The fact that we still group all his predecessors together as ‘presocratics’ indicates that Socrates significantly changed the character of philosophy. Yet it is not easy to determine exactly what change Socrates made, much less why. Socrates himself left no record of his thoughts, so we have to refer to the writings of the three authors who knew him. But in the Clouds Aristophanes depicts ‘Socrates’ as a ‘sophist’ who taught cosmology as well as rhetoric, i.e. as a ‘presocratic’. In (...) his Memorabilia Xenophon merely declares that Socrates did not investigate the nature of all things or the cosmos. To find out when and why Socrates turned to study the human things, we have to put together three retrospective statements he gives about his development as a philosopher in Plato’s dialogues. Working on the basis of the supposed chronology of composition, scholars have not done so. (shrink)