Greek philosopher who was a subscriber to the Pythagorean school of natural philosophers, but without the mysticism of his contemporaries. He felt that we must use the data from our senses, even though they could not be completely trusted. He believed the Moon shone by reflected light. He postulated that all substances were made up of air, earth, fire, and water combined in different proportions. He is the first to have suggested the humoral theory, later adopted by the Hippocratics. He also proposed a crude theory of evolution.

Hippocrates of Cos, Pythagoras

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