Socrates was real, but didn't invent doubt
Socrates was mentioned by two separate contemporary historians - Thucydides of his Peloponnesian War service, Xenophon of a courageous stand against the Assembly, so I tend to think he was real.
Now, it's also probably true that his name was taken by other Athenian intellectuals, both as advertising, and as a handy extra in socratic dialogues. The practice even persists today.
I think the ideas of doubt and of placing faith in observable facts must precede Socrates by at least a generation, because there's a generation of great Greek men of Socrates' generation whom all made great progress in arts and sciences that very way. They included Thucydides, whom invented modern history, Socrates himself, and Democritus, originator of atomic theory. All also preceded Aristotle on the scene by atleast eight decades.
Socrates was mentioned by two separate contemporary historians - Thucydides of his Peloponnesian War service, Xenophon of a courageous stand against the Assembly, so I tend to think he was real.
Now, it's also probably true that his name was taken by other Athenian intellectuals, both as advertising, and as a handy extra in socratic dialogues. The practice even persists today.
I think the ideas of doubt and of placing faith in observable facts must precede Socrates by at least a generation, because there's a generation of great Greek men of Socrates' generation whom all made great progress in arts and sciences that very way. They included Thucydides, whom invented modern history, Socrates himself, and Democritus, originator of atomic theory. All also preceded Aristotle on the scene by atleast eight decades.