One of the most important Presocratic philosophers was the Sicilian Empedocles. He presented his work in the form of two hexameter poems, of which about 450 lines are extant, revealing a formidable range of interests, acute observation, and a firm grasp of fundamental issues in the study of man and nature.
Empedocles' theory of four elements was crucial to later developments in science and medicine. He showed how forces of attraction and repulsion acted on the elements within a framework of cyclical time and limited space, and initiated or advanced major discoveries in astronomy, biology,...