‘Philosophy of Psychedelics’ Book Forum: Part One

Nathan Emmerich and Bryce Humphries review Philosophy of Psychedelics (Oxford University Press, 2021) by Chris Letheby.

This is Part One of a Book Forum on Philosophy of Psychedelics. The Forum consists of four reviews and a reflection from the author. 

For Part Two by Evgenia Fotiou, click here.

For Part Three by Nicolas Langlitz, click here.

For Part Four by Sandeep Nayak, click here.

For Part Five by Chris Letheby, click here.

In her 2020 book Acid Revival, sociologist Danielle Giffort makes clear the cultural duality of the ‘psychedelic renaissance’, the term given to the recent resurgence of interest in and research on psychedelics since the early 2000s. On the one hand there are the ‘psychonauts’ who embrace psychedelic drugs as chemicals that can open the ‘doors of perception’ and lead to a range of experiences and realisations that are beyond what is ordinarily possible for human beings. On the other hand, there are the serious scientists, those who recognise the potential of psychedelics when to comes to caring for and treating those who suffer from various types of mental ill health, including PTSD, severe depression, addiction and the kind of existential distress some experience during the final stages of a terminal illness. Whilst perhaps unfair, it is somewhat inevitable that the general disrepute of psychonaut subcultures presents a distinct problem when it comes to the repute of psychedelic research and researchers. According to Giffort, such tensions are brought to the fore in the figure of Timothy Leary, whose personal and professional biography embodies the way in which elements of psychonaut culture can lead scientists astray, ending careers and even entire research programmes. Coupled with the idea that knowledge of psychedelics is inherently incomplete in the absence of personal experience of such drugs, one can understand why it is that those involved in the renaissance of psychedelic research expend a significant amount of energy when it comes to protecting their scientific legitimacy.

The significance of personal experience is also broached by academic journalist Michael Pollan in his popular book How to Change Your Mind. Again, we find a tension between the kinds of insight offered by experience and research. For example, relating a conversation with Dr. Robin Carhart-Harris (a prominent psychedelic researcher based at Imperial College London’s Centre for Psychedelic Research) Pollan writes “I asked Robin if his hunch was based on personal experience or research, but he made [it] clear [that] this was not a subject he wished to discuss” (Pollan, 2018, p. 296 emphasis added). Equally Amanda Feilding—a minor member of the British aristocracy as well as drug reform activist, psychonaut, researcher and founder of the Foundation to Further Consciousness (since renamed The Beckley Foundation)—is quoted as saying: “I’m a druggie. I live in this big house. And I have a hole in my head. I guess that disqualifies me” (Pollan, 2018, p. 299). It seems clear that proponents of psychedelics are acutely aware of the negative characterisations that can attach to individuals who explore altered states of consciousness for themselves. Evidently, there is a need to address such concerns if psychedelic therapies are to find acceptance within the culture of modern biomedicine and the scientific perspective that forms its underlying worldview.

We suggest Chris Letheby’s Philosophy of Psychedelics can be understood in similar terms, going some way towards legitimatising the place of psychedelics in both academia and biomedicine. It seems clear that a great deal of analytic effort is being expended in service of showing psychedelic drugs—in terms of both the experiences they provoke and any potential treatment they might offer—can be framed and understood in purely naturalistic terms. In effect, Letheby’s central concern is to show that psychedelic research and any medications that might result are not incompatible with the presuppositions of the medico-scientific worldview or, at least, the central presupposition of biomedicine’s epistemic culture, naturalism. Of course, this might strike one as barely worthy of comment. After all, providing a naturalist account of empirical phenomena is the raison d’être of scientific research. However, one must keep in mind that psychedelics are not only connected to a variety of spiritual and animist worldviews. They are also associated with, first, the counterculture and various of its political movements and, second, largely fictional, but nevertheless culturally significant ideas about the connection between mind control and psychedelics.[1] Thus, on the surface there is a need to disassociate psychedelics from non-naturalist worldviews involved in shamanism, but underneath there is a need to disassociate psychedelics from its implicit association with subversive—or, at least, countercultural—political movements and mind control.

Particularly when it comes to the mystical dimension of the experiences induced by psychedelic drugs, Letheby’s account cannot fully preclude the idea that they may have transformative consequences of spiritual and political significance. Indeed, psychedelic drugs would be far less interesting both in general and to researchers if they did not have clear potential to induce or result in significant intrapersonal transformations, including those that alleviate addiction, depression or the symptoms of severe PTSD. What Letheby does aim to show, however, is that spiritual beliefs are not a necessary consequence of the psychedelic experience even if, as the research suggests, those who are given psychedelic drugs commonly describe their experiences as having a spiritual element or dimension.

Image credit: Giorgio Trovato 1. Image used under licence of https://unsplash.com.

Of course, such experiences cannot simply be dismissed. They require an explanation of some kind and Letheby’s solution is to focus on the self; specifically on psychedelic experiences that one might characterise as involving self-dissolution. In this way, we need not accept that either psychedelic experiences are epistemologically problematic hallucinations, nor must we concern ourselves with the non-naturalist metaphysics implied by mystical or spiritual experiences. Instead, we can suppose them to be products of the psychedelic experience whilst maintaining that any transformative consequences—including any therapeutic efficacy—results from the impact of psychedelics on the self, which is itself (pun intended) little more than an illusory construct.

Indeed, this unbinding or (to reiterate Letheby’s use of Iris Murdoch’s morally significant term) unselfing is later presented as the basis for psychedelic spiritual experiences. Ordinarily our phenomenal experience of self is transparent, ordinarily it is a background and taken for granted presupposition. However, the sense of disintegration that psychedelics can induce results in our self-construct becoming “opaque” and, rather than resulting in an objectification of the self, the consequence is an experience of selflessness, or so individuals report. In this way Letheby recasts spiritual experiences as shifts in the phenomenology of the self. Somewhat ironically, the outcome of this philosophy of psychedelics is that the self is simultaneously centred and decentred. The self not only lies at the heart of the psychedelic experience; it is also the object of therapeutic concern and the instrument of its efficacy. Equally, however, through discussion in Chapter 7, the self is shown to be a kind of illusion, a foundational bedrock that is in fact shifting sand.

Comprehensive as it is, Letheby’s account nevertheless leaves some questions open, at least for us. For example, consider the addict comes to know that addiction is not fundamental to who they are or the emotionally repressed man who realises the childhood message ‘boys don’t cry’ is a damaging falsehood. Letheby seems to characterise these epistemological changes in terms of ‘knowing that’. However, it seems likely that many of those who are addicts or who are unable to express their emotions already know such things. What seems to change is the degree to which they believe them and the degree to which they are able to embody those beliefs. Although it seems consistent with Letheby’s focus on the self, it does not seem to be adequately captured by either ‘knowledge that’, or by ‘knowledge how’ or ‘knowledge by acquaintance’ – the two other epistemic categories discussed. What seems to change is the affective relationship between the knower and what it is they know. It is not what is known per se, but the phenomenal and dispositional orientation of the individual to their knowledge or beliefs (Schwitzgebel, 2002), that is, the relationship between the self-construct and what it is that is known, embodied or affectively believed.

How, then, are we to understand psychedelics both in themselves and as potential experiential therapies? It seems to us that they are clearly being positioned as tools for shaping the self, albeit in extremis. As such, they can be considered in Foucauldian terms—as technologies of the self—and positioned alongside the confessional, the self-help book and the psy-sciences more generally. However, doing so reopens the door to the ethico-political significance of psychedelics and psychedelic experiences. Indeed, this is arguably part of Letheby’s thesis, particularly when he suggests that psychedelic drugs may have the potential to be forms of, or routes to, moral (self-)enhancement, something not unlike Murdoch’s conception of unselfing that surfaces the connection between an experience of selflessness and the moral concept of being selfless. Whilst ideas about moral enhancement are commonly advanced as if they were apolitical, this is arguably a problematic aspect of the current debate; given the prior connection between psychedelics and countercultural politics, the broader implications that might attend positioning psychedelics as having the potential for moral enhancement are far from clear.

Image credit: Kunj Parekh. Image used under licence of https://unsplash.com.

Ordinarily, these kinds of concerns—the way in which interventions reframe our understanding of notions of illness, treatment, and patients in specific contexts—might take medicalisation as their focus. At least to some degree, psychedelics present something of a therapeutic step change. Whilst there are other experiential therapies, such as psychotherapy or aversion therapy say, none of those currently used in practice are quite the same as a psychedelic trip. Whilst a talking therapy might be transformative, they are not condensed into such a singular experience. Given the context of experiential therapy, what might medical professionals be expected to know? Consider, for example, the way in which psychiatrists and psychotherapists are required or, at least, advised to directly attend to their own emotional well-being, to the point that they should undergo the kinds of talking therapies or analysis they offer to their patients, either in an ongoing manner or as part of specialist training. Might the same be said of those who prescribe psychedelics: when it comes to such drugs, should medical doctors be knowledgeable by acquaintance?

Of course, this is not a new idea: Leary (1983) and many others—including some contemporary psychonauts—would see the value of such experiences for those who purport to use psychedelics for healing purposes. This could further the notion of shamanism invading healthcare and depending on how psychedelics are eventually medicalised (Noorani, 2020; Noorani and Martell, 2021), could either provide a new treatment for a range of disorders, or bring the healthcare-providing-community into disrepute. The interface between healthcare providers and patients will ultimately be shaped by societal acceptance of psychedelics as viable treatments. In advancing a view that is consistent with naturalism, Letheby’s philosophy of psychedelics will, perhaps, contribute to such acceptance, particularly within the culture(s) of professional biomedicine and, dare we say, medical education.

It is an unavoidable implication of our view that the explanatory meanings attached to psychedelics by Letheby—and, arguably, by those involved in the renaissance of psychedelic research more generally—are representative of a particular culture, one that is defined by the philosophical and scientific world view of naturalism.. Letheby is not, of course, averse to any one individual adopting a supernatural metaphysics as the result of their psychedelic experiences. His only concern is that naturalism can account for such experiences, that they can be reframed in a philosophically parsimonious way, one that does not conflict with the basic presuppositions of the scientific world view. As a result, he secures the legitimacy of psychedelics, psychedelic research and, perhaps most importantly, psychedelic researchers. However, ultimately, the fact that we inhabit our own cultural contexts cannot be neglected and whilst the ethico-political consequences of the therapeutic ethos we inhabit (and are inhabited by) has been well documented, the consequences of introducing the psychedelic experience as a therapeutic agent remains to be understood.

[1] One has in mind the CIA’s research programme MK Ultra, Manson and his ‘Family’, soma in A Brave New World, The Manchurian Candidate, A Clockwork Orange. That the latter two examples do not, in fact, feature the use of psychedelic drugs does not prevent the existence of a cultural association.


Giffort, D. (2020) Acid Revival: The Psychedelic Renaissance and the Quest for Medical Legitimacy. Minnesota: University of Minnesota Press.

Harman, W.W. (1963) ‘The Issue of the Consciousness-Expanding Drugs’, Main Currents in Modern Thought, Volume 20: pp. 5–14.

Leary, T. (1983) Flashbacks. United States: G. P. Putnam’s Sons.

Noorani, T. (2020) ‘Making psychedelics into medicines: The politics and paradoxes of medicalization’, Journal of Psychedelic Studies, 4(1), pp. 34–39. doi:10.1556/2054.2019.018.

Noorani, T. and Martell, J. (2021) ‘New Frontiers or a Bursting Bubble? Psychedelic Therapy Beyond the Dichotomy’, Frontiers in Psychiatry, 12. doi:10.3389/fpsyt.2021.727050

Pollan, M. (2018) How To Change Your Mind: The New Science of Psychedelics. UK. Penguin Books Ltd.

Schwitzgebel, E. (2002) ‘A Phenomenal, Dispositional Account of Belief’, Noûs, 36(2), pp. 249–275. doi:10.1111/1468-0068.00370.

Nathan Emmerich is a Senior Lecturer in Bioethics at the Australian National University. Based in the Medical School he is the lead for Professionalism and Leadership in Phase One of the MChD. He also convenes Bioethics and Society, a capstone course for various ANU biology degree programmes that is taken by students across the university. His research is interdisciplinary in nature and has recently focused on various issues including care at the end of life, conscientious objection and ethical expertise. He is a member of the Australian Association of Bioethics and Health Law’s (AABHL) executive committee. Follow Nathan on Twitter @BioethicsAus.

Bryce Humphries is presently undertaking the MChD at the Australian National University. He is interested in psychiatry as a potential future specialism and, reflecting this, he is currently engaged in an independent research project analysing the sociocultural interface between historic and emerging use of psychedelics and the biomedical paradigm. Follow Bryce on Twitter @BryceHumphries6.

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