Thales of Miletus (c.624–c.545 BCE) was a Greek natural philosopher who founded the Ionian school of ancient Greek thinkers. Thales is one of the Seven Sages of ancient Greece and was considered by Aristotle to be the founder of physical science; that is to say, he was the first Greek to search for the ultimate substance of things, which he identified with water.
Despite crediting Thales for moving Western thought from the realm of myth to the rigor of empiricism, historians have no direct evidence that he actually existed. It is assumed that Thales was educated by an Egyptian priest and lived in Athens.
A polymath, Thales acquired renowned status as engineer, geometer, and astronomer. He introduced the study of geometry to Greece, and, according to the ancient Greek historian Herodotus, predicted (within a year) the solar eclipse of 585 BCE. Thales is also associated with not only many achievements in geometry and mensuration, but also the study of solstices and astronomical seasons, and the development of many hypotheses concerning the physical world.