Thales of Miletus was a philosopher, astronomer, and statesman from the Ionian city of Miletus in the 7th–6th centuries BCE. He is traditionally regarded as the first philosopher in the Greek tradition and one of the legendary Seven Sages.
The precise dates of his life are uncertain, but ancient sources place his most famous achievement—the prediction of a solar eclipse—around 585 BCE. He was also known as a practical engineer and a political advisor. No writings by Thales survive, and scholars debate whether he composed any texts at all. What is known of his ideas comes from later reports by philosophers like Aristotle.
According to these sources, Thales initiated a new way of inquiry, seeking a single, fundamental principle behind all things. He famously proposed that water, water, was this single principle, his archē. He is also credited with introducing geometrical knowledge, geometry, to Greece and with establishing basic theorems.
Thales stands at the head of Western science and philosophy. He is considered the first of the Milesian school, whose seekers gave non-mythological explanations for the cosmos. His work marked a decisive turn toward investigating the world through observation and argument.
Available Works
Also published as PDF.