These words have to do with matter beyond the range of one’s ordinary knowledge, perception or understanding, with the added suggestion of things kept secret or hidden from all but an initiated few. Mystical emphasizes the idea of a direct, intuitive, deeply personal revelation, especially one of a spiritual or religious nature: the mystical visions of Saint Teresa of Avila; John Donne’s mystical poems; a mystical belief in life after death.

An occurrence or phenomenon is mysterious if it contains elements that arouse one’s wonder, stimulate one’s curiosity, and baffle one’s efforts to explain it: the mysterious universe; a mysterious ailment; the mysterious properties of a new drug. Here the possibility of a rational explanation remains, the obscurity being the result of inadequate rather than unobtainable knowledge.

Occult , as the word suggests, means hidden or concealed and has come to be applied chiefly to magical arts and practices, such as astrology, alchemy, divination. These who were versed in such secret matters were said to have occult powers, not to be freely divulged to others and exerted only under special conditions, usually determined by themselves. Thus, while one may speak of an experience as mysterious where the causes are unknown but ascertainable, as mystical when it is unique, spontaneous and usually incommunicable, occult implies some agency unknown in human experience without whose deliberate intervention something would not have occurred.