He also played an importqant role in the development of the Western or Sicilian school of Greek medicine.
He cured a plague at the Sicilian city of Selinus and claimed he was a god.
Heraclitus - Greek philosopher; first of the Greeks to develop a theory of the human soul; he praised its creative resources and spoke of the importance of self-exploration; he spoke of the logos that is common to all and said that the universe is ruled by logos; he always urged that close attention be given to the polarites and concealed structures emodied in language.
His famous claim that an idividual can and cannot step into the same river twice reveals an interest in criteria of unity and identity; even though all material constituents have undergone change, it is still, in a sence, the same river.
Issac Newton - English mathematician and scientist; developed theory of matter; first to demonstrate the color components of white light with a prism and the reconstruction of these colors into white light with a second prism; researched the optical characteristics of chemical substances; studied gravitation and motion; developed the law of gravitation.