G. W. F. Hegel, Lectures on the Proofs of the Existence of God…
“ Not only is it very difficult to have a clear and definite consciousness of what abstraction is and what is the nature of its inner connection, but this power of abstraction is itself the real danger, and this is a danger which is unavoidable when abstraction has once appeared, when the believing human spirit has once tasted of the Tree of Knowledge, and thought has begun to spring up within it in the free and independent form which peculiarly belongs to it. ”
