"Religious" and "mystical" experience are words with many important meanings, some of which are compatible with each others, some of which are not.  Perhaps the most common sort of religious experience that people are allowed to talk about these days (in some circles) is "meeting with the Lord" or "accepting Jesus Christ".  This is thought to be inter-personal, a social event.  Some religious people claim religious "visions". Some  "religious" experiences, a garden-variety kind, are simple awarenesses of receiving some spiritual energy from God ("God's grace").  Many people are simply aware of the presence of God in a contemplative state produced by reading the Bible or by the ancient practice (now common) called "centering prayer" or receiving the host at Mass or in a group meditation such as a Quaker meeting. Note: the word "centering" there is not the same sort of experience as what is often called "focusing" which results in a somewhat similar experience, but the latter is often not described as "religious". 

See --  semantic problems are emerging already.

Then there are the experiences which are called "mystical", a particularly opaque term.  I'd say that generally this word is used for experiences which are way out of the ordinary, ranging from, for instance, the extremely intense visions of some medieval women to a very different sort of experience of the sort described as a self-less experience of a personal, transcendent God-Who-Is-Love.  The latter are the experiences of the Christians Teresa of Avila, of the Muslim Junayd and of the Hindu writer of the Gita. 

The important point is that not all mystics describe the object of their experience as God, or Love, or even as personal, or transcendent.  One does not find such personal objects among the objects of Buddhist experience, extraordinary as those experiences are. though the object of their ultimate experience does seem to transcend this world (though I could easily be wrong :-)  (And note that I'm assuming -- perhaps improperly -- that there is *only one* object of their ultimate experience.)

So I urge you scientists, before you study "religion" or "mysticism" or   "transcendence" to study first the many important meanings those words have among the great mystics.  Unfortuantely, however, the scholars of mysticism generally lump all mystics together, and assume that all of the experiences are fundamentally the same.  But some of the greatest mystics among the Christians and Muslims and Hindus warn us that not all of these experiences and the consequent world-views are the same  Some, such as the Christian Ruysbroeck, the Muslim Qushayri, and the Hindu Ramanuja, have had *several different kinds* of  experiences which are called *mystical*, and they warn us not to confuse them.  They say to do so runs the risk of confusing the depths of the inner self with God -- that depth of self is so extraordinarily beautiful it can be confused with God, but, they tell us from their own experiences, it is not God.  Worse, to confuse those depths of self with God sometimes results in the mystics' identifying themselves with God.  Consequently they consider themselves greater than us lesser humans (they are, after all, God -- they say), and they  become proud and indifferent to others in the world.  (See the Quietists among the Catholics.) 

What I say above is based on the work of the late R.C. Zaehner, professor of comparative religion at Oxford.  His work was and remains extremely controversial. If you're interested in his theory, read his _Mysticism: Sacred and Profane_ (Oxford), or his paperback of related articles, _Zen, Drugs, and Mysticism_.  He's certainlly not entirely consistent over the years, but I think the evidence he brings from all sorts of religious traditions (from the writings of the mystics *themselves*) might convince you that a great deal more work needs to be done on distinguishing these sorts of experience which are called "mystical".  If you lump them together and say you're researching "religious" or "mystical" or "transcendent" experience it would be like saying you're going to be a physicist and then limiting your studies to hydrogen.

This is the murkiest field you can study.  There is no map of consciousness whereby we can distinguish these sites of experience.  (Richard Ornstein made such a map, but I think it's inadequate.)  The "neurotheologians" seem to be making headway in studying one of the kinds of experiences which Zaehner describes (the kind he himself had).   Unfortunately they think they are covering the whole field, but I fear they are not.  Their assumption, I think it is extremely unfortunate both for science and religion because the type of experience they are studying seems to be the kind that Zaehner himself had and according to him is the same sort of experience found in many schizophrenics.  (Yes, he dismisses his own "mystical" experience as identical with or "first cousin to" such schizophrenic thinking.  Honest man.) 

This kind of mystical experience is an irrational one in that the mystic identifies a *part* of the cosmos (i.e., the self) with the *whole* of the cosmos. It seems to me that to accept such experiences as having noetic value spells the death of both science and religion.  By the way, one of the neurotheologians has identified that part of the brain involved in those experiences, and has shown that when the experience takes place that part of the brain is either non-functioning or mis-functioning.   (Or at least that's the last I read about it a couple of years ago.)  That part is used in distinguishing one's own body from the rest of the perceived physical world. Nevertheless that scientist accepts the nonsense (the I-am-part-of-the-whole-and-I-am-the-whole) as an intuiton of some sort of ultimate reality.  I hope the Piagetians won't make the same mistake, and I beg you to please define your terms as carefully as possible.

(By; Ann Olivier)