Anaximenes (ănˌəksĭmˈĭnēz) [key], Greek philosopher, 6th cent. B.C., last of the Milesian school founded by Thales. With Thales he held that a single element lay behind the diversity of nature, and with Anaximander he sought a principle to account for diversity. He believed that single element to be air. The principle of diversification he taught was rarefaction and condensation. Different objects were therefore merely different degrees of density of the one basic element. Anaximenes anticipates the spirit of modern scientific practice that seeks to explain qualitative differences quantitatively.
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