Zen is to religion what a Japanese “rock garden” is to a garden. Zen knows no god, no afterlife, no good and no evil, as the rock-garden knows no flowers, herbs or shrubs. It has no doctrine or holy writ: its teaching is transmitted mainly in the form of parables as ambiguous as the pebbles in the rock-garden which symbolise now a mountain, now a fleeting tiger. When a disciple asks “What is Zen?”, the master’s traditional answer is “Three pounds of flax” or “A decaying noodle” or “A toilet stick” or a whack on the pupil’s head.

ARTHUR KOESTLER, "A Taste of Zen," Bricks to Babel