Thales of Miletus c. 624 BC – c. 546 BC

Thales of Miletus was an ancient Greek Pre-Socratic philosopher of the 7th and 6th centuries BC, traditionally regarded as the first philosopher of the Western tradition and a founder of Greek natural philosophy and mathematics. He held that water is the fundamental substance from which all things arise, the first recorded attempt in the West to explain the world by appeal to a single natural principle rather than to mythology. He is reported to have predicted a solar eclipse in 585 BC and to have demonstrated several geometrical theorems including the equality of base angles in an isosceles triangle. He was counted in antiquity among the Seven Sages of Greece. He left no writings; his views survive in reports by Aristotle and later authors.