Editing Anaximenes of Miletus (section)

== Philosophy ==
{{See also|Classical element#Hellenistic philosophy}}

=== Air as the ''arche'' ===
What is known about Anaximenes's philosophy is what was preserved by later philosophers, particularly [[Aristotle]] and [[Theophrastus]].{{Sfn|Lindberg|2007|p=28}} According to their writings, each philosopher of the Milesian School was a material [[monist]] who sought to discover the ''[[arche]]'' ({{Langx|grc|[[wikt:ἀρχή]]|lit=beginning, origin|links=no}}), or the one, underlying basis of all things.{{sfn|Lindberg|2007|p=29}} This is generally understood in the context of a substance, though scholars have argued that this may be anachronistic by imposing the Aristotelian notion of [[substance theory]] on earlier philosophy.{{Sfn|Algra|1999|p=57}} Anaximenes argued that the ''arche'' is air.{{Sfn|Sandywell|1995|pp=175–176}} He described several basic elements that he considered to be manifestations of air, sorting them from least dense to most dense: fire, air, wind, clouds, water, earth, and stones. Philosophers have concluded that Anaximenes seems to have based his conclusions on naturally observable phenomena in the [[water cycle]]: the processes of [[rarefaction]] and [[condensation]]. He proposed that each substance is created by condensation to increase the density of air or by rarefaction to decrease it.{{Sfn|Eisman|2007|p=76}}{{Sfn|Graham|2006|p=46}}{{Sfn|Sandywell|1995|p=176}} The rarefaction process described by Anaximenes is often compared to [[felting]].{{Sfn|Kočandrle|2019|p=112}}

Temperature was of particular importance to Anaximenes's philosophy, and he developed an early concept of the connection between temperature and density. He believed that expanded air was thinner and therefore hotter while compressed air was thicker and therefore colder—although modern science has found the opposite to be true. He derived this belief from the fact that one's breath is warm when the mouth is wide while it is cold when the air is compressed through the lips.{{Sfn|Vamvacas|2009|p=46}}{{Sfn|Algra|1999|p=59}}

[[File:Anaximenes of Miletus Drawing.jpg|thumb|left|Anaximenes of Miletus as depicted in the ''[[Nuremberg Chronicle]]'' (1493)|220px]]
Anaximenes further applied his concept of air as the ''arche'' to other questions.{{Sfn|Sandywell|1995|p=180}} He believed in the ''[[physis]]'', or natural world, rather than the ''theo'', or divine world.{{Sfn|Sandywell|1995|p=173}} Anaximenes considered air to be divine in a sense, but he did not associate it with deities or personification.{{Sfn|Algra|1999|p=53}}{{Sfn|Vamvacas|2009|p=47}} He presented air as the [[first cause]] that propelled living systems, giving no indication that air itself was caused by anything.{{Sfn|Algra|1999|p=53}}{{Sfn|Sandywell|1995|p=176}} Anaximenes also likened the soul to air, describing it as something that is driven by breath and wills humans to act as they do.{{Sfn|Graham|2006|p=47}} These beliefs draw a connection between the soul and the physical world, as they suggest that they are made of the same material, air.{{Sfn|Sandywell|1995|p=184}} From this, Anaximenes suggested that everything, whether it be an individual soul or the entire world, operates under the same principles in which  things are held together and guided by the air.{{Sfn|Algra|1999|p=59}} In [[Ancient Greek]], the words for wind and for soul shared a common origin.{{Sfn|Vamvacas|2009|p=47}}{{Sfn|Sandywell|1995|p=183}}

Anaximenes's philosophy was centered on a theory of change through ongoing cycles, defined by the movement of air.{{Sfn|Graham|2006|p=45}}{{Sfn|Sandywell|1995|p=180}} These cycles consisted of opposite forces interacting with and superseding one another. This is most prominently indicated in the weather and the seasons, which alternate between hot and cold, dry and wet, or light and dark.{{Sfn|Graham|2006|p=45}} Anaximenes did not believe that any substance could be created or destroyed, only that it could be changed from one form to another.{{Sfn|Graham|2006|p=49}} From this belief, he proposed a model in which the qualitative traits of a substance are determined by quantitative factors.{{Sfn|Vamvacas|2009|p=46}}{{Sfn|Sandywell|1995|p=180}}

===Cosmology and weather===
[[File:Astrologia_(Sterrenkunde)_De_zeven_vrije_kunsten_(serietitel),_RP-P-BI-6393.jpg|thumb|300px|''[[Astrology]]'' by the 16th-century Dutch engraver [[Cornelis Cort]] has a book labeled "Anaximenes" (bottom left).]]
Anaximenes believed that the universe was initially made entirely of air and that liquids and solids were then produced from it through condensation.{{Sfn|Martins|2020|p=37}} He also used air to explain the nature of the Earth and the surrounding celestial bodies. He believed in a [[flat Earth]] that emerged as one of the first things to be condensed from air. This Earth is supported by the pressure of air underneath it to keep it afloat.{{Sfn|Dye|2014|pp=74–75}} 

Anaximenes considered celestial objects to be those which had separated from the Earth.{{Sfn|Kočandrle|2019|p=102}} The philosophers who recorded Anaximenes's ideas disagree as to how he theorized this happened. He may have described them as evaporating or rarifying into fire.{{Sfn|Kočandrle|2019|pp=103–104}} He is said to have compared the movement of the Earth, Sun, and stars to leaves floating in the wind, though he is also described as likening the stars to nails embedded in the sky. Some scholars have suggested that Anaximenes may have believed both models by distinguishing between planets and stars, which would make him the first person to do so.{{Sfn|Dye|2014|pp=74–75}}{{Sfn|Kočandrle|2019|p=102}} While the Sun is described as being a flame, Anaximenes thought it was not composed of rarefied air like the stars, but rather of Earth. According to [[Pseudo-Plutarch]], Anaximenes thought that its burning comes not from its composition, but rather from its rapid motion.{{Sfn|Kočandrle|2019|p=102}}

Anaximenes rejected the commonplace idea that the Sun went underneath the Earth, instead saying that it rotated around the Earth. [[Hippolytus of Rome|Hippolytus]] likened it to a hat spinning around a person's head.{{Sfn|Couprie|2018|p=99}} It's unknown whether this analogy was of Hippolytus's own creation or if it was part of Anaximenes's explanation.{{Sfn|Kočandrle|2019|p=104}} This model of the sun's movement has been interpreted in various ways by subsequent philosophers.{{Sfn|Couprie|2018|pp=99–130}}{{Sfn|Kočandrle|2019|pp=105–106}}

Anaximenes also described the causes of other natural phenomena. Like Anaximander, he believed that thunder and lightning occurred when wind emerged after being trapped in a cloud.{{Sfn|Martins|2020|p=37}} Earthquakes, he asserted, were the result of alternating drying and wetting of the earth, causing it to undergo a cycle of splitting and swelling.{{Sfn|Alexander|2020|loc=Chapter 7}} He was the first philosopher to attempt a scientific explanation of rainbows, and the only one to do so until Aristotle. He described them as a reflection of sunlight off of clouds, and he theorized that the various colors were caused by an interaction of light and darkness.{{Sfn|Naylor|2023|p=47}}

=== Milesian context ===
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Anaximenes's views have been interpreted as reconciling those of his two predecessors, Thales and Anaximander. Air as the ''arche'' is a limitless concept, which resembled Anaximander's theory that the ''arche'' was the abstract infinite that he called ''[[apeiron]]'' ({{Langx|grc|[[wikt:ἄπειρος|ἄπειρον]]|links=no}}, lit. 'unlimited, 'boundless'). At the same time, air as the ''arche'' was a defined substance, which resembled the theory of Thales that the ''arche'' was water.<ref name=":0">{{Harvnb|Algra|1999|p=57}}</ref> Anaximenes adopted a similar design of a flat Earth as Thales. Both proposed that the Earth was flat and that it rested on the substance they believed made up all things; Thales described a disc on water, while Anaximenes described a disc on air.{{Sfn|Algra|1999|p=55}}{{Sfn|Dye|2014|pp=74–75}} His cosmology also did not diverge significantly from the ideas of Anaximander, only changing it so that it reflected his variety of monism.{{Sfn|Dye|2014|pp=74–75}}{{Sfn|Eisman|2007|p=76}}

Anaximenes's philosophy was founded upon that of Anaximander,{{Sfn|Dye|2014|pp=74–75}} but tradition holds that he was also critical of his instructor in some areas.{{Sfn|Sandywell|1995|p=172}} Anaximenes also maintained that there must be an empirical explanation for why substances change from one form to another.{{Sfn|Vamvacas|2009|p=45}}

Anaximenes and Anaximander were similar in that they are not known to have justified why or how changes in physical things take place the way that they do.{{Sfn|Graham|2006|pp=45–46}}{{Sfn|Algra|1999|p=58}} Anaximander instead invoked metaphors of justice and retribution to describe change, and he made direct appeals to deities and the divine in support of his beliefs. Anaximenes deviated from Anaximander in both of these ideas.{{Sfn|Sandywell|1995|pp=172–174, 179}}