Reason, belief, ground, argument. Fitche, Schelling, Hegel, and Schopenhauer all held the same philosophy after you put unnecessary details away. They are materialists and turn their mind to idealist psychology and *will* over the brute reality, although they could not deny that their life was purely biological. It is good to insist on a soul and all the idealist stuff is fascinating in its own way. The only trust idealists thinkers are people like Berkeley who came from a truly religious perspective. I imagine Hegel was happier than materialista who were more blunt ( "honest") who rejected him as con act. If you like, you could say he had more faith.
Lastly, Kant was a little different. He seemed to have a mind like Descartes but more into logic than math and incapable of finding a logic to believe in the way Descartes did.