We have generally proposed that there are two classes of neuropsychological mechanisms which underlie the development of religious experiences and behaviors. These two classes of mechanisms represent two lines of neurological development involving the evolution of brain structures that comprise what we have previously referred to as the causal operator on the one hand and the holistic operator on the other. "Operators" refer to networks of nerve tissue in the brain which perform specific functions — in the first case allowing us to perceive causality and in the second allowing us to perceive wholeness in the midst of diversity. There is growing evidence that such overarching functions exist in the brain. In considering these two operators, we are led to the heart of why human beings use the concept of supersensible forces or powers (i.e. the concept of a deity) to help control their environment in such a way as to attain those needs which the culture defines as fundamental. Furthermore, these operators allow for the movement towards the fulfillment of human needs in a total, absolute, or transcendent fashion, often involving holistic states or experiences.

It has now become possible to consider asking questions regarding how complex behaviors, thoughts, and feelings occur, even when they are associated with religious and spiritual experience. Our research has been devoted to elucidating the nature of these experiences by determining their underlying biological mechanisms. In fact, in our recent book, The Mystical Mind: Probing the Biology of Religious Experience , we consider these very questions. Perhaps the most interesting question of all is where exactly a neuropsychological approach leads us, and where do we go from there.

Can religion and spirituality be considered purely as "neural blips and fluxes in brain chemistry"? Using recent advances in brain imaging and neuropsychological research, co-authors Dr. Andrew Newberg and the late Dr. Eugene D'Aquili, both of the University of Pennsylvania, explore that question and arrive at some surprising conclusions about material and spiritual "reality." This article, adapted for Science & Spirit magazine from their 1999 book The Mystical Mind: Probing the Biology of Religious Experiences , presents an overview of some of their findings.

Two cognitive scientists examine the biological mechanisms underlying religious and spiritual experience.

Based on our model presented in prior works as well as our book, it seems that all unitary experiences — ranging from mild aesthetic experiences such as watching a beautiful sunset to the most profound states that may occur only after years of meditation — may have their basis in neuroanatomy, neurophysiology, and the flux of neurotransmitters. We have even suggested that there is an aesthetic-religious continuum that is based upon the progressive activation of the holistic operator such that the more profound the experience, the greater the sense of unity. Our recent brain imaging studies of Tibetan Buddhist meditators have begun to provide empirical evidence for the specific mechanisms involved in this continuum of experiences.

Many find it deeply disturbing that the experience of God, the sense of the absolute, the sense of mystery and beauty in the universe, the most profoundly moving experiences of which humans are capable, might be reducible to specific brain functions that may even be measurable on advanced brain imaging studies. However, such a pessimistic interpretation misses a few rather important points. First of all, our experience of baseline reality (e.g., chairs, tables, love, hate), indeed of our whole physical and psychological environment, can also be reduced to neural blips and fluxes of brain chemistry. Thus, one can never get at what is "really out there" without its being processed, one way or another, through the brain. So what criteria can we use to evaluate whether God, other hyperlucid unitary experiences, or our everyday world is "more real"? Can we use our subjective sense of the absolute certainty of the objective reality of our everyday world to establish that that world is "really real"?

To simplify the issue somewhat, let us for the moment contrast the most extreme unitary state, what we have called Absolute Unitary Being (AUB), with baseline reality. AUB refers to the rare state in which there is a complete loss of the sense of self, loss of the sense of space and time, and everything becomes a infinite, undifferentiated oneness. Such a state usually occurs only after many years of meditation. In comparing AUB to baseline reality, there is no question that AUB wins out as being experienced as "more real." People who have experienced AUB, and this includes some very learned and previously materialistically oriented scientists, regard AUB as being more fundamentally real than baseline reality. Even the memory of it is, for them, more fundamentally real. Thus, if we use the criterion of the sense of certainty of the reality of a particular state, AUB wins hands down.

To further clarify this point, let us compare four characteristics of baseline reality with the profound experience of various unitary states. Baseline reality demonstrates the following four fundamental properties:

A strong sense of the reality of what is experienced. Endurance of that reality through very long periods of time, usually only interrupted by sleeping. The sense that when elements in baseline reality disappear from all forms of sensory detection, they have ceased to be. High cross—subjective validation both for details of perception and core meaning. In other words, other people corroborate our perceptions of the world, i.e., reality is a collective hunch.

The essential characteristics of profound unitary consciousness (i.e., AUB) are the following:

An extremely strong sense of reality, to the point of its being absolutely compelling under almost all circumstances. Endurance for short periods of time relative to the sense of time of baseline reality. A sense of its underlying persistence and continued existence even when the perception of the overall state has ended. High cross—subjective validation for core perceptions. Moderate to low cross—subjective validation for perceptual details in those states.

We would maintain that it is impossible to determine whether various unitary states or baseline reality is more real (i.e. which represents the ultimate objective reality) without making gratuitous and unsubstantiated assumptions. Clearly, baseline reality has some significant claim to being ultimate reality. However, AUB is so compelling that it is very difficult indeed to write off the assertion of its reality. Actually, for individuals having experienced AUB, it seems virtually impossible to negate that experience. This being the case, it is a foolish reductionism indeed which states that, because unitary consciousness can be understood in terms of neuropsychological processes, it is therefore derivative from baseline reality. Indeed the reverse argument could be made just as well. Neuropsychology can give no answer as to which state is more real, baseline reality or hyperlucid unitary consciousness often experienced as God. We may be reduced to saying that each is real in its own way and for its own adaptive ends.

Thus, the essential characteristic of different states of reality are eventually reducible only to the strength of the sense of reality, the phantasia catalyptica of the Stoics, or the Anwesenheit (compelling presence) of certain modern German philosophers. A vivid sense of reality may be the only thing that we can use to help determine what is really real until someone determines a method for going beyond the brain's perception of reality. This conclusion may not be very epistemologically satisfying, but up to now any alternative has escaped us.

In The Mystical Mind, we explore the concept of neurotheology as a way to help better answer the epistemological question raised above — is AUB or baseline reality more real? It might ultimately be best to consider both versions of reality to be complementary, rather than opposed, to each other.

However, this conclusion also has important implications for religion, theology, and the scientific study of religious experiences. As a field, the neuroscientific analysis of religious and spiritual experiences is only in its infancy. Much more research must be pursued before we can begin to better understand these complex experiences. However, we are at least able to begin such an exploration as well as consider the consequences. The result — one hopes — will be a wonderful journey that will enlighten ourselves as well as the scientific study of religious experience.

Reprinted with permission from Science & Spirit magazine (www.science-spirit.org).