What must be the first step of the self upon this road to perfect union with the Absolute? Clearly, a getting rid of all those elements of normal experience which are not in harmony with reality: of illusion, evil, imperfection of every kind. By false desires and false thoughts man has built up for himself a false universe: as a mollusc, by the deliberate and persistent absorption of lime and rejection of all else, can build up for itself a hard shell which shuts it from the external world, and only represents in a distorted and unrecognisable form the ocean from which it was obtained. This hard and wholly unnutritious shell, this one-sided secretion of the surface-consciousness, makes as it were a little cave of illusion for each separate soul. A literal and deliberate getting out of the cave must be for every mystic, as it was for Plato’s prisoners, the first step in the individual hunt for reality.

Underhill, Mysticism

Double points: Absolute sounds like Kierkegaard, and Plato’s cave is a great metaphor for the spiritual life.