The vital power of an imaginative work demands a diversity within its unity; and the stronger the diversity, the more massive the unity. Incidentally, this is the weakness of most “edifying” or “propaganda” literature. There is no diversity. The Energy is active only in one part of the whole, and in consequence the wholeness is destroyed and the Power diminished. You cannot, in fact, give God His due without giving the devil his due also.

— The Mind of the Maker by Dorothy L. Sayers