Psychedelics and the hard problem of consciousness

How the psychedelic experience can shed light on the mind-body problem

The map is not the territory. The modelled brain is not consciousness. ‘This’ – the ineffable quality of subjective experience – is consciousness. No scientific description can ever reach it. The psychedelic experience allows us to get behind our models, and provides us with a special, unitary knowledge of consciousness; shedding new light on the infamous hard problem, writes Jussi Jylkkä.


This, my experience right now, is what it feels like to be alive. But this cannot be inferred from science alone. David Chalmers calls this the “hard problem” of consciousness. Psychedelic experience can shed light on the problem, as it demonstrates how I know my consciousness in a non-conceptual and non-reflective way through being it. I call such knowledge “unitary”, as it is not about anything. It is simply the brute happening of a process: this. In contrast to unitary knowledge, scientific models and observations only give relational knowledge that is about something distinct. Thus, psychedelic experience shows that consciousness is part of the concrete reality that science merely models. This is what science models as “physical”.

Consciousness is this, matter is that something

The hard problem of consciousness is the problem of why it is that any physical processes feel like anything ‘from the inside’. A closely related problem is the epistemic gap, or why it is impossible to infer from science what experiences feel like, or that subjective consciousness exists at all. Psychedelics can shed light on these problems through demonstrating a categorical difference between how I know my own consciousness, and what type of knowledge science gives.

Psychedelic experience shows that consciousness is part of the concrete reality that science merely models.

To understand the relationship between consciousness and matter, we must understand what consciousness is, and what matter is. To begin with the latter, matter (or the physical; I take these to be synonymous) is whatever it is that physics models. As Galen Strawson puts it, “matter” is the ultimate natural kind term: it refers to that something, whatever it is, that produces observations of atoms and molecules, and that modern physics models as, say, interaction between quarks. [1] However, “interaction between quarks” is merely a theoretical model in our minds, which refers to that something that matter truly is. Observations of atoms and molecules are merely sensations in our minds. The word “matter” does not refer to these sensations, but instead to what produces them. Beyond our observations and theories, matter is a mystery.

What is consciousness? For me it is this, sitting in front of my computer, thinking about philosophy at 9am on a Saturday morning during my summer vacation. Consciousness is this thinking process now, the ache in my back, the sound of the refrigerator, the sight of trees trembling in late summer breeze. The slight fear of deadline. Consciousness has been characterized in countless ways throughout history, as “qualitative”, “non-spatial”, “soul”, “Brahman”, etc., but all these are merely words, and the word is not the object. Beyond words, consciousness is simply this, what is immediately present every moment. This is consciousness when it is not called “consciousness”, this is the flow of experience when it is not called “the flow of experience”. It is this when it is not called “this”.

Beyond words, consciousness is simply this, what is immediately present every moment..

How do we know matter and mind? Matter is known through observations and theories. I call such knowledge relational, because it is distinct from what it is about: the atomic model is about that something that we call “atom”; our observations of quantum interference are produced by that something that we model as “quarks”. As to what matter is outside my consciousness, I cannot know, since knowing is in consciousness. My own consciousness, in turn, I know simply through being it, through being this. I call such knowledge unitary. It is not “about” anything, nor is it “possessed” by anyone—it is simply the process that happens here and now. This is demonstrated by unitary experiences that can be produced by meditation, or more easily, through psychedelics.


Psychedelic consciousness

Psychedelic substances such as psilocybin, LSD, or cannabis can occasion mystical experiences, whose central feature is unity. In the right set and setting, psychedelics can catalyse the dissolution of the experience of a “subject” that is distinct from the “objects” of its knowing. For example, the journalist Michael Pollan describes his experience of listening to Bach’s sonatas under the influence of psilocybin as follows:

[I] lost whatever ability […] to distinguish subject from object, tell apart what remained of me and what was Bach’s music […] I became a transparent ear, indistinguishable from the stream of sound that flooded my consciousness until there was nothing else in it.[2]

In this experience, there is no longer “I” or “subject” who knows or undergoes their experience, there is just the experience itself, the brute flow of consciousness. There is no subject who undergoes or knows experiences, there is merely the experience itself, the brute happening of a process. The psychedelic experiencer knows their experience in a unitary way through being it. Such “knowing” is not conceptual; it is non-reflective and non-intellectual. It is unitary: the experiencer knows their consciousness through being it, and then there is no longer an “experiencer” or “subject” distinct from their consciousness. There is merely the happening of a process, and its happening constitutes its knowing.

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Zen philosophy emphasizes unity. Or rather, it emphasizes non-duality, as “unity” is also merely a word that brings in dualism. It emphasizes the limits of language and the ineffability of consciousness in-itself. Explicitly aware of its paradoxicality, Zen philosophy uses language to transcend language, or to become aware of the limits of language. Consciousness in-itself is non-conceptual and beyond any reflective characterizations of it; it is simply this, what is happening right here right now, during every moment of my (subjective) existence. Even my writing now is this, as “writing” is merely a word that refers to the process that is happening right now. I cannot escape this, although when I try to reach it reflectively or through words, it escapes.

Psychedelic experience demonstrates this, that is, unitary knowledge that is constituted by consciousness itself. It is not about anything; it is non-intentional. It is the happening of what science models as a neural process, but which for me is simply this. In itself, consciousness is non-conceptual and ineffable. If I try to capture it in concepts, it vanishes, as concepts imply a reflective standpoint distinct from this.


The epistemic gap redefined

Neuroscience models consciousness as a specific kind of neural process. Through my own experience, I know what the term “neural correlate of consciousness” refers to: it is this. We can agree with the physicalist that consciousness is indeed “nothing but” a neural process: it is what science models as a “neural process”. We can even agree with the eliminativist that there are no “qualia”, if that means something distinct from the processes or properties that science models. To account for the epistemic gap, we need not postulate the existence of properties beyond those that science models; we must only acknowledge that science is limited to modelling reality. The epistemic gap is the difference between the model and the modelled.

In contrast to what, e.g., Philip Goff argues, we need not postulate the existence of unobservable “intrinsic” or “categorical” properties or “quiddities” to find a place for consciousness in the scientific worldview. Instead, we must only see that the scientific worldview is merely a view on the world. Science is not limited to modelling some special class of properties (Goff calls these “extrinsic”); instead, it is limited simply to modelling.

In itself, consciousness is non-conceptual and ineffable. If I try to capture it in concepts, it vanishes, as concepts imply a reflective standpoint distinct from this.

This is what science models as “neural correlate of consciousness”. Psychedelic experience shows how I know this in a unitary and non-conceptual way through being it, whereas science only gives relational knowledge about this. This is the reason for the epistemic gap: It is impossible to infer this, the happening of a concrete process, from its scientific description.


Idealism, panpsychism, materialism…?

The hard problem is more than just the epistemic gap, it is also the question of why brain processes feel like anything in the first place. The hard problem is essentially a problem for physicalism, which holds that consciousness is physical: how can the physical be experiential, given that science gives us no clue about this? Through psychedelic experience, it is possible to see how this is reality, and how science merely gives models about reality. Thus, psychedelic experience demonstrates not only the absoluteness of this, but also the relativity of scientific images. It reveals a mystery: what is the physical in itself beyond our physical models of it as “quarks”, “energy”, of “fields”? The only access I have to reality in itself is this: this is what science models as “physical”. If ontological monism is true and everything is made of one single kind of substance, then everything is of the same kind as this. This is true even according to standard physicalism: if consciousness is a neural process, then consciousness is made of quarks—in other words, whatever quarks are, they are the constituents of consciousness. [3] You can call this “idealism” or “panpsychism” or “materialism”, but all these are merely words. This is real, and psychedelic experience shows what this is.



[1] Strawson, G. (2003). Real materialism. In M. Antony, Louise & N. Hornstein (Eds.), Chomsky and His Critics (pp. 49–88). Malden, MA: Blackwell.

[2] Pollan, M. (2018). How to Change Your Mind (p. 254). New York: Penguin Books.

[3] See Figure 1 in Jylkkä, J., & Railo, H. (2019). Consciousness as a concrete physical phenomenon. Consciousness and Cognition, 74, 102779.

Another article on psychedelic philosophy by Jussi Jylkkä, “Mary on Acid”, will appear in 2022 in the volume Philosophy and Psychedelics, edited by C. Hauskeller and P. Sjöstedt-Hughes (Bloomsbury Academic).


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