[This is an entry to the 2019 Adversarial Collaboration Contest by Jeremiah Gruenberg and Seth Schoen]

1. Introduction

This project seeks to explore the viability of spiritual or religious experiences as empirical evidence for a component of reality that transcends or is radically different from our ordinary experience. The question at hand is not the existence of God or higher powers, nor the failures, successes, or benefits of religion, but rather the role of spiritual experience in the human understanding of the nature of reality. We formulated the topic in controversy this way:

The empirical study of the content and nature of people’s personal spiritual experiences justifies taking them seriously as evidence of an important component of human life deserving of individual and collective exploration.

Our fellow human beings have always had unusual experiences that they found special and meaningful, but often struggled to interpret or place in the context of their ordinary lives. These experiences and their interpretation have aroused intense controversy, both because people have deployed them as support for their views on contested issues about the nature of reality, and because they may arise in settings where one could easily question whether the brain’s altered perceptions and understandings are enhanced or impaired. Another source of debate is how radically different individuals’ experiences—and their personal interpretations of the origins and meanings of those experiences—can be. Finally, spiritual experiences are often reported through a cultural lens that leads to questions about how accurately and objectively people could perceive and describe the unusual things that they perceived.

We emphasize that there is no question, even from the most skeptical perspective, of insisting that individuals alter their own views or memories of what they have witnessed (although we encourage people to question their interpretations and to become aware of factors that could raise doubts about those interpretations). What is rational or plausible for each person to believe at a particular moment can be different, and in any case the way that people interpret their own experience and history will be different. If you have had a spiritual experience whose nature and meaning you find evident and certain, others may offer you alternative interpretations and evidence against your view, but can’t demand that you change it. However, we find it interesting to consider what lessons others can draw from accounts of unusual experiences and perceptions: not so much what sort of evidence your own spiritual experiences may constitute for you, but rather what sort of evidence your accounts of them may constitute for others. Can we collectively learn anything from these experiences?

One objective of this project is to explore empiricism as a key to a “common language” which allows all perspectives to discuss the significance of spiritual experience—not just those who are predisposed to a traditional theistic model of reality. Empiricism seems to a major contender in the competition to find common ground surrounding spirituality. It is both experience-based and rational. Properly employed, the use of empiricism may allow for a rational discussion of personal experience.

We’ve structured this article in nine sections:

Introduction. Definitions of Empiricism, Experience, Knowledge, and Spirituality: a discussion of some important terms, as well as the coherence and conflict between empiricism and rationality. Psychological Research on Spiritual Experience. Epistemology and Religious Experience: this section focuses on William P. Alston’s treatment of how mystical perception may justify the generation of personal belief. Near Death Experiences: a review and discussion of a major work on the significance of NDEs from the perspective of a scholar who suggests that their meaning is largely symbolic. The Use of Entheogens: a look at a recent meta-study which reviews the data of five different studies on spiritual experiences resulting from the use of entheogenic substances, and some other sources on entheogens in religion. The Problem of Dreaming: an objection to the interpretation of spiritual experiences as having anything other than personal, momentary significance. Some Possible Perspectives: the collaborators share their various ideas on how the empirical and philosophical content of the paper thus far might be viewed or understood. Concluding Thoughts.

2. Definitions of Empiricism, Experience, and Spirituality

The first step in exploring this statement is interact with philosophical perspectives on the interrelated concepts of empiricism, experience, and spirituality in the attempt to define our terms.

Empiricism can be various defined. Essentially it deals with sensory experience as a generator of knowledge.

Empiricism was an integral—perhaps the singular fundamental—of the emergence of scientific inquiry as we know it. Wolfe and Gal write:

It was in 1660s England, according to the received view, in the meetings of the Royal Society of London, that science acquired the form of empirical enquiry that we recognize as our own: an open, collaborative experimental practice, mediated by specially-designed instruments, supported by civil, critical discourse, stressing accuracy and replicability. Guided by the philosophy of Francis Bacon, by Protestant ideas of this-worldly benevolence, by gentlemanly codes of decorum and integrity and by a dominant interest in mechanics and a conviction in the mechanical structure of the universe, the members of the Royal Society created a novel experimental practice that superseded all former modes of empirical inquiry – from Aristotelian observations to alchemical experimentation.

However, it is important to note that empiricism was popularized as a philosophical concept in the first half of the 20th Century (by such figures as A.J. Ayer, Rudolf Carnap, Kurt Gödel, Karl Popper, Hans Reichenbach, and Ludwig Wittgenstein), and began to take various shapes. Since then, there have been major disagreements on exactly what empiricism entails and how it functions. However, the Stanford Encyclopedia of Philosophy states: “Since antiquity the idea that natural science rests importantly on experience has been non-controversial.”

Perhaps most germane to the topic of this investigation is the fact that empiricism conflicts with pure rationality. It is easy to recognize the limitations and failings of human experience as a reliable source of truth. However, since all inputs to human cognition are fundamentally experiential in nature (e.g. the senses of sight, hearing, etc.), the issue of experience must be addressed in any epistemological mode.

In reviewing this conflict between rationalism and empiricism, Markie summarizes the empiricist position with this thesis: “We have no source of knowledge in S or for the concepts we use in S other than sense experience.”

On the other hand, Markie provides three theses which summarize the rationalist position:

The Intuition/Deduction Thesis: Some propositions in a particular subject area, S, are knowable by us by intuition alone; still others are knowable by being deduced from intuited propositions.

The Innate Knowledge Thesis: We have knowledge of some truths in a particular subject area, S, as part of our rational nature.

The Innate Concept Thesis: We have some of the concepts we employ in a particular subject area, S, as part of our rational nature.

Taking these views into consideration, it seems that the human being is still left in an empiricist position in that our existential state precludes non-experiential data gathering. Intuition itself is formed by lifelong experiences. Nor is “our rationalist nature” is as purely rational as we might hope. Certainly, we should temper the negative subjective qualities of experience, but it seems impossible to circumvent experience altogether regarding embodied human epistemology.

It is true that our experiences must be tempered with objective rationality. However, most humans naturally function primarily in an empirical manner in the formation of worldview, beliefs, and knowledge. The relevant question is therefore not whether some form of empiricism is at play in epistemology in general, but what its role should be. It seems the pure rationalist would exclude all subjective experiential sources of knowledge, even if humans naturally engage in—and rely on—such subjective experiential sense-making.

When it comes to issues of spirituality, a materialistic presupposition would immediately dismiss all appeals to experience. Such a presupposition precludes any engagement with the metaphysical due to its (supposed) nonexistence. A committed materialist would not even investigate the possibility that spiritual experiences have anything but a neurological/biochemical cause. However, if such a presupposition may be suspended, empiricism may hold the key in explaining and/or understanding a spiritual worldview.

What then constitutes “spirituality” in this conversation? The authors of this collaboration would include such experiences as meditative suspensions of self, encounters with the divine in any religious context, near-death experiences, and transcendental uses of entheogens. Spirituality may be theistic, or it may not. Examples of theistic spirituality are easy to come by. An example of a non-theistic approach to spirituality is found in Sam Harris’ Waking Up, which advocates the use of meditation derived from Buddhist practices to attain altered states of consciousness. While we (the collaborators) might individually define spirituality somewhat differently on an individual level, we find this more general approach helpful to foster conversation on the empirical nature of spiritual experience.

Zinnbauer argues that the terms religion and spirituality are very similar in meaning, but that religion is a narrower term as it is limited to a traditional or institutional context. Zinnbauer writes:

Thus, according to these definitions, spirituality is a broader term than religiousness. Spirituality includes a range of phenomena that extends from the well-worn paths associated with traditional religions to the experiences of individuals or groups who seek the sacred outside of socially or culturally defined systems. For example, an individual’s spirituality may include feelings of devotion, memories of a mystical experience, gatherings with other seekers, rebellion against a culture antagonistic to such a search, and a sense of unity with all sentient life. Significant changes in any of these levels or developmental strands may change the search itself. Development of a serious illness, for example, may change feelings of devotion to confusion or anger, make gatherings more difficult to attend, and cause psychological isolation from a sacred connection to others.

Pargament provides a slightly different contrast between the two:

In short, spirituality is highlighted as a distinctive dimension of human functioning in the…. Spirituality alone addresses the discovery, conservation, and transformation of the most ultimate of all concerns, the sacred. Yet religiousness is not viewed as inconsistent with or an impediment to spirituality. In fact, spirituality is the core function of religion. Indeed, considerable religious energy is dedicated to helping people integrate the sacred more fully into their pathways and destinations of living. But to succeed at this task, religion accepts and attempts to address the full range of human strivings. Thus, as defined here, religiousness represents a broader phenomenon than spirituality, one that is concerned with all aspects of human functioning, sacred and profane.

However, Zinnbauer and Pargament note that culturally, spirituality seems to be supplanting religion in a few ways. Spirituality is now seen as the encompassing “sacred or existential goals in life, such as finding meaning, wholeness, inner potential, and interconnections with others….” They continue: “In contrast, religiousness is substantively associated with formal belief, group practice, and institutions.”

3. Psychological Research on Spiritual Experience

We were impressed by the existence of numerous empirical psychological studies of spiritual experience. Two recent major works which reveal this breadth of research are The Psychology of Religion: an Empirical Approach by Hood, Hill, and Spilka, and Handbook of the Psychology of Religion and Spirituality, edited by Paloutzian and Park. The significant earlier studies of spiritual experience include those of Harvard psychologist William James (Varieties of Religious Experience: A Study in Human Nature) and Alister Hardy (The Spiritual Nature of Man: Study of Contemporary Religious Experience). “Both James and Hardy affirmed the evidential value of religious/spiritual experiences as at least hypotheses suggesting the existence of a transcendent reality variously experienced.” (James famously suggests that spiritual experiences are difficult to understand or evaluate, but that they are compelling and widespread enough to “forbid a premature closing of our accounts with reality.“)

Paloutzian and Park recognize the limitations of psychological research on the nature of spiritual experience in this way:

our job as scientific psychologists of religion is to create good theory to explain religiousness in a way that allows the theory to be assessed against evidence. This means ideas about possible causal factors that are not, in principle, capable of being tested against evidence may be interesting, but they do not meet the criteria necessary to bear upon our theory construction process.

Current Research

Surveys indicate that somewhere between one third to one half of the population has had some sort of significant religious experience. Such experiences are correlated with gender, education, and social class—being more common for females, for those with a higher education, and for those in higher classes. Hood et al. write: “Women report more such experiences than men; the experiences tend to be age-related, increasing with age; they are characteristic of educated and affluent people; and they are more likely to be associated with indices of psychological health and well-being than with those of pathology or social dysfunction.” Investigations into the heritability of religiosity, particularly through twin studies, place it between 0% to 50%.

It was also discovered that people in the United States, Australia, the United Kingdom, and Scandinavia do not tend to share their spiritual experiences with others. Hood et al. wonder if this is why such spiritual experiences are thought to be uncommon (as fewer people in these societies might have heard reports of others’ spiritual experiences).

Due to the internal and personal nature of spiritual experiences, the data gathering on the topic is most often accomplished through surveys, questionnaires, and interviews. The accuracy of such self-reporting can be measured—with some testing suggesting that some percentage are likely false positives (tendencies both for the pro-religious to affirm spiritual experience and for the anti-religious to deny spiritual experience). Identifying activity which triggers spiritual experience and studying individuals undertaking these actions in a laboratory setting is another research mode. Such activities studied include prayer and meditation. As we will discuss in another section, they also increasingly include the use of psychoactive substances.

Hood et al. admit that the over-reliance on self-reporting is a difficult hurdle in the study of spiritual experience, particularly because of the potential pitfalls of bias, including “intentional deception, impression management, personal bias, and many more.” They discuss the alternative uses of other kinds of measurement, such as physiological and behavioral measures, and the increasing use of the Implicit Association Test.

One study indicated that spiritual experience (reading Psalm 23) functioned neurologically in the frontal and parietal lobes, while nonreligious experience of reading Psalm 23 involved the amygdala (which was not active in the religious experience). “On the basis of these findings, Azari and her coworkers have proposed that religious experience is likely to be a cognitive process utilizing established neural connections between the frontal and parietal lobes.”

Addressing whether spiritual experiences are the result of a psychiatric disorder, Hood et al. note that “both normal and psychotic individuals can have mystical experiences” and that this is backed up by empirical research. Such research noted that the differences between normal mystics and psychotics is that “The psychotic mystics exhibited resistance and rigidity, as opposed to the normal mystics, who exhibited openness and fluidity. Thus it is not simply mystical experience, but the reactions to the experience, that distinguish psychotic from normal mystics.”

The Nature of Spiritual Experience

Some evolutionary psychologists argue that religious experience arose because it is an adaptive advantage. Kirkpatrick writes, “Hypotheses about the adaptive function of such religious instincts have ranged from defense against fear of death or other forms of comfort and anxiety reduction to group-level benefits such as promoting cohesion and solidarity or reducing conflict.” However, Kirkpatrick argues that the evidence does not point to adaptive advantage. He writes, “My own view…is that the diverse collection of phenomena we refer to as ‘religion’ represent a collection of by-products of numerous adaptations with other specific, mundane functions.” Kirkpatrick continues,

With respect to religion, beliefs about the existence of supernatural forces and beings appear to emerge as a spandrel-like by-product of evolved systems dedicated to understanding the physical, biological, and interpersonal worlds (Boyer, 1994, 2001). For example, an evolved agency-detector mechanism, designed to distinguish animate from inanimate objects in the world, can be fooled fairly readily to produce psychological animism and anthropomorphism (Atran, 2002; Atran & Norenzayan, in press; Guthrie, 1993), as when we find ourselves cursing at our aforementioned computer when it crashes. Once these spandrel-like effects enable ideas about gods and other supernatural beings, I have suggested, specific forms of religious belief emerge as by-products of psychological mechanisms dedicated to processing information about functionally distinct kinds of interpersonal relationships—attachments, kinships, dominance and status competitions, social exchange relationships, friendships, coalitions, and so forth—that whir into action to shape specific beliefs and expectations about these beings and guide behavior toward them. Thus, for example, gods might be perceived as attachment figures, dominant or high-status individuals, or social exchange partners, with each possibility leading to a different set of expectations and inferences about those gods’ behavior and decisions about how to best interact with them—processes emerging from functionally distinct psychological systems designed to solve such adaptive problems in human relations (Kirkpatrick, 1999, 2005).

Theories related to agency detection are popular with religious skeptics; some have noted that in a dangerous world of predation or intergroup violence, wrongly failing to perceive agency and intelligence where they are present has greater adverse survival consequences than wrongly perceiving them where they are not present.

Neuropsychologists, however, point to a combination of “cognitive operators” in the brain which together give rise to human religiosity. “The term ‘cognitive operator’ simply refers to the neurophysiological mechanisms that underlie certain broad categories of cognitive function. Thus, these operators do not exist in the literal sense, but can be useful when considering overall brain function.” The “causal operator” works with any series of perceived events and attempts to organize them back to an original cause. Such perception and organization is subjective and may not arrive at an accurate conclusion. Newberg and Newberg write: “We have proposed that when no observational or “scientific” causal explanation is forthcoming for a strip of reality, gods, powers, spirits, or some other causative construct is automatically generated by the causal operator (d’Aquili & Newberg, 1997).” A second operator proposed as functioning in the development of spiritual experience is the “holistic operator”: “The proposed holistic operator permits reality to be viewed as a whole or as a gestalt, as well as the abstraction from particulars or individuals into a larger contextual framework.”

How to View Religious/Spiritual Experience

The following quotes are summaries of current positions of psychologists studying religious and spiritual experience. They represent foundational views in the field and we have chosen therefore to quote them at length.

Hood et al. warn against the danger of reductionism in the psychological study of spiritual experience, stating that it is dangerous “to reduce the richness and complexity of religious experience to a favorite psychological construct.” Elsewhere, they write:

The empirical study of religiousness has many great challenges. The first of these challenges considered here is how to maintain the scientific standards of good empirical work, always the goal of science, without sacrificing the richness and depth of the object of study. We have gone to considerable lengths to make the case that religious experience should not be reduced to specific psychological processes. It is tempting to do so when one adopts the naturalistic perspective that underlies scientific investigation, and to ignore the meaning system of the people being studied. What is needed is some nonreductionistic accounting of the phenomena of interest, but without abandoning scientific methodology and thus not reaping the benefits that it provides. (Hood and Hill Psychology of Religion, 25)

Zinnbauer and Pargament write:

A controversy that often is raised in discussions of measurement and definition is that of reductionism, the process of understanding a phenomenon at one level of analysis by reducing it to presumably more fundamental processes (see discussions in Idinopulos & Yonan, 1994, and Wilber, 1995). In some sense this process is unavoidable in scientific study (Moberg, 2002; Segal, 1994). However, reductionism is often accompanied by a loss of information. For example, the reduction of mystical experiences of oneness with the universe to a change in neurotransmitter levels eliminates information at all other levels (e.g., the cultural, social, familial, affective, cognitive, and behavioral). There may indeed be important physical correlates of such an experience, but to deny the relevance or value of other modes of interpretation and understanding is to commit the error of reductionism.

Regarding the problem of the compatibility of empiricism with the notion of a genuine spiritual reality, Hood et al. write:

Although social scientists cannot confirm any ontological claims based upon mystical experience, they can construct theories compatible with claims to the existence of such realities. Hodges (1974) and Porpora (2006) have argued that the scientific taboo against the supernatural can be broken, as long as hypotheses about the supernatural can be shown to have empirical consequences. In Garrett’s (1974) phrase, “troublesome transcendence” must be confronted by social scientists as much as by theologians and philosophers.

Newberg and Newberg write:

Western society has historically emphasized the importance of causality, technological advances, and empiricism. It is from these values that Western medicine, psychiatry, and psychology have developed. We propose that regardless of the connotation of the concept of spirituality in Western society, mystical and meditative experiences are natural and probably measurable processes that are and can be experienced by a diversity of people of different races, religions, and cultures. Those having spiritual experiences can have a variety of neuropsychological constitutions. In addition, it is important for clinicians to be sensitive and knowledgeable regarding spiritual and philosophical beliefs (Worthington, McCullough, & Sandage, 1996). Professionals need to be capable of distinguishing normal, healthy spiritual growth from psychopathology. We hope that some of the neurophysiological analysis described above might allow for a distinction between “normal” spiritual experiences and pathological states. In fact, such a nomenclature may be valuable for future psychological analysis of religious experiences. However, the fact that spiritual experiences have an effect on autonomic function as well as other cortically mediated cognitive and emotional processes suggests that such experiences not only affect the human psyche, but also can be carefully crafted to assist in the therapy of various disorders. It has already been shown that prayer and meditation can improve both physical and psychological parameters (Carson, 1993; Kabat-Zinn, Lipworth, & Burney, 1985; Kaplan, Goldenberg, & Galvin-Nadeu, 1993; Worthington et al., 1996). The more the underlying neurophysiological correlates of spiritual experiences are understood, the more such experiences can be analyzed and utilized in clinical practice. Therefore, spiritual experience can be very useful in clinical psychological and psychiatric practice. Furthermore, clinicians themselves can be instrumental in helping their patients toward personal and spiritual growth by discussing various meditative and/or spiritual practices and encouraging patients to approach these practices in an unambiguous manner. According to Rowan (1983), a humanistic psychologist, it is the self that is the missing link between the psychological and the spiritual. Therefore, it seems natural that spiritual experiences, such as those encountered in meditation and prayer, could become an adjunct to Western therapeutic practices and that developing oneself spiritually can become an important part of psychosocial as well as neuropsychological development.

Hood et al. continue:

There is no reason why scientists cannot include specific hypotheses derived from views about the nature of transcendent reality in empirical studies of religious experience, as long as specific empirical predictions can be made. The source of the predictions may reference even the unobservable and the intangible. All that is required is that there be identifiable empirical consequences. As Jones (1986) has stated the case, Invoking Occam’s Razor [i.e., the philosophical principle that the best explanation of an event is the simplest one] to disallow reference to factors other than sensory observable ones is question begging in favor of one metaphysics building up an ontology with material objects as basic. (p. 225) Jones echoes the classic claim of William James that mystics base their experience upon the same sort of processes that all empiricists do—direct experience. James would restrict the authoritative value of mystical experience to the person who had the experience, but would view it as a hypothesis for the social scientist to investigate (Hood, 1992a, 1995c). However, mystics are united in the belief that such experiences are real, and many nonmystics are convinced of the reality of the experience even if they personally have not had it. Thus, as Swinburne (1981) argues, mystical experience is also authoritative for others:

. . . if it seems to me I have a glimpse of Nirvana, or a vision of God, that is good grounds for me to suppose that I do. And, more generally, the occurrence of religious experience is prima facie reason for all to believe in that of which the experience was purportedly an experience. (p. 190)

Social scientists are often too quick to boast that their own limited empirical data undermine ontological claims. Religious traditions cannot be adequately understood without the assumption that transcendent objects of experience are believed to be real and foundational to those who experience them (Hood, 1995a). It is also possible that not only are they believed to be real, but that they are in fact real as well. Furthermore, their reality may be revealed in experience. Carmody and Carmody (1996, p. 10) define “mysticism” as “a direct experience of ultimate reality.” This definition remains a hypothesis capable of empirical investigation. To presuppose otherwise is less persuasive than once thought. Bowker (1973), after critically reviewing social-scientific theories of the sense of God, has noted that it is an empirical option to conclude that at least part of the sense of God might come from God. In our terms, religious views of the nature of the Real suggest ways in which it can be expressed in human experience. This can work in two directions, both deductively and inductively. Deductively, one can note that if the Real is conceived in a particular way, then certain experiences of the real can be expected to follow. Thus we can anticipate that expectations play a significant role in religious experience, often confirming the foundational realities of one’s faith tradition. Inductively, we can infer that if particular experiences occur, than the possibility that the Real exists is a reasonable inference—a position forcefully argued by Berger (1979). Thus we can anticipate that experiences, some unanticipated, may lead some to seek religions for their illumination. O’Brien (1965) has gone so far as to include in his criteria for a mystical experience that it be unexpected. Religious traditions adopt both options in confronting mystical and numinous experiences. In this sense, a rigorous methodological atheism is unwarranted in the study of religious and mystical experiences (Porpora, 2006). Not surprisingly, then, mystical experiences have long been the focus of empirical research and provocative theorizing among both sociologists and psychologists. We first explore classic efforts to confront these experiences. These classic views are of more than historical interest, as they set the range of conceptual issues that continue to plague the contemporary empirical study of mysticism. Our focus upon classic views is not exhaustive. We focus upon representatives of three major social-scientific views regarding mystical experience: as erroneous attribution, as a heightened state of awareness, and as evolved consciousness.

4. Epistemology and Religious Experience

Debates about the existence of God have often included the “argument from religious experience”; its advocates may cite their own experiences, or may claim that perceptions of some sort of divinity are a psychological or cultural universal, or nearly so. These arguments may involve evidence such as



The way that many people feel that they have met God or that God has spoken to them.

The way that many people have had some sort of experience or perceptual of a divine or spiritual realm or order. The way that the human tendency to perceive or be interested in these topics (and to believe in, venerate, or attempt communications with deities or spiritual powers) is widespread across cultures, even though their interpretation varies so dramatically. (The notion of “natural religion” has sometimes been justified on the basis of supposedly universal notions among human societies, or supposedly universal experiences shared among human beings who contemplate the idea of the divine. In the view of proponents of this concept, we might have good evidence to believe in God or divinity as a result of widespread human experience of these things, but perhaps not good evidence to believe in specifics about the divine nature, which are much less widely agreed upon.)

While realizing that not everyone who has had a spiritual experience assigns any particular significance or interpretation to that experience, never mind formulating a specific theistic argument on the basis of the experience, we were interested in looking at how this argument is viewed by some of its proponents and opponents. In addition to reading online summary articles about arguments from religious experience, we chose to focus on William P. Alston’s groundbreaking philosophical work on empiricism regarding religious/spiritual epistemology. Alston introduces his book Perceiving God: The Epistemology of Religious Experience in this way:

The central thesis of this book is that experiential awareness of God, or as I shall be saying, the perception of God, makes an important contribution to the grounds of religious belief. More specifically, a person can become justified in holding certain kinds of beliefs about God by virtue of perceiving God as being or doing so-and-so. The kinds of beliefs that can be so justified I shall call "M-beliefs" (‘M’ for manifestation). M-beliefs are beliefs to the effect that God is doing something currently vis-a-vis the subject—comforting, strengthening, guiding, communicating a message, sustaining the subject in being—or to the effect that God has some (allegedly) perceivable property— goodness, power, lovingness. The intuitive idea is that by virtue of my being aware of God as sustaining me in being I can justifiably believe that God is sustaining me in being. This initial formulation will undergo much refinement in the course of the book.

In order to avoid presupposing the existence of God, Alston specifies “the experiences in question as those that are taken by the subject to be an awareness of God (or would be so taken if the question arose).” In this way, it seems Alston is exploring the justification of taking spiritual experience as the basis of forming “M-beliefs” (basically, beliefs formed by mystical experiences) irrespective of whether such beliefs correspond with reality. As Alston states: “I want to make explicit at the outset that my project here is to be distinguished from anything properly called an ‘argument from religious experience’ for the existence of God…. It is rather that people sometimes do perceive God and thereby acquire justified beliefs about God.” In this sense, Alston focuses mainly on the philosophical legitimacy of people treating their own religious and spiritual experience as evidence for belief in the object of those experiences—not on the legitimacy of arguing that others, too, ought to do so.

This distinction is interesting. After all, having religious experiences and adopting specific attitudes with respect to their meaning or implications could theoretically be completely independent, so we could imagine encountering



Someone who has subjectively perceived God but is unsure of whether this experience was veridical or significant, and does not adopt or argue for a view that the perception was necessarily real.

Someone who has subjectively perceived God and is convinced of the reality of that perception (whether or not he or she supposes that others, who haven’t shared this perception, ought to agree).

Someone who has not had such an experience, but finds others’ accounts of their experience persuasive and is inclined to agree with their interpretations. Someone who has not had such an experience and remains skeptical of others’ accounts or interpretations.

Of course, still other nuances are possible.

Alston appears particularly interested in countering those who maintain that individuals ought to rationally discount their own personal experience (especially because they feel that personal experience isn’t the kind of thing that could be rationally convincing in this realm). In some ways, Alston’s approach could be seen as focused on the analysis of individual rationality and not about collective reasoning or persuasion.

In fact, Alston’s views on evidence and belief seem remarkably compatible with other accounts of rationality; it seems that his main point is that experience of the divine is evidence that should lead the experiencer to update his or her beliefs in favor of a greater likelihood that the divine exists—which one would only not do given other priors that the divine is absurd, that perceptions of it are of a different kind of evidential value than other perceptions, or something. So Alston then dedicates long passages to claiming that there’s no philosophical reason that we have to think that these perceptions don’t have a similar evidential value from other kinds of perceptions, and to trying to defeat arguments that they don’t.

We could probably successfully rephrase most of his line of argumentation with a Bayesian-rationalist flavor: “conceptually, there is nothing about the sense of the divine that makes it less rational to use it to update one’s beliefs about the objects of its perception than it would be to use other senses to update one’s beliefs about the objects of their perception.” Of course, how much to update will be largely informed by one’s priors, particularly here about naturalism or materialism, etc. The nut to be cracked here is this: how does rationality work when trying to learn about subject matter that is not perceived through the bodily senses but that presents itself as an analogously coherent or compelling perception? Alston’s position seems to include the notion that, even though we may have very high priors for naturalism, we shouldn’t confuse that with the choice to rule other kinds of perception out-of-bounds for belief updating.

Alston further clarifies his aim in this way:

Even if our age were firmly realist in its predilections, my central thesis would still be in stark contradiction to assumptions that are well nigh universally shared in intellectual circles. It is often taken for granted by the wise of this world, believers and unbelievers alike, that "religious experience" is a purely subjective phenomenon. Although it may have various psychosocial functions to play, any claims to its cognitive value can be safely dismissed without a hearing. It is the purpose of this book to challenge that assumption and to marshal the resources that are needed to support its rejection.

While his argument is very detailed, we present here an overview.

He begins with a discussion on the phenomenology of spiritual experience. After reviewing a few self-reported descriptions of spiritual experience, Alston emphasizes that they all share a common dimension of the experience as being presented to the subject. In this way, Alston likens spiritual perception to natural perception, and distinguishes presentation from abstract thought. He suggests that this aspect of presentation demonstrates that such experiences do not arise internally and are not subjective in their inception. He furthers this point by reviewing several descriptions of spiritual experiences which include sensory perception. Alston’s phenomenology here is one in which “mystical perception” (his preferred term over “spiritual experience”) is a “putative direct experiential awareness of God.”

Alston argues that a “direct awareness” of something—whether physical or mystical—is independent from beliefs, judgment, or concepts of the object of awareness. This is in general accord with Russell’s idea of “acquaintance” and Moore’s idea of “direct apprehension.” However, this view is in contrast with the view initiated by Kant that all perception is mediated by beliefs, judgment, or concepts. Alston argues against this view by stating that there is a difference between a direct awareness of something and the subsequent judgment that the object has some sort of property. In this way, Alston maintains that a person may be aware of an object without interpretational judgment on that object.

The contrary view would easily be employed toward not taking any reports of mystical experiences seriously. If all perception is mediated by belief, then those who believe in God could easily be interpreting a non-spiritual event through their spiritual presuppositions. The argument could be made that the subjects of mystical experiences quoted by Alston are not reliable sources regarding the nature of their experiences. Alston responds to this charge:

It is conceivable that one should suppose that a purely affective experience or a strongly held conviction should involve the experiential presentation of God when it doesn’t, especially if there is a strong need or longing for such a direct awareness. But even if an individual’s account of the phenomenology of his or her own experience is not infallible, it must certainly be taken seriously. Who is in a better position to determine whether S is having an experience as if of something’s presenting itself to S as φ than S? We would need strong reasons to override the subject’s confident report of the character of her experience. And where could we find such reasons? I suspect that most people who put forward these alternative diagnoses do so because they have general philosophical reasons for supposing either that God does not exist or that no human being could perceive Him, and they fail to recognize the difference between a phenomenological account of object presentation and the fact that a certain object, as the subject conceives it to be, presents itself to the subject’s awareness. In any event, once we get straight about all this, I cannot see any reason for doubting the subjects’ account of the character of their experience, whatever reasons there may be for doubting that God Himself does appear to them.

Alston also notes that such experiences should be taken seriously because the subjects themselves consider alternative sources or interpretations for their experiences. In other words, it seems likely that such people remain rational regardless of the sometimes outlandish nature of their experiences, and are aware that their own perception may be at fault. The subjects rejected such alternatives, however, often due to the “presentation” aspect of the experiences—in other words, stating that they did not, themselves, produce the experience.

Alston’s argument proper begins with the notion that spiritual experiences are perceptual in nature. That is, God presents himself to the subject in some manner. He takes that conclusion as the basis for his argument for the reasonability for taking such perceptions to be indicative of true reality. Alston introduces this argument in this way:

If what seems to me to be a direct experiential awareness of X puts me in a position to form justified beliefs about X’s perceptible features, that warrants me in supposing that X itself is indeed presenting itself to my awareness; otherwise how could the experience justify my beliefs about X? We have to stop short of the claim that the perceptual justification of perceptual beliefs entails that the experience is genuine perception. I may be perceptually justified in believing that there is a lake in front of me even if I am a victim of a mirage and no lake is being perceived. But this is just an isolated incident that occurs against the background of innumerable cases in which perceptual justification involves authentic perception of the object. It strains credulity to suppose that an entire sphere of putatively perceptual experience could be a source of justification for perceptual beliefs, while there is no, or virtually no, genuine perception of the objects involved. Therefore, if putative experience of God provides justification for beliefs about God, that provides very strong support for supposing that such experiences are, at least frequently, genuine perceptions of God.

Alston’s concept of justification for belief is that the subject is justified in maintaining his or her belief, rather than the subject’s activity of justification. The difference is that someone may be justified in his or her own beliefs irrespective of attempting to argue for them.

He clarifies his view of justification as indicating favorability of true belief, taking into account that it is a matter of degree. One may be justified in a belief, even if the evidence does not lead one to be completely certain.

Alston’s argument for the justification of M-beliefs is as follows: 1) A perceptual belief concerns a perceived object, no more and no less. In other words, a perceptual belief is that one is sensing a presented object. 2) This belief is formed primarily by an experience of perception (according to the human senses). 3) A perceptual belief is not based on prior beliefs or concepts. Alston writes, “The theory of justification I am using takes justification to be a function of the adequacy of what the belief is based on. If it is based purely on experience, and that basis is adequate, it will be purely immediately justified. If it is based partly on experience and partly on other beliefs, its justification will be partly immediate and partly mediate.”

His recognizes the mediative role of previously held beliefs in the interpretation of perceptual experience, but does not assert that such background beliefs are required in the formation of perceptual belief. Alston writes:

Background beliefs not infrequently figure in the total basis of perceptual beliefs, and in these cases the justification of the latter depends in part on the justification of the former. Nevertheless this is less common than it seems on first sight, and we can often explain the justificatory relevance of background beliefs without supposing them to be part of the basis, and so part of the prima facie justification. Thus there is considerable scope for purely immediately justified perceptual beliefs, even though partly mediately justified beliefs must also be taken into account.

In applying this formulation to M-beliefs, Alston writes:

If God appears to me as φ (or at least so it seems to me), then that will contribute to justifying a belief that God is φ; if the belief is purely immediately justified, that will be the whole story. If one is aware of what one takes to be God as loving or almighty, then, if no partly doxastic basis is involved or required for justification, a belief that God is loving or almighty formed on that basis is thereby prima facie justified. If one is aware of what one takes to be God as comforting one or saying that P to one, then, with similar restrictions, a belief that God is comforting one or saying that P to one is thereby prima facie justified.

Regarding whether God can be perceived, Alston lays out the summary of his argument as such:

To come to grips with the serious, unconfused problem here, we will have to cut through some unwarranted assumptions that may be behind these questions. We should not suppose that in order to succeed in perceptually recognizing an object of perception as X (i.e., become perceptually justified in believing, or perceptually know, that the object is X), it is necessary that the object appears to one as φ, where φ is a property uniquely possessed by X. To perceptually recognize your house, it is not necessary that the object even display features that are in fact only possessed by your house, much less features that only your house could possess. It is enough that the object present to my experience features that, in this situation or in situations in which I generally find myself, are sufficiently indicative of (are a reliable guide to) the object’s being your house. And so it is here. For me to recognize what I am aware of (X) as God, all that is necessary is that X present to me features that are in fact a reliable indication of their possessor’s being God, at least in situations of the sort in which I typically find myself. It is, again, not required that these features attach only to God, still less that they be such that they can attach only to God. And it is a matter for detailed investigation what sorts of appearances satisfy that condition, just as in the case of sensorily perceived objects.

He then reviews the accounts of spiritual experiences he provided earlier in the book in order to identify the ways in which God presented his qualities as God.

In chapter 3, Alston surprisingly maintains that it is not possible to give adequate reasons for supposing that the beliefs formed by sense perception are reliable, even though it is common practice to do so. In this way, Alston casts doubt upon the entire enterprise of a sense perception basis for accurate epistemology—on both a natural and mystical level. Alston writes,

It is widely believed that we are in a much better position to judge that sense perception is a source of justification than we are in the case of theistic perception. Many even believe that we can show that sense perception is reliable, but not that mystical perception is. These convictions are used as a basis for downgrading the epistemic status of the latter and for denying that beliefs formed on the basis of theistic perception are justified. Looking carefully at attempts to show sense perception to be reliable will put us in a position to assess these views.

Alston demonstrates that arguments attempting to prove the reliability of sense perception fail due to their epistemic circularity. Alston writes, “If we have to assume the reliability of SP [sense perception] in order to suppose ourselves entitled to the premises, how can an argument from those premises, however impeccable its logical credentials, provide support for that proposition?” The simplest version of the argument for the reliability of SP is that it is proven by its fruit. In other words, if our understanding of reality based on SP are most often confirmed through prediction and control of events, then SP is reliable. However, this argument suffers from epistemic circularity in that the only way to confirm the accuracy of the fruit of SP is through the use of SP. Alston reviews a number of arguments for the reliability of SP put forth by (or emerging from) Descartes, Wittgenstein, Oldenquist, Kant, and Locke. However, he finds them all lacking, primarily due to the pitfall of epistemic circularity.

We don’t think Alston’s views and other philosophers’ responses to them will be very exciting or edifying except to readers who are deeply interested in technical debates about epistemology. But we found that they sparked interesting conversations for us about skepticism and how people personally respond to skeptical arguments. They also led us to discuss the conditions under which people can learn from other people’s experiences, and the assumptions that we may need to use in order to assess the evidentiary value for us of other people’s beliefs.

5. Near Death Experiences

For some people, near death experiences (NDEs) are a compelling form of spiritual experience that can be life-altering in its consequences. Those who have them may believe that they have met God, angels, or other spiritual beings, that they have in fact died and then deliberately been sent back to life, or that they have received some kind of teaching or message from spiritual entities. In some cases, they may claim to have received information that would be objectively confirmable by others. Some of those who have such experiences have written popular books recounting them and arguing for specific religious or metaphysical views on the strength of their and others’ experiences.

One major scholarly work on near death experiences is Otherworld Journeys: Accounts of Near-Death Experience in Medieval and Modern Times by Carol Zaleski. Zaleski reviews historical accounts of NDEs, as well as modern ones.

Although their contents and interpretations vary, NDEs are remarkably common in the modern world. Among those who come close to dying, the percentage of those who experience NDEs appears to range from 34 percent to 43 percent.

One reason why NDEs are ripe for research is their commonalities. Zaleski writes, “The [sympathetic] researchers agree that the similarities of near-death reports are more striking than their differences and see this unanimity as a key to the validity of near-death experience.” It has also been observed that NDEs do not always conform to the individual’s pre-existing desires or expectations, thereby contradicting the idea that they are merely comforting fantasies of some sort. Another argument for their validity is their lasting, transformative effects on the individual. Zaleski writes of the striking independent consistency of NDEs:

Age, sex, race, geographic location, education, occupation, religious upbringing, church attendance, prior knowledge of near-death studies, all have negligible effect on the likelihood of near-death visions. Suicide victims seeking annihilation, fundamentalists who expect to see God on the operating table, atheists, agnostics, and carpe diem advocates find equal representation in the ranks of near-death experiencers. And their answers to survey questions show that, for all the religious implications of near-death experience, a person’s beliefs about God, life after death, and heaven and hell do not determine the content of his vision.

One study produced the following statistics: 60 percent described a sense of peace. 37 percent reported feeling a separation from the body. 23 percent entered a darkness. 16 percent saw light. 10 percent entered the light.

There are a number of strong objections to viewing NDEs as experiences of a spiritual reality. Notably, NDEs by definition occur at moments of great damage and stress to the body, commonly in the course of partial or even complete failures of its systems. Thus, one could view NDEs as perceptions that are symptomatic of this damage in some way. One objection characterizes NDEs as hallucinations due to dysfunction in the nervous system. Another objection suggests that sensory deprivation leads to the experience of NDEs. If the brain is continually cut off from the ability to perceive or process external perceptions, it composes its own reality. (Immersion in a sensory deprivation tank, for example, often produces vivid sensory hallucinations.) If the neurological structure and functions of the brain alone are responsible for constructing these NDEs, then this would account for the commonalities of these experiences. Another criticism of the spiritual view of NDEs is the concept that human psychology will always attempt to deny death. “Although contemporary psychological treatments of this subject differ, all rest on the axiom that the mind will resort to any stratagem to push from view the prospect of its own annihilation….”

However, Zaleski states that each individual objection cannot account for every reported NDE: “for every pathological condition presumed to cause near-death visions, one can find subjects who were demonstrably free of its influence….” Zaleski continues: “researchers cite statistics that show an inverse relationship between near-death experience and various pathological mind-altering conditions….” For example, the experience (or recollection) or NDEs seems to be inhibited by the effects of drugs and anesthetics. For this reason, it seems unlikely that drugs are responsible for the generation of NDEs. Zaleski writes, “Backed by the collective testimony of hundreds of subjects, researchers contrast the alert, blissful, lucid quality of near-death experience to the confusion, anxiety, and perceptual distortions that accompany such disorders as hypoxia, limbic lobe syndrome, autoscopy, depression, and schizophrenic hallucination.”

While it seems the critics’ of individual suggestions for biochemical or psychological explanations of the origins of NDEs are dispatched by the variety of cases which do not conform to such explanations, if these criticisms are seen as a whole, then perhaps all NDE cases can be explained only by materialistic means. Zaleski writes: “any feature of near-death experience that is not finished off by endorphins can be dispatched by temporal lobe seizure, depersonalization, state-dependent birth recall, and so forth.”

However, there are still arguments against this unified front. Firstly, if there were a number of underlying causes for NDEs, why is their nature so consistent? In other words, wouldn’t different biochemical processes produce different kinds of experiences? If consistency is a striking component of NDEs, it seems unlikely that there would be a lack of consistency in their origins. Secondly, Zaleski warns against a reductionistic view of NDEs when such heavy reductionism is not (usually) applied to general human experience. She writes,

After all, not only extraordinary visions but also normal states of consciousness are linked with electrical and chemical events in the brain, hormonal tides in the body, inherited drives, and cultural coercion. Yet we do not apply reductionist vetoes to our ordinary experience. Love can be explained in terms of neurochemical and social mechanisms, ranging from the influence of advertising to the lure of pheromones; but scarcely anyone suggests that knowledge of these mechanisms should prohibit people from believing that they are in love and rearranging their lives accordingly.

Why should an NDE be dismissed as invalid or hallucinatory because we are able to point to associated neurological or biochemical processes? It may be important to interrogate the reasons why we may be inclined to discount the subjective experiences of NDEs even if naturalistic processes are at play. (The same sort of question will arise again when we ponder experiences with psychoactive substances.)

Zaleski herself advocates for a balance in understanding and appreciating the symbolic and narrative value of NDEs while being skeptical of their theological value. She writes,

Clearly, a new approach is needed; to make near-death testimony an arena for restaging old philosophical or theological battles will not suffice. It appears to be impossible, in any case, to determine objectively whether near-death reports are accurate or inaccurate depictions of the future life. It might therefore be more fruitful for theologians to consider near-death visions as works of the religious imagination, whose function is to communicate meaning through symbolic forms rather than to copy external facts. This is the aspect of near-death literature that I have attempted to highlight.

In other words, Zaleski does not personally believe that NDEs point to an objective spiritual reality, but that they should nevertheless be afforded personal and cultural significance. She writes,

I suggest, therefore, that a pragmatic method and a sensitivity to symbol must go hand in hand if we wish to give a fair hearing to the claims of near-death literature. If we fully recognize the symbolic nature of near-death testimony (and accept the limits that imposes on us), then in the end we will be able to accord it a value and a validity that would not otherwise be possible; this in turn will yield further insight into the visionary, imaginative, and therapeutic aspects of religious thought in general.

Zaleski seems to take a position which stands in weak support of the controversial statement at the core of this paper. Although she does not see NDEs as pointing to any sort of genuine mystical reality, she nevertheless sees value in such experiences. If Zaleski is right, and NDEs merely carry symbolic power, they would still be representative of an important component of human life as a kind of spiritual experience with powerful, lasting effects upon the individual.

6. The Use of Entheogens

Perhaps the relevant topic which is most suited toward empirical study is the use of entheogens in the generation of spiritual experience. This seems true for a few reasons: firstly, they are drugs whose chemical make-up can be scientifically studied and described, and secondly, their effect on the human on the biochemical and neurochemical levels can also be scientifically studied and described. We also have the benefit of several decades of scientific research on these substances, in addition to extensive reports from people’s self-experimentation, and anthropological and insider accounts of their use within traditional religions. A number of psychedelic substances have also recently benefited from a new round of legally-sanctioned medical investigations aimed in part at evaluating their potential use in psychiatry.

Entheogens are psychedelic drugs or other preparations of comparable substances that tend to produce a subjective experience of a divine or spiritual nature. They are controversial on many levels; most are legally controlled substances, they are often seen by governments and health authorities as having the potential to be abused, and different religious traditions have radically opposed views about their harms and benefits. It is also striking that they seem to offer such a reliable way to create experiences that most subjects view as meaningful and spiritual, although the content of these experiences and the way participants account for them varies tremendously.

Writing for The Outline about her personal experience with psilocybin in a controlled setting at Johns Hopkins, Rachael Peterson states:

Like all trip stories, mine sound crazy at worst and clichéd at best. But I can tell you this much: at the peak of my experience, my sense of self dissolved and I unified with an abiding force that permeated all existence — something that felt conscious, vast, benevolent, eternal, peaceful, and furiously important. After sitting up on the couch six hours later, covered in snot and tears, I struggled to put words to an encounter that felt more real than everyday reality — a mind-bendy paradox characteristic of many mystical experiences.

Similar accounts (often involving interaction with entities that seem conscious and intelligent) are described repeatedly in case reports by DMT researchers such as Rick Strassman.

A recent paper analyzes the data of five groups who had experiences with various entheogens, including psilocybin, LSD, ayahuasca, or DMT, as well as one who had spiritual experiences without the use of drugs. The authors of the paper note that there are some differences between the experiences of the entheogen cohort and the non-drug cohort, they are more similar than different. The most striking finding was that two-thirds of participants who identified as atheist prior to their experience no longer considered themselves atheist afterward. The abstract of this article summarizes the nature of these experiences:

Most participants reported vivid memories of the encounter experience, which frequently involved communication with something having the attributes of being conscious, benevolent, intelligent, sacred, eternal, and all-knowing. The encounter experience fulfilled a priori criteria for being a complete mystical experience in approximately half of the participants. More than two thirds of those who identified as atheist before the experience no longer identified as atheist afterwards. These experiences were rated as among the most personally meaningful and spiritually significant lifetime experiences, with moderate to strong persisting positive changes in life satisfaction, purpose, and meaning attributed to these experiences. Among the four groups of psychedelic users, the psilocybin and LSD groups were most similar and the ayahuasca group tended to have the highest rates of endorsing positive features and enduring consequences of the experience. Future exploration of predisposing factors and phenomenological and neural correlates of such experiences may provide new insights into religious and spiritual beliefs that have been integral to shaping human culture since time immemorial.

Certainly the subjective power of these experiences cannot be denied, as their transformative effects upon the subjects’ personal lives can attest. In the conclusion, the authors reiterate that that the reported effects of these experiences led to “persisting moderate to strong positive changes in attitudes about self, life satisfaction, life purpose, and life meaning that participants attributed to these experiences.” Legal obstacles have meant that formal therapeutic exploration of many entheogens is just beginning, but it seems apparent that they have promise in treating mental illnesses through catalyzing deep experiences of profound meaning.

Good Friday Experiment

On Good Friday in 1962, a researcher (Walter Pahnke) administered psilocybin to divinity student volunteers just before they attended a Christian worship service. The results were dramatic; almost all of the research subjects reported profound experiences which they continued to regard as meaningful and important for the rest of their lives (as confirmed by a follow-up survey decades later). Some have described the experience as the most powerful spiritual experience of their lives—which is noteworthy because they were generally already religious believers who were preparing for careers related to their Christian faith. The volunteers clearly understood that they were being given a drug, which did not seem to reduce their assessment of the spiritual importance of their experience at the time or upon subsequent reflection.

Huston Smith, a scholar of comparative religion, was one of the participants in the experiment and describes his experiences in Cleansing the Doors of Perception, his survey work on entheogens. He says that his attention was fixed on particular melodic and lyrical features of a hymn sung during the service, and his musical training and Christian upbringing

converged on the Good Friday story under psilocybin, [and] the gestalt transformed a routine musical progression into the most powerful cosmic homecoming I have ever experienced.

In an interview he reprints in the same book, Smith remarks that the experiment

[…] enlarged my understanding of God by affording me the only powerful experience I have had of his personal nature. I had known and firmly believed that God is love and that none of love’s nuances could be absent from his infinite nature; but that God loves me, and I him, in the concrete way that human beings love individuals, each most wanting from the other what the other most wants to give and with everything that might distract from that holy relationship excluded from view—that relation with God I had never before had. It’s the theistic mode that doesn’t come naturally to me, but I have to say for it that its carryover topped those of my other entheogenic epiphanies. […]

Sam Harris cautions in Waking Up that if powerful and important spiritual experiences can be produced by a particular context, we should be wary of taking them as evidence for specific doctrinal metaphysical claims, since presumably these experiences can be, and are, encountered within many different religious traditions. If Christian divinity students had an experience that they took to be an encounter with God under the influence of psilocybin at a Good Friday service, other subjects might experience equally compelling encounters that they interpreted when using the same subject in another setting, or merely with different prior metaphysical beliefs. Harris supposes that a spiritual experience he personally had at the Sea of Galilee would have confirmed for him his particular religious faith, if he had had one. Later Harris asks:

What does a spiritual experience mean? If you are a Christian sitting in church, it might mean that Jesus Christ survived his death and has taken a personal interest in the fate of your soul. If you are Hindu praying to Shiva, you will have a very different story to tell. Altered states of consciousness are empirical facts, and human beings experience them under a wide range of conditions.

Smith is also sensitive to this reasoning and notes that participants in other religions’ rituals, and those raised in different traditions, have had equally powerful experiences of their own. But Smith and Harris take this observation in radically different directions; for Harris this diversity undermines any specific metaphysical claim that any religious tradition might advance, while for Smith, it provides an encouragement to try to find commonalities in different religious experiences and reason to suspect that they are pointing toward the same reality.

The Eleusinian Mysteries

[…] χαλεποὶ δὲ θεοὶ θνητοῖσιν ὁρᾶσθαι.

[…] gods are hard for mortals to recognize.

— Homeric Hymn to Demeter, 111 (translated by Helene P. Foley)

The Eleusinian Mysteries were an ancient Greek tradition practiced for thousands of years relating to the worship of the goddess Demeter and the story of her daughter Persephone’s descent into and return from the underworld. (The story, itself widely known in Greek culture, said that Persephone was kidnapped as a bride by Hades, the god of the underworld, and yet Demeter was able to bring her back—at least for part of each year, corresponding to the growing season.)

The associated ceremonies could at least originally be practiced only at a specific site near the city of Eleusis. Participants signed up to be initiated over the course of several days, during which they participated in allegorical rites. The initiates swore a vow of secrecy and were never allowed to talk about the details of what the rites consisted of. Although participants went home afterward and returned to their normal lives, virtually all of them took the vow extremely seriously, taking their memories to their graves, so we know very little today about exactly what went on at Eleusis.

The Mysteries attracted participation from the rich and famous of the classical world, and remained extremely popular throughout classical antiquity. (They were open to the public, but could only be experienced, or discussed, in the proper place, at the proper time, with the proper preparation.) Although those who had taken part almost never gave any concrete details, they generally considered the experience extraordinarily valuable and worthwhile, and often recommended it in the strongest terms to their friends and family members. Many indicated that they had had some kind of contact with the divinity during the initiation, and some said that they were no longer frightened of death. Many sources suggest that the Mysteries taught, or showed, their initiates some very specific reason why death was nothing to be afraid of—and participants apparently took this lesson to heart. Cicero, who was probably a participant himself, says in his De Legibus that the Mysteries’ initiations allowed “neque solum cum laetitia vivendi rationem accepimus, sed etiam cum spe meliore moriendi” (“[that] we not only took from them a way of living happily, but also a way of dying with a better hope”).

The Mysteries stopped being celebrated with the rise of Christianity and no one has experienced them at all for more than a millennium and a half. Since then, people have remained intensely curious about what was done and taught in these ceremonies, and why participants found them so valuable and transformative, over and over again, and why so many of them claimed to lose all concern about death. How could this have happened? Were all of them really encountering Demeter, or witnessing Persephone returning from the realm of the dead?

One interesting fact is that all the initiates were given a drink called a kykeon (κυκεών, meaning something like ‘mixture’) during the course of the initiation. The recipe for the kykeon is one of the details lost to history due to the Mystery initiates’ dedication to keeping their vows, but people have often wondered about how it might have affected those who drank it. In the 1960s, two prominent psychedelic researchers (R. Gordon Wasson, who introduced psilocybin to the American public, and Albert Hofmann, who discovered LSD) and a classicist (Carl Ruck) published The Road to Eleusis, a book arguing that the kykeon contained substances derived from the ergot fungus. Wasson and Ruck subsequently published numerous other books arguing that religions all around the world have traditionally used psychoactive substances (termed entheogens) to facilitate the experience of the divine, and that religious doctrines, narratives, and rituals are often at least initially based on drug-mediated experiences. Other scholars have tended to accept the view that the kykeon probably contained psychoactive substances, even if they disagree about exactly what substances these were.

Interestingly, scholars who endorse a substance-related explanation for the experiences of Eleusinian initiates (and for the origins of other religious traditions and narratives) don’t necessarily believe that they are debunking or explaining away these experiences. This is an oddity for skeptics who might imagine that initiates were being tricked into interpreting their experiences as divine contacts or visions.

7. The Problem of Dreaming

Dreaming is a universal human experience that poses a difficulty for confidently viewing spiritual experience as veridical, because dreams usually feel so real and feel so important. They represent a familiar, ubiquitous form of experience that is



Vividly perceived

Often deeply personally meaningful

Often considered, at least metaphorically, to reflect the experiencer’s deepest desires, aspirations, or values

Sometimes transformative in their consequences

Usually accepted as completely real during the experience itself

Often involve extended interactions with other beings who are perceived as separate from the experiencer Difficult to convey to others

Yet modern western culture mostly accepts that dreams are not veridical—that they tell us little or nothing about how the world is—and that at most they might reveal or reinforce something about the dreamer’s own memories, desires, or unconscious psychology. (It’s worth noting that many cultures have assumed, or believed on evidence, that dreams do come from somewhere outside us, or that they represent a visit of some kind to another world. Many people have routinely believed, or routinely believe, that dreams represent genuine visions of the future, visits from one’s ancestors, temptations from evil forces, or glimpses of the real structure underlying the mundane world. Our neuropsychological depiction of dreaming as the brain’s efforts to make sense of random noise is quite unusual among cultures’ ways of accounting for dreams. But all cultures have had to deal with the ephemerality of dreams and the way that their content is at best unreliable and difficult to make practical use of in one’s day-to-day life.)

The relevance of dreams for a skeptical account of spiritual experience could include a strong version and a weaker version. In the strong version, many spiritual experiences could be suspected of originating in dreams that had been somehow misperceived or misremembered by their dreamers as waking experiences, or correctly perceived as dreams but somehow nevertheless accepted as genuine. In the weaker version, dreams simply provide an analogy that shows that our minds are sometimes capable of producing experiences that feel genuine and important, whose genuineness we reflectively accept, but whose connection to mind-independent reality is questionable.

A counterargument is that we should not have to doubt all of our interpretations of our experiences merely because we are sometimes temporarily mistaken about whether we are dreaming. Otherwise, we would fall into radical skepticism about all of our knowledge and experience. (People throughout history have flirted with embracing this conclusion seriously in various ways. For example, Descartes uses the experience of waking from a dream that he had believed in while it lasted as a touchstone of his motivation for undertaking to doubt everything, the Chinese philosopher Zhuang Zhou claims not to know “whether he was a man who dreamt he was a butterfly or a butterfly dreaming he was a man”, while the movie Inception depicts people who, accustomed to the experience of “awakening” within a dream, become unsure of how many times they still have to wake up in order to return to the waking reality.

What kinds of things could affect our judgment about whether particular dreams, or some dreams, are veridical? Perhaps dreams could be shown to foretell future events. Or perhaps the content of many people’s dreams could coincide, like Italo Calvino imagines in Invisible Cities:

They tell this tale of its foundation: men of various nations had an identical dream. They saw a woman running at night through an unknown city; she was seen from behind, with long hair, and she was naked. They dreamed of pursuing her. As they twisted and turned, each of them lost her. After the dream, they set out in search of that city; they never found it, but they found one another; they decided to build a city like the one in the dream.

But sometimes the content of different people’s dreams does coincide. For example, many people have a recurring dream that they’re in school and have somehow skipped class or forgotten to prepare for an important test. Why do so many people share this dream content? Does this suggest that there’s something veridical about this particular dream? Or at least that there’s something psychologically important about this situation?

Certainly the communication of dreams and their subjective significance mirrors the difficulties encountered by someone who wishes to communicate a spiritual experience. Dreams are usually deemed significant only to the one who has the dream. Most of us find that to be completely appropriate. However, spiritual experiences are generally thought (at least by those who have them) to be important enough to share with others, potentially as experiences of something real and relevant for others. The question then is how we might differentiate between a dream and a spiritual experience for the skeptic. Research into spiritual experience tells us that the two are different, at least in how they are perceived by the individual. It is often the case that dreams are easily forgotten and cease to seem real when the dream is over. However, spiritual experiences—particularly those of the NDE and entheogenic varieties—have lasting effects, and, at times, permanently changing behavior. As Zaleski writes about near death experiences: “In addition, against Siegel’s sweeping comparison of near-death visions to the psychoneurology of hallucination, the researchers cite nearly unanimous testimony that near-death experience is subjectively different from dreaming or intoxication; that it is, as one of Sabom’s subjects puts it, ‘realer than here.’” This may be true for the one who experienced the NDE, but, for those who did not have that experience, hearing about it may elicit a similar reaction to hearing about a dream.

8. Some Possible Perspectives

We join in recommending epistemic humility across the board for all perspectives. To have any sort of meaningful discussion about any topic, we must allow for the possibility that we are possibly wrong in our opinions and beliefs. Dialogue about experiences that bear on people’s religious (or anti-religious) beliefs is often challenging.

We should be careful in how we interpret spiritual experience, especially if it prompts us to take action or change behavior. If a metaphysical or spiritual reality does not exist, then this suggestion is self-explanatory. However, epistemic humility is still important if a metaphysical or spiritual reality does exist. Suppose that God can and does speak to humans. The present evidence supports the idea that such communication may not always be clearly understood or interpreted by the human listener, and that human beings may not find it easy to be confident about when God is speaking to them. If this were not true, we would obviously not see such a broad range of (often) conflicting divine messages. Being careful with the knowledge and action generated by spiritual experience is therefore wise.

In a related context, we had fruitful discussions of the parable of the blind men and the elephant. The blind men and the elephant is an ancient story, and we highly recommend the Wikipedia entry for it. The basic story is that a number of blind men came upon an elephant, and they all touched the elephant while attempting to describe it. They all disagreed upon the nature of the elephant because one man felt the side of the elephant and said it was like a wall, while another felt the trunk and said it was like a snake, etc. Interestingly, the moral that this story is meant to convey is subject to dispute by its listeners! One might take the lesson of the story as a metaphor, for each blind man erroneously believes in the truth of his own religious doctrines based his limited perception. Because each person’s perception is limited, conclusions on the nature of the elephant cannot be trusted. However, another way to interpret the story begins with the idea that the radical differences of perception should not be taken as proof that there is no elephant. People in different cultures and time periods may be seeing something real, but their description of it may not be complete. The lesson may be that even though we are tempted to discount spiritual accounts because of their inconsistency, we should not discount them completely because they may still be of evidential value, albeit in a more limited or complicated way than the authors of the accounts appreciate.

Like Plato’s allegory of the cave and other thought experiments in philosophy, the tale of the blind men and the elephant reminds us that epistemology is hard. It’s also challenging to integrate reported perceptions and experiences that differ greatly from person to person. Much of our reason for confidence in our understanding of the physical world is our ready and far-reaching intersubjective agreement about our sense perceptions of it. “Everyone” more or less agrees that we see the Moon in the sky, hear the sounds of rain, are injured by fire, like the taste of sugar, or find it challenging to lift horses. Accepting these widely-shared perceptions as veridical even without discussion or reflection is the most natural thing in the world. But when Blake says

I assert for My self that I do not behold the Outward Creation & that to me it is hindrance & not Action; it is as the Dirt upon my feet, No part of Me. “What,” it will be Questioned, “When the Sun rises, do you not see a round Disk of fire somewhat like a Guinea?” O no no, I see an Innumerable company of the Heavenly host crying “Holy Holy Holy is the Lord God Almighty.” I question not my Corporeal or Vegetative Eye any more than I would Question a Window concerning a Sight: I look thro it & not with it.

it may be a greater challenge to achieve a consensus about the status of his vision, even if we suppose that he reported it faithfully and earnestly.

As we mentioned, Alston’s work prompted us to discuss some epistemological issues. We recognized the likelihood that people’s intuitions will vary as to what evidence is compelling enough to consider a spiritual experience to be (some combination of) true, authentic, and/or indicative of some spiritual dimension of existence. (Even some of the authors we read are still struggling with this question for themselves.)

Apart from this, we might ponder the notion that entheogenic or meditation experiences are valuable because they bring people in contact with facets of their own consciousness that are not normally accessible, whether or not we believe that these facets are metaphysically different from ordinary experience of the world and the mind. Some advocates of meditation and/or entheogens who incline toward naturalism maintain that we are “merely” learning more about ourselves (or, perhaps, our non-selves) through these experiences, yet that this learning is of immense value. Clearly, entheogens generate experiences which have lasting, powerful effects upon those who take them, and which are often described as improvements in their users’ lives. Even if it is not a revealing of a separate spiritual reality, should such striking and consequential entheogenic experiences be considered “real” at least in terms of the individual’s own psychology? Considering the literature on the psychological study of religious experience, on near death experiences, and on entheogens, it is undeniable that people subjectively experience genuine states of being which transcend normal states of consciousness. Is there a satisfactory way to consider these experiences’ meaning without insisting that they prove something specific about how the world is? And, considering Alston, is it even plausible to expect more than this from any particular kind of human perception?

Alston might maintain that two people may be justified to believe different things based on differing experiences. Their perspectives may be in conflict, but this need not imply that either is behaving irrationally. It may be rational for one person to believe that spiritual experiences are indicative of a spiritual plane of existence that is usually inaccessible, while another person may also be rational in the belief that such an idea is silly nonsense and that spiritual experiences are the result of purely natural causes. Alston’s concept of epistemology is that it is empirically formed through perceptual experience. Therefore, rational knowledge may not ever be universally uniform. In fact, this prospect is widely accepted in rationalist and empiricist circles, since rationality has to do with making good use of evidence and different people are in possession of different evidence. Those with spiritual experiences simply have a particular sort of evidence which they may try to interpret alongside other forms of evidence.

Regarding veridicality and consensus, one possible tool in the difficult arena of parsing spiritual experience is inquiry for confirmation. People generally agree upon the common physical and psychological experiences of natural life (e.g. “we both agree this coffee is too hot to drink right now,” or “everyone is laughing so this movie must be funny”) while also finding dissimilarities (e.g. “although this coffee is too hot for you to drink, and I agree that it is hot, it is not too hot for me to drink,” or “everyone else is laughing, but I don’t think this movie is funny”). This kind of discussion of experience toward confirmation is actually rather common in everyday life. Spiritual experience might be discussed and confirmed in a similar manner, leading to increased confidence in confirmed commonalities compared to experiences that do not seem to be shared. These discussions could, of course, be extremely culturally or institutionally difficult. In light of Alston’s claims about the general unreliability of all human perception, finding where subjective experiences agree (whether spiritual or otherwise) is a wise course of action. Of course it is still possible to find agreement and still be wrong, but at least we’ll be wrong together.

One reason why empiricism seems to be of value in discussing and interpreting spiritual experience is that people’s experiences tend to steer both our beliefs and our skepticism. Skepticism is a powerful tool that can be leveled at anything. As a negative example, conspiracy theorists can find reasons to be skeptical of any claim which rebuts their conspiracy theories. More relevant to this project, one could criticise both religion and materialistic rationalism as being culturally conditioned and psychologically motivated phenomena. Skepticism can cut both ways on this topic. However, understanding that our experience informs our future views, then even amidst our own skepticism of spiritual experience, we can appreciate the potential rationality of various worldviews informed by such experiences.

Concluding Thoughts

The question that we’ve aspired to consider in this project is:

The empirical study of the content and nature of people’s personal spiritual experiences justifies taking them seriously as evidence of an important component of human life deserving of individual and collective exploration.

What are the present authors’ views of this statement, and what did they learn that surprised them?

Gruenberg originally proposed the project from the point of view of a supporter of this statement; at the end of the project, he finds that he strongly agrees with it.

Gruenberg found a number of surprises in the course of this research. The first is the vast amount of empirical research that has already been accomplished, particularly in the field of psychology. The researchers in the field are serious about the objective study of spiritual and religious experience, regardless of their stance on their veridicality. Their commitment to objectivity and sensitivity to the subject is admirable. The second is the compatibility of the (often) secular use of entheogens with non-drug-assisted spiritual experience, particularly in the emotional benefits of entheogenic experiences, as well as the surprising conversion rate of atheists to non-atheists through the use of entheogens. The third is Schoen’s objection to the veridicality of spiritual experience on the grounds of the non-veridical nature of dreams. Mystical experiences of waking life—including meditative transcendent states of the loss of self and numinal encounters with God—seem to be of a different nature than dreams, but their precise differences are difficult to articulate to those who have not had them. The fourth is the all-encompassing nature of skepticism that we could have regarding any sense perception (advocated by Alston) that ends up “leveling the playing field” between spiritual and non-spiritual experiences mediated by our perception. In other words, if all sense perception is suspect, then spiritual experiences are no less suspect than material experiences. The fifth is Schoen’s use of the parable of the blind men and the elephant in order to demonstrate the possibility that limited perception may not always be erroneous. Perhaps we are all blind men and women, probing the elephant of reality. If we live in a version of that parable, then it is even more imperative that we actively seek a discourse which explores our disagreements with a willingness to try on some different versions of the elephant.

Schoen joined the project as a skeptic of this statement, but concludes that he ends in weak agreement with it, noting that a broad spectrum of authors whose work we considered maintain that the human mind is capable of a much broader range of experiences than we’re used to thinking of, and that these experiences can potentially be sought out deliberately and often have profound consequences for the experiencers’ lives and worldviews. In some sense, this much is agreed by people with otherwise opposing views on questions such as naturalism or theism. These authors maintain that there is more inside us than we know, or that we are capable of more than we know, or that personal experiences can give rise to important philosophical challenges. While it’s not clear that these facts imply any particular view of reality or the universe, they seem to have import, at least, for our own lives and self-concepts.

Schoen was also surprised by a number of things he learned in the course of this research. The first is the way that large numbers of people do not dismiss the meaning or relevance of their own or others’ drug-mediated experiences even when they are explicitly aware that they were “on drugs” and that their normal brain function was altered by the influence of substances like LSD, psilocybin, mescaline, or DMT. Reminding them of the drugs’ role does not seem to change this. What’s more, vast numbers of people durably rate these experiences as extraordinarily significant, valuable, and influential, even on sober retrospective reflection, and tend to feel that their understanding of their minds was expanded. Schoen would have expected the role and impact of substances in religious ritual from antiquity to the present as a sort of dirty secret that would draw the meaning or authenticity of religious experience into question. Instead, many participants in religious practices have demonstrated that they knew that drugs were centrally involved and did not reject the experiences or associated insights on that account.

A second surprise is the analogy drawn by Alston and others between the unreliability of spiritual perception and the unreliability of other sorts of perception, including some that clearly are part of our social consensus about reality. One can note that sense perceptions like vision and hearing are well-confirmed by the understanding they yield of the physical world and the predictions this understanding allows us to make, but other kinds of perceptions are socially normalized and believed even without the same degree of objective confirmation. While Alston might have an extremely low prior for the plausibility of metaphysical naturalism, and even shockingly low from the point of view of the median SSC reader, it’s interesting to consider the idea that perceptions other than the use of our bodily senses can rationally count as evidence much like other evidence. (This debate really starts there rather than ending there, and includes rather involved issues about how our beliefs and experiences reinforce one another.) It’s interesting to note how cultural and societal consensus hold so much more power over belief (in all different eras and all different sorts of societies) than any kind of formally-reasoned epistemology according to a detailed philosophical theory!

A third surprise is the extent to which mystical traditions are consciously aware of the risk of spurious spiritual insights due to, for example, mental illness. Skeptics often suggest that neurological disorders such as epilepsy might cause experiences that religious believers interpret as religious ecstasy or revelation. Organized religious and contemplative traditions are at least grappling with these risks and actively trying to find ways to distinguish experiences that they see as valuable from experiences that might be attributed to disorders. Mark Salzman’s novel Lying Awake movingly described this issue as it presents itself in the life of a nun who receives a sense of purpose and fulfillment (and more practical benefits for herself and her religious community) from ecstatic religious visions that are later attributed to the influence of a treatable brain tumor. All traditions and communities that rely on visions and revelations worry about how one can tell whether a particular experience constitutes a good or legitimate source of insight or teaching, although their answers are not necessarily satisfactory or reassuring to outsiders.

A fourth surprise is the frequency with which spiritual experiences are more often sought out or provoked rather than spontaneous or unexpected, and the popularity of the view that one can be taught to have such an experience by a particular method (particularly in contemplative and mystical traditions, as well as among advocates of insight meditation and entheogens). Near-death experiences are a major exception here because people have rarely actively hoped to receive one or sought one out. Quite a few traditions suggest that there is a specific thing we ought to do, or a specific practice we ought to follow, in order to receive spiritual experiences and spiritual insights. While that creates its own set of risks (for example, of being manipulated or exploited by an unscrupulous teacher or dysfunctional community), it also provides an interesting opportunity for people to try things out for themselves if they’re so inclined. This picture of practical steps is especially associated with secular Western interpretations of Buddhism, which emphasize the claim that Buddhist teachings can be taken as a phenomenological how-to guide.

This collaboration expressly excluded the truth or falsity of naturalism, or of any specific religious doctrine, from its scope. Although we and many of the authors we consulted have views about this, we didn’t try to find a consensus about these questions. The evidence for and against a naturalistic worldview, or for and against some specific kind of supernatural phenomenon, might make an interesting adversarial collaboration topic for others in the future.

It’s worth acknowledging the pervasiveness of the belief that spiritual experiences can’t usefully be described or analyzed in words, and that trying to theorize about them is an absurd and useless activity. On this account, this whole project is an exercise in futility, doomed from the start, and perhaps a mockery of itself. While the present authors don’t share this attitude, and even see it as counterproductive, they realize that others would strongly recommend experiencing spirituality, not talking about it.

We realize that there is a huge literature about the phenomenology and interpretation of spiritual experiences, and that we’ve only managed to scratch the surface here. Nor have we engaged with every issue raised within the sources that we did review. Interested readers looking for more material on these topics might want to start with Prof. Wesley Wildman’s bibliography on religious experience at <http://people.bu.edu/wwildman/relexp/bibliographies/bib_general.htm> or the Stanford Encyclopedia of Philosophy’s article on religious experience at <https://plato.stanford.edu/entries/religious-experience/>.

About the Authors

Jeremiah Gruenberg has a Ph.D. in theology. He writes and hosts a podcast on Christian spirituality, called The God Experiment.

Seth David Schoen is a computer and language enthusiast living in San Francisco.