Self and Knowledge in Psychedelic Therapy




Predictive processing
Epistemic justification
Self know-how
Epistemic agency

How to Cite

Letheby, C. (2022). Self and Knowledge in Psychedelic Therapy: Reply to Commentaries on Philosophy of Psychedelics. Philosophy and the Mind Sciences, 3. (Original work published April 19, 2022)


Much of my book Philosophy of Psychedelics is devoted to elaborating and defending two basic claims: that psychedelic therapy works mainly by changing mental representations of the self, and that it has many epistemic benefits consistent with a naturalistic worldview. The commentaries in this symposium generally focus on one or the other of these claims. On the mechanistic front, the commentaries by Hoffman and by Martin and Sterzer seek to supplement my account by drawing attention to factors it does not emphasize. In this reply I agree with most of their claims, but propose some important qualifications. Meanwhile, the commentaries by Lyon and Farrenikova and by Colombo challenge some core commitments of my account. I agree with many of their claims, but defend some of these core commitments. On the epistemological front, Bortolotti and Murphy-Hollies endorse the overall shape of my account and make some productive connections to ideas concerning agency-first epistemology and self know-how. Caporuscio brings into play the idea of self-shaping, which connects to self know-how, but argues against certain core claims of my account. I endorse many of these claims about agency-first, self know-how, and self-shaping, but propose some important qualifications. Finally, Fink agrees that psychedelic experiences can have some epistemic benefits, but argues that these do not pertain to epistemic justification, and that the main benefit is increased understanding. I am sympathetic to Fink’s proposal about understanding, but criticize some of his arguments for the thesis of Psychedelic Justification Impossibilism.


Bortolotti, L., & Murphy-Hollies, K. (2022). The agency-first epistemology of psychedelics. Philosophy and the Mind Sciences, 3.

Bruin, L. de, & Strijbos, D. (2020). Does confabulation pose a threat to first-person authority? Mindshaping, self-regulation and the importance of self-know-how. Topoi, 39(1), 151–161.

Caporuscio, C. (2022). Belief now, true belief later: The epistemic advantage of self-related insights in psychedelic-assisted therapy. Philosophy and the Mind Sciences, 3.

Carhart-Harris, R., Leech, R., Hellyer, P., Shanahan, M., Feilding, A., Tagliazucchi, E., et al. (2014). The entropic brain: A theory of conscious states informed by neuroimaging research with psychedelic drugs. Frontiers in Human Neuroscience, 8.

Colombo, M. (2022). Serotonin, predictive processing and psychedelics. Philosophy and the Mind Sciences, 3.

Davis, J. H., & Thompson, E. (2015). Developing attention and decreasing affective bias: Toward a cross-cultural cognitive science of mindfulness. In Handbook of mindfulness: Theory, research, and practice (pp. 42–61). New York, NY, US: The Guilford Press.

Dietrich, A. (2003). Functional neuroanatomy of altered states of consciousness: The transient hypofrontality hypothesis. Consciousness and Cognition, 12(2), 231–256.

Fink, S. B. (2022). The epistemic benefits of psychedelics: Contra knowledge, pro understanding. Philosophy and the Mind Sciences, 3.

Gallimore, A. R., & Strassman, R. J. (2016). A model for the application of target-controlled intravenous infusion for a prolonged immersive DMT psychedelic experience. Frontiers in Pharmacology, 7.

Garcia-Romeu, A., R. Griffiths, R., & W. Johnson, M. (2014). Psilocybin-occasioned mystical experiences in the treatment of tobacco addiction. Current Drug Abuse Reviews, 7(3), 157–164.

Girn, M., Mills, C., Roseman, L., Carhart-Harris, R. L., & Christoff, K. (2020). Updating the dynamic framework of thought: Creativity and psychedelics. NeuroImage, 213, 116726.

Hendricks, P. S. (2018). Awe: A putative mechanism underlying the effects of classic psychedelic-assisted psychotherapy. International Review of Psychiatry, 30(4), 331–342.

Hoffman, S. (2022). Positive affect and Letheby’s naturalization of psychedelic therapy. Philosophy and the Mind Sciences, 3.

Johnson, M. W. (2022). Psychedelic science needs philosophy. Philosophy and the Mind Sciences, 3.

Letheby, C. (2019). The Varieties of psychedelic epistemology. In N. Wyrd, D. Luke, A. Tollan, C. Adams, & D. King (Eds.), Psychedelicacies: More food for thought from Breaking Convention.

Letheby, C. (2021). Philosophy of Psychedelics. Oxford University Press.

Lyon, A., & Farennikova, A. (2022). Through the psychedelic looking-glass: The importance of phenomenal transparency in psychedelic transformation. Philosophy and the Mind Sciences, 3.

Martin, J. M., & Sterzer, P. (2022). How level is the ’Cognitive Playing Field’? Context shapes alterations in self-conception during the psychedelic experience. Philosophy and the Mind Sciences, 3.

McGeer, V. (1996). Is ”self-knowledge” an empirical problem? Renegotiating the space of philosophical explanation. The Journal of Philosophy, 93(10), 483–515.

Metzinger, T. (2004). Being No One: The Self-Model Theory of Subjectivity. MIT Press.

Moran, R. (2012). Authority and Estrangement: An Essay on Self-Knowledge.

Nichols, D., Johnson, M., & Nichols, C. (2017). Psychedelics as medicines: An emerging new paradigm. Clinical Pharmacology & Therapeutics, 101(2), 209–219.

Noorani, T., Garcia-Romeu, A., Swift, T. C., Griffiths, R. R., & Johnson, M. W. (2018). Psychedelic therapy for smoking cessation: Qualitative analysis of participant accounts. Journal of Psychopharmacology, 32(7), 756–769.

Revonsuo, A. (2006). Inner Presence: Consciousness as a Biological Phenomenon. Cambridge, MA, US: MIT Press.

Safron, A. (2020). On the varieties of conscious experiences: Altered beliefs under psychedelics (ALBUS). PsyArXiv Preprints.

Sessa, B. (2008). Is it time to revisit the role of psychedelic drugs in enhancing human creativity? Journal of Psychopharmacology, 22(8), 821–827.

Sui, J., & Humphreys, G. W. (2015). The integrative self: How self-reference integrates perception and memory. Trends in Cognitive Sciences, 19(12), 719–728.

Tulver, K., Kaup, K. K., Laukkonen, R., & Aru, J. (2021). Restructuring insight: An integrative review of insight in problem solving, meditation, psychotherapy, delusions and psychedelics. PsyArXiv Preprints.

Wang, H., Humphreys, G., & Sui, J. (2016). Expanding and retracting from the self: Gains and costs in switching self associations. Journal of Experimental Psychology: Human Perception and Performance, 42(2), 247.

Watts, R., Day, C., Krzanowski, J., Nutt, D., & Carhart-Harris, R. (2017). Patients’ accounts of increased “connectedness” and “acceptance” after psilocybin for treatment-resistant depression. Journal of Humanistic Psychology, 57(5), 520–564.

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