On the Heavens

What It's About

On the Heavens (De Caelo) is Aristotle's principal treatise on cosmology. In it he lays out his theory of the physical universe: the four terrestrial elements (earth, water, air, fire), each with its own "natural" motion, and a fifth element, aether, of which the heavens themselves are made. From this he builds an argument for a finite, spherical, geocentric universe in which the heavenly bodies move eternally in perfect circles.

Key Concepts

Central ideas include the doctrine of natural place and motion, the distinction between the corruptible sublunary world and the incorruptible heavens, the eternity and finitude of the cosmos, and the argument that circular motion is the only motion capable of being perpetual. The work also addresses the shape and size of the earth and the order of the celestial spheres.

About the Author

Aristotle (384–322 BC) was a Greek philosopher born in Stagira. He studied under Plato at the Academy in Athens for some twenty years before later founding his own school, the Lyceum. He tutored the young Alexander the Great and became one of the most influential thinkers in the history of Western philosophy and science.

About This Edition

This is a 1922 translation by J. L. Stocks.