A good cultural evolution theory of shamanism would be a welcome contribution to the literature, but the target article errs in core concepts and misrepresents the cited literature. We find other issues problematic (e.g., the disregard of the potential practical benefits of shamanism; see Kleinman Reference Kleinman1980), but will concentrate on clarifying the alterations of consciousness related to shamanism. Singh defines shamans by their manifestation of trance, but misrepresents how the concept is used in the literature. Section 4.2 (Trance Is a Drama of Strangeness) implies that trance is produced by a number of techniques, including starvation, meditation, and relaxation that produce “different physiological and psychological effects” and cites an article by Vaitl et al. (Reference Vaitl, Birbaumer, Gruzelier, Jamieson, Kotchoubey, Kübler, Lehmann, Miltner, Ott, Pütz, Sammer, Strauch, Strehl, Wackermann and Weiss2005). That article, which reviews the literature on 20 different alterations and inducing techniques, only refers to trance as one of them, characterized by narrowing of awareness, select focus, stereotyped behaviors, and lack of control brought about by repetitive drumming (Vaitl et al. Reference Vaitl, Birbaumer, Gruzelier, Jamieson, Kotchoubey, Kübler, Lehmann, Miltner, Ott, Pütz, Sammer, Strauch, Strehl, Wackermann and Weiss2005, p. 107). Even worse, Singh (sect. 4.2) equates trance and ecstasy, referring to Rouget's (Reference Rouget1985) work, but Rouget specifically differentiated them. “Ecstasy and trance may therefore be characterized in relation to one another by a series of terms: Ecstasy (immobility, silence, solitude, no crisis, sensory deprivation, recollection, hallucinations); Trance (movement, noise, in company, crisis, sensory overstimulation, amnesia, no hallucinations)” (Rouget Reference Rouget1985, pp. 10–11; see also Cardeña 1992). Rouget considers them opposite poles of a continuum.

For Eliade (Reference Eliade1964), only what Rouget refers to as ecstasy (etymologically referring to being outside of the body, and which may involve the use of hallucinogens) counts as shamanism. Its prototype includes a soul journey or magical flight in which the shaman leaves the physical body (which is mostly immobile or engages in repetitive movements) to experientially travel, sometimes imitating or “transforming” into an animal such as an eagle, to another realm in which he or she may interact with other beings (Balzer Reference Balzer1996). Eliade thought that mediumship/possession (similar to Rouget's “trance”), involving the experience of becoming a vessel for a preternatural entity, is a later, “degenerate” version of shamanism. Empirical support for Eliade's conclusion of possession as a later cultural development was provided by both Bourguignon's (Reference Bourguignon1976) and Winkelman's (Reference Winkelman1992) analyses, which place classical shamanism (or ecstasy) within hunting/gathering societies, and mediumship/possession within more sedentary, hierarchical societies.

Walsh (Reference Walsh1990) stated that only ecstatic experiences imply mastery of the spiritual (or altered consciousness) realm, but mediumship/possession can become a controlled manifestation in which practitioners choose when and how to become possessed (e.g., Cardeña Reference Cardeña, Quekelbherge and Eigner1996). Hence, we endorse a definition of shamanism that includes both magical flight and mediumship/possession involving: (1) expertise in altering one's (and sometimes others') consciousness, or, in more emic terms, mediating between sacred and profane realms; (2) the ability to fulfill the needs of the community; and (3) social recognition (Heinze Reference Heinze1991; Krippner Reference Krippner2002). We are skeptical that the same cultural evolution processes can explain varying phenomena across different social organizations. To give but one example, a discussion of professionalization is likely to be more pertinent to the socially stratified milieu of mediumship/possession than of classical shamanism. Furthermore, we cannot think of a scholar who uses as broad a definition of shamanic practices and experiences as Singh does.

An important question is why ecstasy and trance have appeared throughout history and around the globe. An explanation with empirical grounding is that they refer to states that people tend to experience, whether in a Brazilian rainforest or in a secular laboratory setting. Research on the phenomenology of highly hypnotizable people has found that they tend to fall into two types: one more characterized by inward attention and vivid imagery or fantasy (more like ecstasy), and the other by a sense of low control and lack of remembrance (more like trance) (Barber Reference Barber, Kirsch, Capafons, Cardeña–Buelna and Amigo1999; Cardeña Reference Cardeña, Quekelbherge and Eigner1996/2005; Pekala & Forbes Reference Pekala and Forbes1997; Terhune & Cardeña Reference Terhune and Cardeña2010; Terhune et al. Reference Terhune, Cardeña and Lindgren2011). These are approximate parallels, of course, and there are also differences. For instance, although some highly hypnotizables may spontaneously experience floating or flying out of the body (similar to a “magical flight”) in hypnosis, they lack a cultural framework to interpret such experiences as referring to other realms of existence (Cardeña Reference Cardeña, Quekelbherge and Eigner1996; Cardeña & Krippner Reference Cardeña, Krippner, Lynn, Rhue and Kirsch2010).

This brings us to another point that is confusingly discussed in the target article. According to Singh, shamans usually go through initiation rituals to become members of guilds that regulate practice. Although this may occur sometimes, we have found far more evidence in our field observations and the literature that initiation and training provide an ethnoepistemology to make sense of unusual experiences and techniques to bring them under control, as the potential shaman might have suffered previously disorganized, uncontrolled, and dysfunctional episodes (Cardeña & Shaffer Reference Cardeña and Schaffler2017; Halifax Reference Halifax1979). Thus, it is not that any strange experience or oddity is exploited by people wanting to be shamans (some individuals resist the call to become a shaman), but that they have unusual experiences and seek to bring them under control for their and others' benefit. Contra the target article, it is not uncommon to find that the manifestations of some traditional healers become less dramatic and strange as they develop mastery (e.g., Cardeña Reference Cardeña and Heinze1991).

Singh also makes other questionable statements. He mentions “the substitution of mystical explanations with naturalistic ones,” apparently counterposing what he takes to be irrational with rational explanations. In reality, a number of eminent scientists throughout history (Einstein, Kepler, Newton, Oppenheimer, Planck, and Schrödinger, among others) have integrated a mystical perspective with logic and science (Bakan Reference Bakan1969; Russell 1917/Reference Russell1970). (The term mystical refers to a sense of interconnectedness reality, not irrationality or anti-naturalism [Wulff Reference Wulff, Cardeña, Lynn and Krippner2014].) He also criticizes that phenomena such as out-of-body experiences can be experienced by “Westerners … familiar with scientific epistemologies” even though having anomalous experiences does not imply irrationality or psychopathology, can be experienced by anyone with that propensity, and can be studied using the scientific method (Cardeña et al. Reference Cardeña, Lynn and Krippner2014). A theory of shamanism needs to have a clear understanding of its explanandum and review the evidence carefully.