Anaximenes

Anaximenes of Miletus, who lived around 586 to 526 BC, was a pre-Socratic Greek philosopher from Miletus in Anatolia and the last of the three philosophers of the Milesian School, after Thales and Anaximander, regarded by historians as the first philosophers of the Western world. He is known for his belief that air is the arche, the basic element of the universe from which all things are created, holding that air could change into other forms through rarefaction or condensation: condensation would make air denser, turning it into wind, clouds, water, earth and finally stone, while rarefaction would make it less dense until it became fire. Anaximenes also developed a model of the Earth as a flat disc floating atop the air, with the Sun and stars also flat and floating alongside it, revolving around the Earth. He influenced many of the pre-Socratic philosophers who succeeded him, including Heraclitus, Anaxagoras and Xenophanes, and provided early examples of natural science and scientific writing.