Anaxagoras was born about 500 BCE in Clazomenae and died in Lampsacus in 428 BCE. He moved to Athens after the Persian wars and stayed there until exiled in 430 BCE. He was a follower of Anaximenes. He argued that the senses do not provide us with the truth because of their feebleness in discriminating subtle changes. He may have written the first philosophical treatise to contain diagrams. He believed that everything in the universe is composed of small uniform bodies which contain parts of every other type of stuff. All the objects that exist now are complex and consist of parts of everything else. Whatever we perceive an object to be is often what that object has most of. For example, what we call fire is made mostly of fire but also has a little bit of air and water, etc. Snow is mostly made of whiteness but also has a little bit of blackness and everything else, etc. He proposed that the origin of the universe began when everything, which was compacted down into an indistinguishable mass, began to rotate and expand and throw out elements, the sun, the stars, the moon and the earth. Denser regions separated from the less dense, hotter from the colder, the drier from the wetter, and the lighter from the darker. The heaviest, most condensed, most moist, and coldest bodies are lowest and the lightest, hottest, driest, and most rarefied bodies are the highest, so that Earth is the lowest, then water, then air, and uppermost is fire. He believed the universe is continuing to expand and will in the future. The original source of all movement and organization is thought, but then there is also a mechanistic interaction between physical objects and of air, ether, water, and others. This thought is eternal and is not physical. He argued that the sun and stars are fiery stones, that the moon and stars are made of earth and shine by reflective light from the sun and believed in the correct explanation of solar eclipses, and that all the heavenly bodies are kept in place by their rapid rotation. He also believed that there are mountains and ravines on the moon and also that there is intelligent life there and throughout the universe. He believed that rainbows are caused by the reflection of the sun in the clouds.

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