Parmenides is great. If memory serves: the One, the Way of Opinion, deductive method versus "common sense."
Nietzsche talks about the "noble taste" of these counter-sensual presocratics. Common sense has its merits in regards to practical matters, but what about philosophy as an art?
Didn't Parmenides write his work in verse? He was explicitly a poet, implicitly a mystic (or so I might argue). And yet explicitly a rationalist (is this the right word?) using the deductive method. Maybe even some language philosophy implicit in his presentation.
Forgive any errors. It's been awhile. But I have always love the pseudo-monotheist sequence of Parmenides, Spinoza, Hegel.
Kojeve writes brilliantly on all of them in his book on Hegel.