So how do people know when they’ve had a mystical or religious experience? The answer is they simply do, mainly because it’s too transcendentally different from any other everyday experience. But what about the rest 99.9% of us who don’t? Is there any way we can be given signposts to act as guides? William James, the early 20th century physician turned philosopher who wrote the seminal Varieties of Religious Experience considered to be one of the most important works on the psychology of religion, was the first to try. He described four qualities that are usually associated with such incidents.

In the ‘simplest’ sort of mystical experience there is always a very strong sense of significance and knowledge associated with the occurrence. There is what he called a noetic quality attached. The word comes from the Greek nous, the image of the absolute good, containing the cosmos of intelligible beings where all other things partake in a portion of everything. It is the principle of the cosmic mind responsible for the order of the cosmos. It also means relating to consciousness or intuition. The mystical, cosmic and holistic connotations are used to refer to the exploration of personal or universal consciousness.

The second and third characteristics which mark and experience as mystical are ineffability and transience. James asserted that due to its hugely subjective nature the experience is much like a state of feeling – for instance, the feeling of being in love or being overwhelmed by a sunset – which just cannot be described in rational terms or words, without resorting to metaphor. Moreover, the experience also fades quickly and is hard to recall, remaining just out of reach. However, some memory content always remains, and this can be used to modify the inner life of the subject.

The fourth quality which defines a mystical state of consciousness is that during the occurrence, individuals do not seem to actively process the information. Instead, it’s a nearly passive experience. Even though many people actively study and / or practice techniques to produce such mystical states, once it happens, the experience seems to happen without their will. The closest other “normal” analogy we can think of are near-death and out-of-body experiences and dreams – all of which are considered by many to be precursors of mystical states of being.