IntroductionIn the creation of our modern world-view, few periods of Western history have been as decisive as the hundred fifty years that followed the publication, in 1543, of Copernicus’s sun-centered astronomy. During that period, what had been an earth-centered cosmos exploded into an infinite universe. The achievements in this age of genius have become legendary. In the physical sciences alone, there were momentous changes. When Kepler refined the Copernican system, he broke with centuries of tradition in suggesting that the planets moved in ellipses, not in circles. In his own colorful expression, he had laid a monstrous egg. Through his telescope Galileo observed more things in the heavens than had ever been dreamed of: moons of Jupiter and myriads of stars invisible to the naked eye. At a more technical level, the motion of bodies was subjected to mathematical analysis, concepts of inertia were formulated, and, as a fitting climax, Newton formulated his inverse-square law for gravity, which explained the planetary orbits. In the words of his contemporary Edmond Halley, he had penetrated the secret mansions of the gods.We continue to speak of a scientific revolution because earlier systems of belief were emphatically overthrown. In the philosophy of Aristotle, which had dominated the intellectual life of Europe since the thirteenth century, there had been a clear division in the cosmos between the perfect spheres beyond the moon and the corrupt sublunar sphere at the center of which stood the earth. By the end of the seventeenth century, in Newton’s science, the terms of reference had changed. There was now a universal law of gravitation. Because it applied to all bodies everywhere, the universe had at last become a universe. To divide it into two parts, heaven and earth, might still be admissible, as it was for Newton, when discussing theological and political symbolism. But the closed, partitioned, and spherical cosmos had had its day.