"The most highly developed branches of the human family have in common one peculiar characteristic. They tend to produce--sporadically it is true, and often in the teeth of adverse external circumstances--a curious and definite type of personality; a type which refuses to be satisfied with that which other men call experience, and is inclined, in the words of its enemies, to "deny the world in order that it may find reality." We meet these persons in the east and the west; in the ancient, mediaeval, and modern worlds. Their one passion appears to be the prosecution of a certain spiritual and intangible quest: the finding of a "way out" or a "way back" to some desirable state in which alone they can satisfy their craving for absolute truth. This quest, for them, has constituted the whole meaning of life."
- Underhill, Evelyn. Mysticism: A Study in the Nature and Development of Spiritual Consciousness. New York: Dover Publications, 2002. https://amzn.to/2C91xNY.