dark fanaticism, abstract rationalism

To the true conception of religion are equally repugnant the dark fanaticism which holds on to a single partial revelation, a single positive form, and denies all others; and the abstract rationalism which resolves the whole essence of religion into the fog of indefinite concepts and merges all religious forms into one empty, impotent, and colorless generality.

—Vladimir Solovyov, Lectures on Godmanhood (1876)