Thales

Thales of Miletus (c. 624–546 BCE) was an ancient Greek thinker from Miletus in Ionia who made influential contributions to philosophy, geometry, and astronomy. Often considered the first philosopher in the Western tradition, he is counted among the Seven Sages of Greece and is regarded as a founder of natural philosophy, which sought explanations of the natural world without relying on myth or supernatural causes.

In natural philosophy, Thales proposed that water is the underlying principle, or arche, of all matter. This idea positioned him within the Milesian school, alongside Anaximander and Anaximenes, as they pursued a single, natural basis for reality. In geometry, he is associated with early deductive reasoning and theorems, including the proposition that a triangle inscribed in a semicircle is a right triangle, commonly known as Thales’ theorem. He is also credited with applying geometric methods to practical problems, such as estimating the height of pyramids from their shadows.

Ancient sources attribute to Thales the prediction of a solar eclipse in 585 BCE, though modern historians debate the reliability of this claim and its dating. His approach emphasized rational explanation and natural causes, influencing later Greek philosophers and the development of scientific thought.

In contemporary usage, the name Thales also refers to the Thales Group, a French multinational corporation specializing in defense, aerospace, and transportation technologies.

Overall, Thales is remembered as a foundational figure in early Greek thought, noted for advancing naturalistic approaches to understanding the world and for contributions to geometry.