I agree, dear Maximius, that it is difficult with systems, and I certainly know of Schopenhauers Kritik der Kantischen Philosophy, where he pours mockery over the fellow philosopher for his urge to systematize symmetrically.

But apart from that: I thing Plato had some fundamental ideas, which reflect through his writing. And one is the idea about the ideals. Another would be the idea that everybody had his optimal place in society and that society could be really well if only...

But of course Plato had also a lot of thoughts on contemporary problems and tackled those individually and without founding every declaration on a fixed system.

And for the title of the thread: I am not so sure that Plato worked much on epistemology. At least in comparison to Kant ...