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Anaximenes of Miletus

philosophy religion Maturity 11-13 Next article →

Anaximenes of Miletus was an Ancient Greek philosopher from Miletus in Anatolia.

Miletus agora
Miletus agora

He was the final member of the Milesian School. This group included the thinkers Thales and Anaximander. Historians consider these three men the first philosophers of the Western world. They were the first to seek material origins for the universe. They did not rely on divine explanations for how the world began. Anaximenes is primarily known for his theory regarding the arche. The arche is the single, foundational substance of all things.

Anaximenes of Miletus Drawing
Anaximenes of Miletus Drawing

Anaximenes argued that air was the arche. He was a material monist. This means he believed one single substance made up everything. He explained how air transforms into other substances through two specific processes. The first process is called condensation. This occurs when air becomes denser and thicker. Condensation turns air into wind, clouds, water, earth, and stone. The second process is called rarefaction. This occurs when air becomes less dense and thinner. Rarefaction turns air into fire.

Astrologia (Sterrenkunde) De zeven vrije kunsten (serietitel), RP-P-BI-6393
Astrologia (Sterrenkunde) De zeven vrije kunsten (serietitel), RP-P-BI-6393

Anaximenes used physical observations to support his ideas. He developed an early concept regarding the link between temperature and density. He believed that expanded air was thinner and hotter. He believed that compressed air was thicker and colder. He likely derived this from observing human breath. Breath feels warm when the mouth is wide open. Breath feels cold when it is compressed through the lips. This idea shows he sought empirical, observable explanations for natural changes. He believed that substances could not be created or destroyed. They could only change from one form to another.

His cosmology included a specific model of the Earth and heavens. Anaximenes believed the Earth was a flat disc. He claimed the Earth floated on the pressure of the air underneath it. He described the Sun and stars as flat objects floating alongside the Earth. He thought the Sun was made of Earth rather than rarefied air. He believed the Sun's heat came from its rapid motion. He also thought the Sun revolved around the Earth. He compared this movement to a hat spinning around a person's head.

Miletus agora
Miletus agora

Anaximenes also provided early scientific explanations for weather and light. He believed thunder and lightning happened when wind was trapped in clouds. He thought earthquakes resulted from the Earth swelling and splitting. This happened during cycles of wetting and drying. He was also the first to attempt a scientific explanation of rainbows. He described them as sunlight reflecting off clouds. He thought the colors came from the interaction of light and darkness. These theories moved away from myths toward natural science.

Historical records of his life are quite limited. Most of what we know comes from later writers like Aristotle and Theophrastus. Diogenes Laertius recorded that Anaximenes lived from approximately 585 to 524 BC. He was likely a student of Anaximander. Some suggest he was the son of Eurystratus. Anaximenes may have been wealthy, which allowed him time for study. He likely studied Greek mythology and Homeric epics. These studies might have influenced his views on the classical elements. He wrote one full text, possibly a response to Anaximander's work.

Anaximenes holds a significant place in the history of thought. He reconciled the ideas of his predecessors. Thales believed the arche was water. Anaximander believed it was the apeiron, or an undefined infinity. Anaximenes chose a substance that was both defined and limitless like air. He influenced many later Pre-Socratic philosophers. These included Heraclitus, Anaxagoras, Diogenes of Apollonia, and Xenophanes. He helped develop the prototype for scientific writing. He used descriptive prose instead of verse. His work helped establish the foundations of Western natural science.

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File:Miletus agora.jpg
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