Many great characters have a guide. Homer was Virgil’s guide, Virgil was Dante’s guide, Morpheus was Neo’s guide. Both Morpheus and Virgil were men of cracked faith, spoiled by what they didn’t know, disillusioned by revelation. It’s interesting that Faust’s guide wasn’t Dante. Nor was the great Earth Spirit Faust’s guide because he was unworthy of such a great spirit. Instead God chose the most unlikely character imaginable to be Faust’s guide, the spirit of negation, a devil named Mephistopheles.
Why though? Mephisto is an unwitting instrument of god’s in the fact that he can’t experience love at all, so why him? Why not the Earth Spirit? The Earth Spirit and Faust are both symbolic of the perpetual forward thrusting of reality, of constant creation which is emblematic of German Romanticism. But why Mephisto? He’s a man of the world, and I mean *this* world. Not heaven or hell, but here on Earth. Mephistopheles negates all the possibilities until Faust’s striving soul realizes the divinity within himself, which is found when we de-individuate ourselves to become part of the whole, which is God’s eternal purpose.
So the solipsist opens up at the end. I want to note that Werther was a solipsist too, but here with Faust, Goethe has a resolution, and its ending isn’t an ordinary tragedy but optimistic, that we can find heaven on Earth, and that even a man who has dark strivings, but who is led by a higher power, can find salvation.