On Drugs: Psychedelics, Philosophy, and the Nature of Reality

by Justin Smith-Ruiu

“Like the best psychedelic experiences, On Drugs estranges the familiar, familiarizes the strange, and returns us to reality (whatever that is) with a broadened sense of the possible. Justin Smith-Ruiu is simply one of the most interesting thinkers alive, and he has found an ideal subject for his peculiar brand of brilliance.” —Christopher Beha, author of The Index of Self-Destructive Acts


In the late, post-lockdown days of the pandemic, grappling with personal loss and existential uncertainty, Justin Smith-Ruiu found himself standing in a California cannabis dispensary, pondering a question his tribe of fellow philosophers have often dismissed as too How did I get here? That moment marked a transition for him—it was the start of a journey Smith-Ruiu would take to experience his own mind and the world around him in a new, clarifying way.



On Drugs blends autobiography, intellectual history, and philosophical inquiry to explore the transformative impact of psychedelics on human consciousness and thought. Drawing on his personal experiences as ‘an articulate guinea pig,’ Smith-Ruiu argues that psychedelics upend our assumptions about the nature of reality—and thus force a reckoning with the very foundations of Western philosophy.



Provocative, profound, and deeply personal, On Drugs points toward a radically new way of thinking about the world and our capacity to understand it.

Genres: Philosophy, Nonfiction, Science

280 pages, Kindle Edition

Published September 23, 2025

About the author

Also writes as Justin E. H. Smith.

Reviews

[Mary Holt-Wilson · Rating 3 out of 5]

I'm not sure I learned much more than I already knew about any of the titular items, but I still found this an interesting read.

[Ben Gilbey · Rating 2 out of 5]

I was expecting something else I think.

With the title of this book, I was hoping to find a dense, detailed examination of psychedelic experiences and some of the possible philosophical implications of such experiences. This is on offer, but in a much more superficial form that I had hoped for. For example, Smith-Ruiu touches on psychedelic experiences in relation to Phenmonenology, and just begins to think about such experiences in Phenmenological terms, but then moves on, and it feels very half-baked. This is partly because this book is much more memoir than I had assumed it would be. As such I would suggest it is not really a philosophical work. It does not feel particularly rigorous or though through. Another disappointing example is when Smith-Ruiu mentions Deleuze and Guttari's works. Some of their ideas are glanced over and I would argue misrepresented, and any exploration of their thought in relation to psychdelic experience is pretty much absent.

If you have never read any work on psychdelics before, and are curious about the potential personal implications of psychedelics for yourself, and want to read about someone elses experiences and the implications it had for them, then maybe this would be a worthwhile read. It might spark a deeper curiosity to look further into psychedelics and their philosophical implications for yourself.

However, I would definitely frame this authors conclusions about psychdelics as secondary to his own personal process, which this book is clearly more focused on than on any attempt to be philosophically rigorous, critical, and objective about the complex reality of psychedelics and how they affect our experience of ourselves and reality itself.

Smith-Ruiu tells us how psychedelics ultimately brought him back to church, and reconnected him to memories of his childhood in the church. I love that for him, it's genuinely moving. But in the process, it feels like rigorous and interesting philosophical inquiry went out the window. This could have led to a fascinating reflection on what psychedelics evoke for us, and again, Smith-Ruiu sort of takes us down that road, but its more about his own personal experience than an attempt at rigorous, critical philosophical thought.

So, if you want a memoir thats laced with a smattering of philosophy, history, and some drugs, this is for you. But don't let the title decieve you, its not that interesting philosophically speaking.

[Gabrielle · Rating 4 out of 5]

Great book! In some ways I like it better than Michael Pollan's book, although not quite as much as I loved "Storming Heaven" or "The Varieties of Religious Experience" (the brilliant ur-text on altered states of consciousness). Personally, I took hallucinogens as a teenager because I wanted to explore different realities and understand better how the brain creates consciousness, and Smith-Ruiu goes deeper into the questions that interested me than previous books on hallucinogens have. Two statements at which I especially applauded were:
"ALL brains are on drugs." As a neuroscientist I'm keenly aware of this fact, but he finally said it straight out.
"Hallucinogens are MEANT to blow your mind" (loose quote). I totally agree! Micro-dosing is for wimps, in my view (although I exclude from this diss people who micro-dose because they've tried regular antidepressants without benefit). If you take hallucinogens to feel more "normal", you're missing the point. LSD showed me exactly to what extent the reality we "normally" experience is a somewhat arbitrary constructions of our brains, and that's a lesson I think would be good for many people to learn -- even though learning can be quite scary.
On the down side, I thought the author got too deep into history of philosophy and what various philosophers have had to say about the nature of reality, and I skimmed through some of those sections. Really, "ALL brains are on drugs" pretty much sums up the situation for me, along with the author's thought experiments about alien species who are more or less drugged out.

[Charles Rizzo · Rating 2 out of 5]

I purchased this book after reading the New York Times review.

Although Justin's personal story is interesting i find it falls short of any real discovery. It seems as though he was in search of a common truth and at least for now has ended where he began. He argues that the inspiration of the "search for truth" that guided many of the past luminaries is supported by some type of chemistry; this seems to be his way of justifying his experimentation with psychedelics. I can understand his reasoning since i personally have experiment with LSD many time in the past and found wonder in those hours but like Justin it soon faded. It can open the doors to some new and transformative perception but it only can open the door, it wont let you in.
In William James's "Varieties of Religious Experience" he writes about his own use of chemistry to find truth and shares its short comings in his search; he understood that the door existed but he could not enter.

The mystery of transcendency has been written about through many voices over the ages and i have never personally read about psychedelics or other chemicals that assisted in these transformations. It is a gift that appears to some for whatever divine intervention and it is not connected to drugs or religion. A very best example of this is Dante's journey in the "Divine Comedy" in which man finds his destiny as he releases all of his vices to find Paradiso.

I wish Justin well but i know his journey is far from over.

[Sam · Rating 1 out of 5]

I once had a boss that was impressively intelligent but spoke in such a way that everyone else struggled to understand him. He didn't use obscure vocabulary, it was that he strung medium-length words together in unusual, exhausting ways. It reminded me of my mission, when an Armenian guy was using a bunch of slang (imagine a non-native English speaker hearing "that was mid, it’s giving type wild 6–7, bro thought he was him… yeah, we’re cooked, chat") and asked me if I understood, and I said "I understand, but I don't get it (հասկացա, բայց չջոգեցի)". It was mentally exhausting to sift through words I knew without being able to grasp their meaning.

This author and that boss would get along so well. I read a couple sentences to Kelsie – one with 6 commas – and she said it sounded like Joey from Friends running every word in his letter through a thesaurus (this is no time for dinosaurs, Ross!).

I've made it through some challenging books, but on subjects that deserve that density: fossils, quantum physics, and Russian philosophy. I did not expect a book about psychedelic drugs to take the cake! These drugs supposedly open your eyes to the world around you but this book only helped me get some extra shut-eye.

Fascinating topic, insufferable writing. DNF at 25%.

[Kara Froese · Rating 2 out of 5]

As a recently deconverted Christian, and someone curious about different world experiences (including a curiosity about psychedelics) I was excited to read this book. Imagine my disappointment upon finding out 95% of the way through that the author recently became a devout Catholic and that this clearly drastically shapes his conclusions about psychedelics and how people should use them. He even argues that a trip is the same as a religious experience. As an ex-Christian, I have a lot of thoughts on that, but don't care that much to refute his claim.

Dare I say that philosophy in general interests me very little? I'm not convinced that it's anything but a bunch of dudes who have an elevated sense of importance of their own ideas of the world (and think that there can be a right or wrong way of thinking). So I guess maybe this book wasn't written for an audience like me, and much of it probably went over my head.

[Richard Thompson · Rating 4 out of 5]

It's an interesting effort - Looking at psychedelic drugs from a philosophical perspective. What does the psychedelic experience tell us about the mind body problem, the truth or falsity of sense impressions, and our understanding of the world? Does a philosophical perspective on psychedelics give new insights into epistemology and ontology? There's a definite connection that is worth exploring, and the book makes some good initial steps in that direction. You don't need a degree in philosophy (nor do you need to have taken psychedelics yourself) to understand the discussion. Still, I came away from the book feeling that there are further depths to be plumbed both on the drug side and on the philosophy side, though that may be hard to do since most drug people don't care about philosophy, and most philosophers turn up their nose at psychedelic drugs as a vehicle for doing philosophy.

[Kathy · Rating 3 out of 5]

I finished it. That counts for something. This vacillates between philosophical treatise and memoir. The descriptions of what it’s like to be on psychedelic drugs were bizarre and sort of comical. He made some interesting points that I couldn’t regurgitate back. I was disappointed by the conversion to Catholicism.

[Mindaugas Genutis · Rating 1 out of 5]

It’s a rather shallow take on a fascinating topic. Instead of exploring it in depth, the author chose to provide a superficial overview of what’s already known. A book like this could easily have been written by AI, it shows little evidence of genuine investigation or original research.

[Maddy Walock · Rating 3 out of 5]

I feel like there were interesting points and stories but altogether I didn’t find this book teaching me much nor giving deep insight. Still interested in the topic, I want to read more literature like this.

[Rick · Rating 2 out of 5]

Like an Erowid trip report that meanders into a random assortment half-digested history and philosophy works. Despite copious self-revelations, Smith-Ruiu denies that this is a memoir. If it had been, it might have been much better (and more focused) than whatever this is.

[Calvin Baker · Rating 2 out of 5]

Pace the author, this book did not seem to me to raise any interesting, substantive philosophical questions. My main takeaway is that doing psychs can shift your priors around by making certain (wacky, minority) philosophical positions like theism and panpsychism appear more plausible to you.

[AMAO · Rating 5 out of 5]

📚📚📚📚📚

[Jim Parker · Rating 5 out of 5]

Certainly much food for thought. Full of quotable material. I suspect almost no one will agree with everything the author presents and some may even agree with nothing. I think most people will some material with which they agree.