even later, by Galileo himself.

Draper also states that Copernicus showed that the distance from the solar system to the outer stars is “infinitely great.” Copernicus, however, did not demonstrate this to be true, rather, what he did carried significantly less force. One consequence of the Earth’s annual revolution around the sun is stellar parallax, where the apparent position of a star against the stellar backdrop shifts over the course of the year (Kuhn, 163). The closer the star is to the Earth, the more apparent this shift will be, the further, the less apparent. No stellar parallax, however, is visible with the naked eye (the only instrument of observation available to 16^th century astronomers), so Copernicus merely suggested that the distance between the fixed stars and the rest of the planetary system must be much further away than initially thought. This is not a proof, because the lack of any visible stellar parallax is also perfectly explainable under the hypothesis that the Earth does not move. Indeed, this remained a potent argument against the Earth’s motion for some time, and stellar parallax was not even seen with a telescope until 1838.

As for Copernicus’ supposedly anticipating Newton by imputing gravity to the rest of the heavenly bodies, Draper again exaggerates what Copernicus actually attempted to do. He certainly did not conceive of gravity as a force as Newton would, but rather, he conceived it entirely within an Aristotelian framework as a natural motion of bodies made of the elements Earth and Water. Only, he broke from Aristotle by attributing a natural circular motion to all Earthly objects as well to explain why they don’t fly off of the Earth as it rotates on its axis (Kuhn, 148-155). This was about as far as Aristotelianism could be stretched to accommodate a sun-centered solar system. Science would have to invent an entirely new physics before heliocentrism could be fully assimilated – a project that would not be completed until Newton’s Principia. Until then, there were numerous philosophical objections (not to mention religious ones) to the physical truth of the Copernican system.

We have now seen at least two ways in which the conflict thesis, in respect to Copernicus, has been unjustly advanced. By forcing the participants into strict dichotomies, such as pro and anti-Copernican, and by exaggerating the actual content of Copernicus’ book itself, conflict is created. This is not to say that there was no conflict, only that the nature of that conflict is far more complex and nuanced. One could accept the hypothesis as a supposition that deserves careful consideration, as Andreas Osiander did, or one could accept the mathematical models that Copernicus produced while rejecting or simply not considering whether the Earth actually moves, as the Wittenberg circle did. Or, one could even accept some physical aspects of Copernicus’ theory and reject others, as did Nicolai Reymers Baer and Tycho Brahe, who each accepted the axial rotation of the Earth but rejected any orbital revolution (Brooke, Science and Religion, 90-91).

In the next part I will move on to Galileo and his famous telescope.