America's great psychologist, William James provided a description of the mystical experience in his famous collection of lectures published in 1902 as The Varieties of Religious Experience. In Lectures 16 and 17 he stated:
"...propose to you four marks which, when an experience has them, may justify us in calling it mystical...:
1. Ineffability - The handiest of the marks by which I classify a state of mind as mystical is negative. The subject of it immediately says that it defies expression, that no adequate report of its contents can be given in words.
2. Noetic Quality - Although so similar to states of feeling, mystical states seem to those who experience them to be also states of knowledge. They are states of insight into depths of truth unplumbed by the discurssive intellect. They are illuminations, revelations, full of significance and importance, all inarticulate though they remain; and as a rule they carry with them a curious sense of authority for aftertime.
3. Transiency - Mystical states cannot be sustained for long.
4. Passivity - Although the oncoming of mystical states may be facilitated by preliminary voluntary operations, as by fixing the attention, or going through certain bodily performances, or in other ways which manuals of mysticism prescribe; yet when the characteristic sort of consciousness once has set in, the mystic feels as if his own will were in abeyance, and indeed sometimes as if he were grasped and held by a superior power.