Did Socrates really exist? Here is how a lister in another online community penned it:
We have none of Socrates own writings, and it is unclear whether he ever wrote anything.
As for the teachings ascribed to him, they could simply have been made up by Plato and others (anyone who has ever read Plato's Socratic Dialogues would probably be amazed at thinking that Plato could ever memorize all those phrases/arguments/illustrations of Socrates and the others) for the purpose of justifying their own beliefs/philosophy/way of life/etc.
And, as for the very few sources outside of Plato that make mention of Socrates, those mentions most likely are interpolations by followers of Plato, and if not, are simply a re-iteration of the fairy-tale they had already heard from Plato, and not grounded in actual independent sources.
[P]erhaps a man named "Socrates" did exist, but certainly he never said anything that Plato ascribed to him. In fact, it's much more logical to assume that his whole life as a philosopher/his teachings were made up by Plato and others, and that his "martyr's death" at the hands of the Athenians was simply an apologetic fable made up to excuse their strange theories/beliefs.
Although such arguments can be articulated, classicists and historians of antiquity do not even entertain the prospect that Socrates was a fictional personage. There are different standards for validating ancient history.