17th century print of Thales of Miletus (624-546 BC), Ancient Greek philosopher with a poem by Roman poet Decimus Magnus Ausonius. Thales lived at Miletus, an Ionian Greek city in what is now Turkey. He was a pre-Socratic philosopher, regarded by many (including Aristotle) as the first in the Greek tradition and thus of Western thought. He was the first to attempt to explain natural phenomena without recourse to mythology. His use of deductive reasoning, establishing general principles and formulating hypotheses is the basis of modern science. He was the first person to apply deductive reasoning to geometry and is considered the first true mathematician. Print by Dutch engraver Jacob de Gheyn III in 1616.