Editing Pre-Socratic philosophy (section)

====Anaximenes====
{{Main|Anaximenes of Miletus}}

Little is known of Anaximenes' (585–525 BC) life. He was a younger contemporary and friend of Anaximander, and the two worked together on various intellectual projects. He also wrote a book on nature in prose. Anaximenes took for his principle ''aēr'' (air), conceiving it as being modified, via thickening and thinning, into the other [[classical element]]s: fire, wind, clouds, water, and earth. While his theory resembled that of Anaximander, as they both claimed a single source of the universe, Anaximenes suggested sophisticated mechanisms in which air is transformed to other elements, mainly because of changes of density. Since the classical era, he was considered the father of naturalistic explanations. Anaximenes expanded Anaximander's attempt to find a unitary cause explaining natural phenomena both living and nonliving, without, according to James Warren, having to "reduce living things in some way to mere locations of material change".{{sfnm|1a1=Warren|1y=2014|1pp=33-37|2a1=Sandywell|2y=1996|2pp=172-173}}