to abandon the medieval hope of doctrinal unity, and this increased men's freedom to think for
themselves, even about fundamentals. The diversity of creeds in different countries made it
possible to escape persecution by living abroad. Disgust with theological warfare turned the
attention of able men increasingly to secular learning, especially mathematics and science. These
are among the reasons for the fact that, while the sixteenth century, after the rise of Luther, is
philosophically barren, the seventeenth contains the greatest names and marks the most notable
advance since Greek times. This advance began in science, with which I shall deal in my next
chapter.
CHAPTER VI The Rise of ScienceALMOST everything that distinguishes the modern world from earlier centuries is attributable to
science, which achieved its most spectacular triumphs in the seventeenth century. The Italian
Renaissance, though not medieval, is not modern; it is more akin to the best age of Greece. The
sixteenth century, with its absorption in theology, is more medieval than the world of Machiavelli.
The modern world, so far as mental outlook is concerned, begins in the seventeenth century. No
Italian of the Renaissance would have been unintelligible to Plato or Aristotle; Luther would have
horrified Thomas Aquinas, but would not have been difficult for him to understand. With the
seventeenth century it is different: Plato and Aristotle, Aquinas and Occam, could not have made
head or tail of Newton.
The new conceptions that science introduced profoundly influenced modern philosophy.
Descartes, who was in a sense the founder of modern philosophy, was himself one of the creators
of seventeenthcentury science. Something must be said about the methods and results of
astronomy and physics before the mental atmosphere of the time in which modern philosophy
began can be understood.
Four great men-- Copernicus, Kepler, Galileo, and Newton--are