Thales' theory was refuted by his successor and esteemed pupil, Anaximander. Anaximander noted that water could not be the arche, because it could not give rise to its opposite, fire. Anaximander claimed that none of the elements (earth, fire, air, water) could be arche for the same reason. Instead, he proposed the existence of the apeiron, an indefinite substance from which all things are born and to which all things will return. "Apeiron" (endless or boundless) is something completely indefinite and Anaximander was probably influenced by the original "chaos" of Hesiod (yawning abyss). He probably intended it to mean primarily "indefinite in kind" but assumed it also to be "of unlimited extent and duration". The notion of temporal infinity was familiar to the Greek mind from remote antiquity in the religious conception of immortality and Anaximander's description was in terms appropriate to this conception. This "arche" is called "eternal and ageless". (Hippolitus I,6,I;DK B2)