Anaximenes of Miletus (ˌænækˈsɪməˌniːz; Ἀναξιμένης ὁ Μιλήσιος; 586/585-526/525 BC) was an Ancient Greek, Pre-Socratic philosopher from Miletus in Anatolia (modern-day Turkey) active in the 6th century BC. He was the last of the three philosophers of the Milesian School, regarded by historians as the first philosophers of the Western world. Anaximenes is best known and identified as a younger friend or student of Anaximander, who was himself taught by the first philosopher in the Greek tradition, Thales, one of the Seven Sages of Greece.
The life and views of Anaximenes remain obscure as none of his work has been preserved, and he is only known through comments about him made by later writers. Historians and philosophers consider his cosmological views to be similar to his two Milesian predecessors. Thales proposed that all matter was made of water; Anaximander proposed all matter was made of apeiron—something indefinite rather than something specific; and Anaximenes proposed that a