Mysticism is the attempt to draw near to God by inward disposition rather than by rites or ceremonies.
Mysticism is a way to attain knowledge which is close to philosophy, except that in philosophy you go horizontally while in mysticism you go vertically.
Mysticism is contrasted with the philosophy in that while the Absolute of the metaphysician remains an impersonal and unattainable diagram, the Absolute of the mystics is lovable, attainable, alive.
Mysticism is the seat of the germ of all art and all true science. Anyone to whom this feeling is alien, who is no longer capable of wonderment and lives in a state of fear is a dead man.
Mysticism occurs whenever a human being sees the separation overcome between the natural and the supernatural, between the temporal and the eternal.
Mysticism is the love of truth when it leaves the merely intellectual sphere (i.e. philosophy), and takes on the assured aspect of a personal passion.
Mysticism is the idea that the eye through which one sees God is the same eye through which God sees oneself: as such, one's eye and God's eye are one eye, one seeing, one knowing, one love.