One way to define mysticism is to identify the set of typical mental experiences that mystics report to have had. Thus, scholars have made efforts at identifying these characteristics. One scholar, Walter Terence Stace, identified a set of phenomena said to be common in mystical experiences. Another researcher, Ralph W. Hood, Jr., later took Stace's characteristics and constructed a questionnaire which attempted to measure the degree of mystical experience that a subject filling out the questionnaire has had. Hood's scale includes 8 mystical characteristics, each derived from Stace's book, Mysticism and Philosophy. Hood's scale remains popular today as a means of measuring mystical experience.
The 8 mystical attributes in Hood's scale are:
1. Ego Quality: Refers to the experience of loss of sense of self while consciousness is nevertheless maintained. The loss of self is commonly experienced as an absorption into something greater than the mere empirical ego.
2. Unifying Quality: Refers to the experience of the multiplicity of objects of perception as nevertheless united. Everything is in fact perceived as "One."
3. Inner Subjective Quality: Refers to the perception of an inner subjectivity to all things, even those usually experienced in purely material forms.
4. Temporal/Spatial Quality: Refers to the temporal and spatial parameters of the experience. Essentially both time and space are modified with the extreme being one of an experience that is both "timeless" and "spaceless."
5. Noetic Quality: Refers to the experience as a source of valid knowledge. Emphasis is on a nonrational, intuitive, insightful experience that is nevertheless recognized as not merely subjective.
6. Ineffability: Refers to the impossibility of expressing the experience in conventional language. The experience simply cannot be put into words due to the nature of the experience itself and not to the linguistic capacity of the subject.
7. Positive Affect: Refers to the positive affective quality of the experience. Typically the experience is of joy or blissful happiness.
8. Religious Quality: Refers to the intrinsic sacredness of the experience. This includes feelings of mystery, awe, and reverence that may nevertheless be expressed independently of traditional religious language.
In the future we might have a more objective way of quantifying mystical experiences. Such methods might involve non-invasive brain scans and other physiological measures.
-- Nonjohn
Excellent sources to view well-written literature on mysticism can be found at www.bodysoulandspirit.net and www.csp.org.