His book on Materialism and Empiric Criticism (1909) heaps abuse on idealistic philosophers and religious teachers of all schools and creeds.
The Erasistrateans paved the way for what was in some respects the most important school which Alexandria produced, that known as the empiric, which, though it recognized no master by name, may be considered to have been founded by Philinus of Cos (280 B.C.), a pupil of Herophilus; but Serapion, a great name in antiquity, and Glaucias of Tarentum, who traced the empirical doctrine back to the writings of Hippocrates, are also named among its founders.
Anatomy was as little regarded as it was in the later ancient schools, the empiric and methodic, but demonstrations of the parts of the body were given on swine.
The extent to which his practice was influenced by this and other a priori conceptions prevents us from classing Sydenham as a pure empiric; but he had the rare merit of never permitting himself to be enslaved even by his own theories.
During the middle ages the empiric spirit was in abeyance, but it revived from the time of Francis Bacon and was systematized especially in the English philosophers, Locke, Hume, the two Mills,.