I believe that the ancient Greeks' measurement of the sun's distance showed great sophistication. Given that fire was something everyone was familiar with and they knew how rapidly heat diminished as one walked away, is there any record of speculation that the heat of the sun came from something other than a large wood (since I believe that was what Greek's burned) fire?

  • $\begingroup$ It would be both helpful and interesting to know what is referred to in the first sentence, "I believe that the measurement..." Is it to ancient Greeks' measurement of the distance? Or something else? Please clarify. $\endgroup$
    – DJohnson
    Commented Jul 1 at 2:00

1 Answer 1


...is there any record of speculation that the heat of the sun came from something other than a large wood (since I believe that was what Greek's burned) fire?

The Presocratics proposed numerous monist theories grounded in their notion of arche, "that of which all existing things are composed and that from which they originally come to be and that into which they finally perish... this they state is the element and principle of the things that are."

For Thales, the arche of the cosmos is water though no recorded fragment describes how it was believed that fire arises from water.

For Anaximander, the arche of the cosmos is apeiron, "'(that which is) unlimited; boundless; infinite; indefinite'." Aristotle wrote that Anaximander said the sun was "pure fire", suggesting that fire is elemental (as was later argued by Empedocles vis-à-vis earth, air, fire, and water.)

For Anaximenes, the arche of the cosmos is aer, "somewhat loosely translated as 'air', but meaning a sort of dense air or vapour." Anaximenes said that the sun was air refined into fire. Plutarch writes:

As Anaximenes of old believed, ... he declares that the condensed state [of air] is cold whereas what is fine and 'loose' (calling it this way with this very word) is hot. As a result he claimed that it is not said unreasonably that a person released both hot and cold from his mouth. For the breathe becomes cold when compressed and condensed by the lips, and when the mouth is relaxed the escaping breathe becomes warm because of rareness.

"The observation that air blown through pressed-together lips is cool, but warm when exhaled from an open mouth is verifiable: one can do the simple experiment and feel the proof of the back of one's hand. This shows that Anaximenes views were an attempt to make sense of observation, and doing so in a systematic, inclusive theory that brought all phenomena together into a single explanatory framework."

(Quotes are take from Grayling's History of Philosophy)


For Xenophanes the arche was fire and like Anaximander, he believed that the sun(s) were pure fire. Xenophanes had a wonderfully idiosyncratic cosmology which Grayling summarizes: "... he thought that the earth extended indefinitely downwards, and that therefore the sun could not circle beneath it at night. Instead there is a new sun every day, gathered together out of 'many small fires'."


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