Derived Light and Eclipses in the Fifth Century

Abstract

In a study earlier in this volume, ‘The Relation of Anaxagoras and Empedocles’, pp. 93–113, I listed the ancient evidence to the effect that Anaxagoras first gave the correct explanation of an eclipse, and that he was followed in this by Empedocles. A more extensive examination of the evidence raises certain difficulties. For what are, or might appear to be, Anaxagoras' theories are attributed elsewhere to earlier thinkers.There are two principal elements in this contradiction, the one direct and the other indirect.1. There is a direct contradiction when Thales, Anaximenes and some Pythagoreans are said to have given the correct explanation of an eclipse, at least if we suppose the Pythagoreans in question to have been earlier than Anaxagoras.2. There has been thought to be an indirect contradiction when several thinkers before Anaxagoras are said to have derived the moon's light from the sun. For a theory of derived light for the moon has been thought, whether rightly or wrongly, to entail the correct explanation of an eclipse.In what follows I shall attempt to solve these, and some other incidental difficulties.