  Despite its several virtues, Xenophanes’ physical theory appears to have had little impact on later thinkers. Anaxagoras followed his lead on the nature of the rainbow (cf. DK 59 B19) and Empedocles knew (but repudiated) his claim of the earth’s indefinitely extended depths (DK 31 B39). But both Plato and Aristotle appear to have ignored Xenophanes’ scientific views or assigned them little importance. One factor that may have contributed to this chilly reception was the absence of any expression by Xenophanes of the kind of commitment to teleology that both Plato and Aristotle regarded as essential to a proper understanding of the cosmos. Xenophanes’ universe is controlled by a set of forces, but it is never described as “heading toward the best” nor is it directed toward some best result by a controlling intelligence. (Xenophanes’ divine does “shake all things” by the thought of his mind (alone), but he is never described as in any way directing or controlling particular events.) It is also obvious that Xenophanes’ heavenly bodies would have fallen far short of the level of perfection that, with Aristotle, became a hallmark of classical astronomical theory. Not only are Xenophanes’ heavenly bodies not divine beings, they undergo creation and destruction at regular intervals. Only from the perspective of a much later period can the merits of Xenophanes’ scientific views be fairly appreciated. Many centuries would have to pass before an emphasis on direct observation and the use of entirely natural causes and forces would become the scientific orthodoxy.