Page:Collected Works of Dugald Stewart Volume 1.djvu/55

Rh seems, all at once, to have awakened with renovated and giant strength from his long sleep. In less than a century from the invention of printing and the fall of the Eastern empire, Copernicus discovered the true theory of the planetary motions, and a very few years afterwards, was succeeded by the three great precursors of Newton—Tycho Brahe, Kepler, and Galileo. The step made by Copernicus may be justly regarded as one of the proudest triumphs of human reason;—whether we consider the sagacity which enabled the author to obviate, to his own satisfaction, the many plausible objections which must have presented themselves against his conclusions, at a period the theory of motion was so imperfectly understood; or the bold spirit of inquiry which encouraged him to exercise his private judgment, in opposition to the authority of Aristotle,—to the decrees of the Church of Rome,—and to the universal belief of the learned, during a long succession of ages. He appears, indeed, to have well merited the encomium bestowed on him by Kepler, when he calls him "a man of vast genius, and, what is of still greater moment in these researches, a man of a free mind." The establishment of the Copernican system, beside the new field of study which it opened to Astronomers, must have had great effects on philosophy in all its branches, by inspiring those sanguine prospects of future improvement, which stimulate curiosity and invigorate the inventive powers. It afforded to the common sense, even of the illiterate, a palpable and incontrovertible proof, that the ancients had not exhausted the stock of possible discoveries; and that, in matters of science, the creed of the Romish Church was not infallible. In the conclusion of one of Kepler's works, we perceive the influence of these prospects on his mind. "Hæc et cetera hujusmodi latent in pandectis ævi sequentis, non antea discenda, quam librum hunc Deus arbiter seculorum recluserit mortalibus."