We have two sources of media for this discussion. First is an interview with Michael Pollan from KERA's Think podcast, exploring what we know about the mysteries of consciousness. The second is a written reference that expands on the interview and orients us in the prevailing ideas on this subject.
Listen to the episode at Think from KERA (with transcript)
Click any theory to read a summary. Positions are approximate, not rigid.
Names and ideas marked with a † appear in the Pollan interview.
These terms overlap, slide into each other, and mean different things in different traditions. That slippage is part of the problem, and part of the discussion's territory. Here is how this document uses them:
There is no agreed-upon definition. Everyone knows consciousness from the inside, yet no one has been able to say precisely what it is. One influential way in, from the philosopher Thomas Nagel†: if there is something it is like to be a certain creature, any felt quality at all, then that creature is conscious. Philosophers call these felt qualities qualia. But the formulation is a starting point, not a settled answer. It tells us what consciousness does without telling us what it is.
The philosopher David Chalmers drew a now-famous distinction. The easy problems of consciousness (still very hard in practice) involve explaining how the brain processes information: how neurons fire, how you recognize a face, how memory works. The hard problem† asks something different: why does any of that processing produce an inner experience at all? You could, in theory, have a being that does everything you do, that talks, responds, and navigates the world, but has no felt experience inside. Why aren't we that? Why are the lights on?
No one has a consensus answer.
The serious positions spread across a wide spectrum.
At one end: consciousness depends on brains. This is the working assumption of most neuroscience. Subjective experience arises from certain kinds of physical complexity; explain the brain fully, and you've explained consciousness. The challenge is that no one has shown how neural activity gives rise to felt experience; only that the two correlate.
In the middle: consciousness arises from how information is organized. Global Workspace Theory† proposes that consciousness happens when information is broadcast widely across the brain, becoming available to many processes at once, like a spotlight illuminating a stage. Integrated Information Theory (IIT)† takes a different approach. A common assumption in science is that if a system behaves the right way (processes the right information, produces the right outputs) then what it's built from doesn't matter. IIT rejects this. Rather than starting from the brain, it starts from the properties of experience itself and asks what kind of physical system could account for them. It proposes that any system with the right kind of intrinsic causal structure, roughly, a system whose parts are woven together so that the whole does something none of the parts can do alone, has some degree of experience, measured by a quantity called Φ (phi)†. And because structure matters, not just function, a digital simulation of your brain, even if it behaved identically, might have no consciousness at all. IIT's metaphysical commitments are deliberately left open; it has been interpreted as compatible with physicalism, panpsychism, and even idealism.
At the other end: consciousness is fundamental. Panpsychism† holds that experience is a basic feature of matter itself, that even simple physical systems have some rudimentary form of it, and complex consciousness emerges from combination. Analytic idealism goes further: consciousness isn't produced by matter at all. Matter is what consciousness looks like from the outside. Several contemplative traditions (Advaita Vedanta, Kashmir Shaivism, certain schools of Buddhism) have held versions of this position for centuries, though they point to something the English word "consciousness" only partially captures: not subjective experience in the Western sense, but something prior to the split between subject and object.
The plant experiments Pollan describes sit uncomfortably on this spectrum. If a Venus flytrap can be put to sleep by an inert gas, something is being switched off. But what? The answer depends on where you think consciousness lives.
The Western tradition, from Descartes forward, assumed consciousness was primarily about thought: rational, reflective, located in the cortex. "I think, therefore I am."
The neuroscientist Antonio Damasio† reversed this. He argues that consciousness may begin not with thought but with feeling, the body's basic signals about its own state. Hunger, pain, temperature, the sense that something is wrong or right. These register in the brainstem, not the cortex, and they may be the foundation on which everything else is built. On this view, I feel, therefore I am is closer to the truth. The cortex is a late addition. The body knew first.
This matters for the question of artificial consciousness. Computers can simulate thought convincingly. But simulating a feeling is not the same as having one. If consciousness is rooted in the body's vulnerability, its capacity to suffer, to be at risk, to die, then a system without a body may be missing the thing that makes experience weigh something.
When David Hume† looked inward in the 1740s, he reported that whenever he entered most intimately into what he called himself, he always stumbled on some particular perception: warmth, cold, pleasure, pain. He never caught the self itself. Only the thoughts, never a thinker. The self, he concluded, is a bundle of experiences with no one at the center, a fiction we construct because it's useful.
The Buddhist tradition arrived at a similar conclusion by a different route. The doctrine of anattā† (no-self) holds that what we call "self" is a dynamic process: five aggregates (form, feeling, perception, mental formations, and cognizing awareness) arising and passing away moment to moment. There is no permanent, independent entity underneath. The sense that there is one is the root of suffering.
And yet the self feels real. We navigate every relationship, every decision, every memory as though there's someone home. The Buddhist response is pragmatic: the self has conventional reality (it works as a social tool) but no ultimate reality. It's like a wave on the ocean: real as a pattern, but not a thing separate from the water.
Modern neuroscience offers its own version. The brain constructs a self-model, a representation so seamless we can't see it as a representation. We mistake the map for the territory. The philosopher Thomas Metzinger calls this a "transparent" self-model: you look right through it and see what feels like a real self, the way you look through a clean window and see what feels like an unmediated world.
Pollan's flotation tank experience suggests something related. Remove the external inputs that reinforce the self (sensation, social friction, the resistance of the physical world) and the self begins to dissolve. It may be less a substance than a pattern maintained by contact.
Every theory of consciousness runs into the same wall. The tool we're using to investigate consciousness is consciousness. We can't step outside it. Thomas Nagel put it sharply: we can study a bat's brain in any detail we want, but any conception we form of what it is like to be a bat will be shaped by our own point of view, not the bat's. Objective description, no matter how complete, misses the subjective character entirely.
This circularity haunts the field. The competing theories (at least 22 by one count, over 200 by another) keep producing explanations that account for the mechanisms of consciousness without touching the experience of it. They explain the easy problems brilliantly. The hard problem remains.
Some thinkers, particularly in the phenomenological tradition, argue this isn't a bug but a feature. If consciousness is the condition for all experience, then studying it from outside is like trying to see your own eyes without a mirror. The right approach isn't to explain consciousness away but to investigate it from within, which is what contemplative traditions have been doing for millennia.
Most of the theories described above share a starting assumption: that matter is fundamental, and consciousness is something that needs to be explained, derived from something more basic. The hard problem only exists inside this frame. It asks: how does matter produce experience?
That assumption is not arbitrary. It's the frame that got us antibiotics, brain imaging, and everything neuroscience has learned about how damage to specific brain regions alters specific experiences. Even theories like IIT, which don't require brains specifically, still treat consciousness as something that arises from physical organization. For many scientists and philosophers, the materialist frame isn't a bias. It's a discipline: start with what you can measure, and don't multiply mysteries.
But some traditions and thinkers start from the opposite end. What if consciousness isn't the thing that needs explaining? What if it's the ground everything else appears in? The positions differ in the details, but they share a reversal. Advaita Vedanta holds that pure awareness is the sole reality, and the material world is a kind of superimposition on it, something to be seen through. Kashmir Shaivism agrees that consciousness is fundamental but treats the world not as illusion but as expression, consciousness exploring its own creative power. The individual self isn't an error to be corrected but a real contraction of the whole, and liberation is recognition (pratyabhijñā): seeing through the contraction to the awareness that was never absent. The Yogacara school of Buddhism takes yet another angle: what we experience as an external world is the activity of mind itself; there is no material realm independent of cognition. And the contemporary philosopher Bernardo Kastrup, drawing on several of these traditions, makes a version of this argument through Western analytic methods. The physical world, he proposes, is what consciousness looks like from the outside, the way your brain activity on a scanner is just your experience seen from someone else's vantage point. On all these views, the hard problem dissolves, because there was never a second thing (matter) that needed to produce a first thing (experience).
Panpsychism†, which Pollan explores at some length, sits somewhere between these poles. It doesn't flip the frame entirely, but it does expand what matter is, adding experience to the basic inventory of the physical world alongside mass and charge. As Pollan notes, that's a big move, but then, two hundred years ago we didn't know about electromagnetism either.
None of these positions settles the question. But they change what the mystery is. If consciousness is produced by matter, the mystery is how the production works. If consciousness is fundamental, the mystery is why it appears, to itself, as a world in which it seems to be absent from most things. And if panpsychism is right, the mystery is how tiny sparks of experience combine into the unified awareness you're having right now.
The psychologist Daniel Gilbert† warns about "the desire for magic." Behind the word consciousness, he suggests, is an older word: soul. The mystery appeals to us partly because it preserves the possibility that something about us, some inner essence, some subjective spark, might transcend the physical, might survive. We may be protecting the mystery not because it's unsolvable but because we need it to be.
This doesn't mean the mystery is false. It means our relationship to it is not purely intellectual. The question of what consciousness is carries the weight of what we hope we are.