ca. 625-ca. 547 B.C.
Thales of Miletus is sometimes called the father of philosophy*. Aristotle considered him the founder of natural philosophy because he was the first Greek thinker who attempted to understand the physical basis of the universe. Before Thales, people had used mythology to explain the natural world. Thales also gained fame as an astronomer, engineer, and mathematician.
Because Thales left behind no written works, most of what is known about him is based on the writings of Aristotle, Plato, and others. Born in Miletus in Asia Minor, Thales was active in the political affairs of his home city. According to the historian Herodotus, he advised Miletus and other Greek cities in Asia Minor to join together to defend themselves against the Persians.
Thales spent time in Egypt, where he calculated the height of the pyramids by measuring the length of their shadows. He also studied the causes of floods along the Nile River. Herodotus claimed that Thales accurately predicted the solar eclipse that occurred in 585 B.C.
In studying the natural world, Thales claimed that water was the basic element of the universe and that all things came from it. Two philosophers from Miletus who came after Thales—Anaximander and Anaximenes—continued his quest to find answers to questions about the nature of the universe.
Thales also had great practical knowledge, which inspired Plato to include him in his list of the Seven Sages, or wise men—men whom Plato believed represented the ancient wisdom of Greece. Thales was widely considered to be a genius, and his name became synonymous with exceptional intelligence. (See also Greece, History of; Ionians; Philosophy, Greek and Hellenistic.)
* philosophy study of ideas, including science