No, Socrates very likely existed. He was mentioned not just by Plato and Aristophanes, but also a number of other contemporaries: Ion of Chios, Eupolis, Ameipsi

No, Socrates very likely existed. He was mentioned not just by Plato and Aristophanes, but also a number of other contemporaries: Ion of Chios, Eupolis, Ameipsias, and Xenophon. We also have references to contemporary accounts by Antisthenes, Aischines of Sphettos, and Aristippos of Kyrene. His trial was also mentioned by Aischines. It's a popular theory on the web but it is a difficult one to justify when we have so much evidence to the contrary, and I'm aware of no serious historian who supports that view.