The Metaphysics of Psychedelics (thoughts on Chris Letheby’s new article)

Here is a fantastic new publication on psychedelics by Chris Letheby: “Psychedelics: Recent Philosophical Discussions.”It will appear in T. Schramme and M. Walker (eds.), Handbook of the Philosophy of Medicine (Springer, forthcoming). 

The whole paper is worth a close read, as it provides a digestible summary of the major philosophical questions that have arisen during the last couple decades of renewed academic and medical interest in psychedelics. Of greatest interest to me is the epistemic (and indeed, ontological!) status of psychedelic experiences. 

In earlier work, Letheby argues that non-naturalistic metaphysical beliefs may be “comforting delusions.” In the case of, eg, some form of panpsychism (or panexperientialism), I would contest the idea that dissolving the modern “buffered self” (see Charles Taylor, 2007) so as to sensitize ourselves to the multitude of nonhuman experiential agencies swarming all about us is necessarily “comforting.” On the contrary, it can be downright terrifying, especially for those previously committed to an anthropocentric conception of sentience and agency. Note also that while some panpsychisms may open the door to nonphysical or nonbiological agencies, there is nothing supernatural about coming to have direct experience of our own bodies as vast cellular ecosystems, or the surrounding living world as a network of nonhuman sentience.

Naturalism (aka, materialism or physicalism) is itself a contentious metaphysical position. As many contemporary philosophers have argued (eg, Philip Goff, Peter Sjöstedt-Hughes), the best available scientific evidence is compatible with multiple metaphysical positions, including various forms of idealism and panpsychism, and some forms of dualism. Thus we need other criteria than just the data provided by the natural sciences to make such metaphysical determinations. Perhaps these other criteria should include the pragmatic consequences and documented psychological benefits of various views? 

Letheby (2016, 2021) suggests that if psychedelics do work therapeutically by inducing non-naturalistic beliefs, this would constitute an important objection to their clinical use. Why is that? What if the metaphysics or world view of scientific materialism is itself a risk factor for psychological ailments like depression and anxiety? I explore many of these questions (including Letheby’s concern) in more depth in a white paper originally written for the Templeton Foundation: “Philosophical and Religious Implications of Psychedelically Occasioned Mystical Experience and Belief Change” (2022).