Well I wouldn't be surprised if this answer is vetoed as "original research", but there is likely a strong vein of pessimism running running through English language modernism.
I think you can see this in Yeats' poetry, in Eliot, and in a way Pound too ("Oh my England"). All the important artists were writing about the modern condition, and post its beginnings in the so called "fin de siecle" absorption of the French avant garde, the former of which I think enjoyed their apocalyptic and godless fate, modernism does tend to strike me as quite bitter, if not resigned.
I tend to read the grand aesthetic questions through Adorno's confusion on the failure of the Russian revolution, which sees the modern world as thoroughly awful, and finds redemption only in the (illusory) criticism of it, through art. He wrote on Beckett, especially, when dealing with literature as opposed to music.
So we have here anyway, a skepticism, without faith. And the enlightenment was in the thrall of both, I think, placed interior to the other anyway.