Full Idea
Aristotle's main objection against the materialists (such as Thales and Anaximenes) is that they cannot explain why things change as they do.
Gist of Idea
Materialists cannot explain change
Source
report of Aristotle (Metaphysics [c.324 BCE], 0988b23-) by Vassilis Politis - Aristotle and the Metaphysics 2.4
Book Reference
Politis,Vasilis: 'Aristotle and the Metaphysics' [Routledge 2004], p.61