Plato refers frequently to the views held by the early Greek thinkers we today call ‘the Presocratics’, typically while lining up witnesses for or against a philosophical thesis. His characters speak approvingly of the doctrines of Parmenides and the Pythagoreans but repudiate in the strongest terms the teachings of ‘atheistic materialists’ such as the Milesian inquirers into nature we today regard as the founders of Western philosophy and science. The chief failings of the materialists lay in not acknowledging the priority of soul over matter and not believing that a cosmic intelligence has arranged all things for the best. On occasion, Plato states a view held by a thinker he has elsewhere criticized and he is not above borrowing the idea...