Page:The Gradual Acceptance of the Copernican Theory of the Universe.djvu/103



STRONOMICAL thought on the Continent was more hampered, in the Catholic countries especially, by the restrictive opinions of the Church. Yet in 1757, when the decree prohibiting all books dealing with the Copernican doctrine was removed from the Index, that system had already long been adopted by the more celebrated academies of Europe, for so Mme. de Premontval claimed in 1750; and it was then reaching out to non-scientific readers, through simple accounts for "ladies and others not well versed in these somewhat technical matters." The great landmark in the development of the doctrine was the publication of Newton's Principia in 1687, though its effect in Europe was of course slower in being felt than it was in England. Newton's work and that of the astronomers immediately following him was influential except where the Church's prohibitions still held sway.

During this period, the books published in free Holland were more outspoken in their radical acceptance or in their uncertainty of the truth than were those published in the Catholic countries. Christian Huygens's treatises on the plurality of worlds not only fully accepted the Copernican doctrine, but like those of Bishop Wilkins in England, deduced therefrom the probability that the other planets are inhabited even as the earth is. A writer on the sphere in 1697 stated the different theories of the universe so that his readers might choose the one that to them appeared the most probable. He himself preferred the Cartesian explanation as the simplest and most convenient of all, "though it should be held merely as an hypothesis and not as in absolute agreement with the truth." Pierre Bayle also explained the different systems, but appears himself

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