Ferenczi #8, your question about "attain to" ("the 'to' in 'attain to' is not correct here, or is it") -- I don't think it's incorrect (in the OED it's listed as meaning #10) but, as I mentioned at #7, the OED does classify it as "archaic".
Arguably there's a slight shift of nuance from "attain" to "attain to":
(A) "to attain consciousness of his own sentiments"
(B) "to attain to consciousness of his own sentiments"
Although the meaning of "arriving at consciousness of" is contained in (A), it also has the sense of "acquiring consciousness of" or "getting consciousness of" -- for my feel in fact it's the dominant sense.
In the case of (B) only the sense of "arriving at consciousness of" is involved. And for that reason it seems to me preferable to (A), even at the price of its being a mild archaism (which, given the fact that it's Goethe, I would think is defensible).
[On top of that, just to make things nice and complicated ;-), if you were to use "attain" on its own, I don't think it would fit in with the remainder of the beginning of the sentence as I've given it:
"The highest man can attain is consciousness of his, etc."
I would be inclined then to jettison "attain" entirely and use, say, "achieve":
"The highest man can achieve is consciousness of his, etc."
But, imo the version with "attaining to" is far preferable to this, simply because of the notion of arriving at, of reaching, rather than that of acquiring, of getting, or achieving. But now I'm repeating myself.]