Philosophy of Psychedelics

Today's post is by Chris Letheby (Western Australia/Adelaide) on his new book Philosophy of Psychedelics (OUP 2021).

We are in the midst of a psychedelic renaissance. “Classic” psychedelic drugs such as LSD and psilocybin are the objects of renewed scientific interest. Despite the chequered reputation of these substances, recent clinical trials have shown that psychedelics can be administered safely in controlled conditions, and may have a role in the treatment of various psychological maladies. There is even talk of a “new paradigm” in psychiatric treatment. 

But psychedelic-assisted psychotherapy (“psychedelic therapy”) has several unusual features that distinguish it from standard psychiatric treatments and raise intriguing questions. In my book Philosophy of Psychedelics (OUP 2021) I tackle some of these questions.

The most striking feature of psychedelic therapy is that it involves the induction of a dramatically altered state of consciousness. Patients with anxiety, depression, or addiction are screened, prepared, and typically given psychotherapeutic sessions before and after drug administration. But the centrepiece of the treatment is one to three supervised sessions in which the patient receives a moderate-to-high dose of a psychedelic.

Psychedelics’ experiential effects are highly variable, being affected strongly by the user’s psychological state and the surrounding environment. But under conducive conditions, a high proportion of patients report a complete mystical-type experience, as defined by psychometric questionnaires. 

The construct comes from the work of William James and Walter Stace, and refers to a transcendent experience in which space, time, and the sense of self fade away, replaced by apparent unity with “another Reality that puts this one in the shade” (Smith 2000, p. 133). One of the most robust findings in psychedelic science, across multiple studies and populations, is that good clinical outcomes are strongly predicted by the occurrence of this specific type of experience.

What should we make of this? If, like Michael Pollan, we are sympathetic to philosophical naturalism, which holds that there is no other Reality, then we might wonder whether psychedelic therapy is “simply foisting a comforting delusion on the sick and dying” (Pollan 2015). 

This possibility is especially salient when we consider the best-studied application of psychedelic therapy: the reduction of existential distress in terminally ill patients. It is easy to imagine that psychedelics might benefit such patients by instilling a deep, experientially-backed conviction in the existence of another, transcendent Reality.

In my book I respond to this concern, which I call the Comforting Delusion Objection to psychedelic therapy. The Objection alleges that (1) naturalism is true; (2) if naturalism is true, then the epistemic (knowledge-related) status of psychedelic therapy is poor; (3) if the epistemic status of psychedelic therapy is poor, then we should hesitate to prescribe this treatment; therefore (4) we should hesitate to prescribe this treatment. 

Existing responses involve (a) denying premise 1 and asserting the existence of another Reality; (b) denying premise 3 and holding that the epistemic status of psychedelic therapy is relatively unimportant; and (c) accepting the conclusion.

I take the relatively untrodden path of arguing against premise (2). I assume the truth of a naturalistic worldview and set out to show, within these confines, that the epistemic status of psychedelic therapy is better than one might suppose. First, its epistemic risks are smaller than they appear: psychedelic therapy does not, after all, work mainly by inducing comforting metaphysical beliefs, but by facilitating the revision of dysfunctional self-related mental representations. Second, this process involves the acquisition of genuine insights—significant epistemic benefits compatible with a naturalistic worldview. 

The ultimate conclusion is that the Comforting Delusion Objection fails. Psychedelic therapy is a defensible and seriously promising treatment, even given naturalistic assumptions and a strong commitment to the importance of truth and knowledge.