Most of what we know about Socrates comes from the writings of Plato; however, it is widely believed that only some of Plato's dialogues are verbatim accounts of conversations or unmediated representations of Socrates' thought. Many of the dialogues seem to use Socrates as a device for Plato's thought, and inconsistencies occasionally crop up between Plato and the other accounts of Socrates; for instance, Plato has Socrates constantly denying that he would ever accept money for teaching, while Xenophon's Symposium clearly has Socrates stating that he is paid by students to teach wisdom and this is what he does for a living. Given the apparent evolution of thought in Plato's dialogues from his early years to his middle and later years, it is often believed that the dialogues began to represent less of Socrates and more of Plato as time went on. However, the question of exactly what aspects of Plato's dialogues are representative of Socrates and what are not is far from agreed upon.

Karl Popper treats the Socratic problem in his first book of The Open Society and Its Enemies (1945).