Aristotle's Physics

The History of Western Philosophy
Bertrand Russell

Ch. XXIII - Aristotle's Physics

Aristotle's physics were important and unquestioned until the time of Galileo. Today they are necessary to understand the history of philosophy, even if they are insignificant considering modern science.

Aristotle described the nature of a thing as its end. (An acorn's nature is to grow into an oak).

Motion is the fulfillment of some potentiality in Aristotle.

All the ancient philosophers except for Plato believed time was uncreated. Aristotle, in spite of being such a bulwark in Christian theology for thousands of years, found himself abandoned in this notion by the subsequent Christians who followed him dogmatically.

Aristotle taught that everything beneath the moon (sublunary) was subject to growth and decay. Everything above the moon was ungenerated and indestructible.

He taught the earth was spherical and the center of the universe.

Everything in the sublunary sphere was composed of the four elements. The heavenly bodies were composed of a fifth element.

Aristotle's physics is incompatible with Newton's first law of motion.