"Plato... was not present at the conversation... in the Phaedo. Did any philosopher ever propound a new theory of his own by representing it as already familiar to... distinguished living contemporaries? It would be rash... to ascribe the theory to Sokrates, and there seems nothing... but to suppose that the doctrine of “forms” originally took shape in Pythagorean circles, perhaps under Sokratic influence. ... Simmias and Kebes were not only Pythagoreans but disciples of Sokrates; for... Xenophon has included them in his list of true Sokratics."