The last words of Socrates were: Crito, I owe a cock to Asclepius; will you remember to pay the debt?
In other words he was talking about the gods. He talked about the gods a lot. Talk about the gods is all over Plato - pretty much everything gets related back to the gods, sooner or later. And philosophy is footnotes to Plato.
When, and why was it decided that it made sense to do philosophy without the gods? That it made sense to be a Platonist, but not believe in the gods?
Of course, this entails deciding what was meant by talking about the gods - and when I was an atheist I simply assumed that because I couldn't take the gods seriously, then neither did Socrates and Plato. Or even if they did 'believe in' the gods, this was merely a shallow and conventional conformity to the contingent culture of their world.
But it does seem that without the gods, the whole thing falls apart - without the gods philosophy seems to be just a matter of opinion, playing with ideas, this metaphor or that...
But if Socrates was serious, and the most important thing in the world as he approached death was to sacrifice to one of the gods - the god of doctors - then we ought to assume that the gods were the foundation of Socrates most profound beliefs. And also of Plato - and therefore of philosophy.
Take away the gods and philosophy falls to pieces.
And this is what we find.