Anaximenes

Anaximenes of Miletus was an Ancient Greek philosopher from Miletus in Anatolia, who lived from approximately 586/585 to 526/525 BC. He was the final member of the Milesian School, following Thales and Anaximander, and is recognized as one of the earliest Western philosophers. Much of what is known about Anaximenes comes from later writings, as his original works are lost. His central philosophical idea was that air is the arche, the fundamental element from which everything originates. He proposed that air transforms into other substances through processes of rarefaction (becoming thinner and hotter, like fire) and condensation (becoming denser and colder, like wind, clouds, water, earth, and stone). This concept of change through physical processes was a significant step in the development of natural philosophy. Anaximenes also developed a cosmology, describing the Earth as a flat disc floating on air, and the celestial bodies as similarly flat and revolving around it. He is credited with influencing later Pre-Socratic thinkers and laying groundwork for scientific writing.