by This essay completes a sequence. The first article considered Iain McGilchrist’s panpsychist proposal that matter is a phase of consciousness, the way ice and vapor are phases of water. Its companion examined Daniel Dennett’s illusionism, which argued that consciousness as we ordinarily conceive it is a user illusion the brain stages for itself. The third position, the one we take up here, inverts the relation again. Bernardo Kastrup’s analytic idealism holds that matter is an appearance within mind rather than the substance from which mind emerges or the surface on which it plays. The three views together cover most of the contemporary terrain on the consciousness question, and once we have all three on the table we can ask what each gets right, what each fails to deliver, and what the overall topography tells us about the limits of philosophical argument when applied to the deepest question we know how to ask.
Kastrup is an unusual figure in contemporary philosophy of mind. Born in Rio de Janeiro in 1974 and now based in the Netherlands, he holds two doctorates: one in computer engineering from Eindhoven University of Technology, completed in 2001, and a second in philosophy from Radboud University Nijmegen, completed in 2019, with a dissertation titled “Analytic Idealism: A Consciousness-Only Ontology.” He spent years at CERN working on the trigger system for the ATLAS experiment at the Large Hadron Collider, founded the parallel processor company Silicon Hive (acquired by Intel in 2011), and currently runs an AI hardware company called Euclyd while serving as Executive Director of the Essentia Foundation, the Dutch nonprofit dedicated to advancing post-materialist research. His scientific credentials matter for the discussion that follows, since one common line of dismissal against idealism is that it represents a flight from science. Kastrup spent two decades inside science before publishing a single book on metaphysics, and the work he produces shows that experience on every page.
Begin with the position itself, stated as carefully as possible. Analytic idealism holds that reality is mental at its base. There is one substrate of existence, and that substrate is consciousness, what Kastrup calls mind-at-large or the universal field of subjectivity. The physical world we perceive is the extrinsic appearance of mental processes, in the way that the surface activity of a brain (neurons firing, blood flowing, electrical signals traveling) is the extrinsic appearance of someone’s inner experience. When you observe another person’s brain in an MRI scanner, you see the outside of their thoughts. When you look at the universe, you see the outside of mind-at-large.
The question this position must answer is the obvious one. If everything is mind, why does it look like a world of separate things, including separate persons with separate inner lives? Kastrup’s answer is the most striking move in his system. He argues that individual minds are dissociated alters of universal consciousness, comparable to the alternate personalities that appear in cases of Dissociative Identity Disorder, the condition formerly known as multiple personality disorder. In DID, one biological organism hosts multiple distinct centers of awareness that often have no access to one another’s memories, preferences, or self-conception. Each alter experiences itself as a separate person. Each alter is a real conscious subject. There is one underlying organism producing all of them. Kastrup proposes that we (and all other living creatures) are alters of mind-at-large, dissociated centers of awareness within the single field of universal subjectivity, each of us mistakenly experiencing ourselves as a separate person when we are something the universe is temporarily doing.
The physical world, on this view, is a representation. Specifically, it is what the dissociation looks like from the inside of an alter. Just as the dashboard of an airplane represents external states (altitude, fuel, airspeed) without itself being those states, our perceived world represents the activity of mind-at-large without itself being that activity. The dashboard analogy, which Kastrup uses repeatedly, makes the claim concrete. We do not perceive reality directly. We perceive a user interface that represents reality, and the interface is constructed by our cognitive apparatus, which is itself a dissociative boundary within a larger mental field.
Several consequences follow that distinguish analytic idealism from neighboring positions. Death, on this account, is the end of dissociation rather than the end of consciousness. When the alter dissolves, what was alter rejoins what was always already mind-at-large. Psychedelics are interpreted as substances that weaken the dissociative boundary, which is why they often produce ego dissolution and what Kastrup considers genuine glimpses of pre-dissociated awareness. Near-death experiences are read as moments when the dissociation thins and richer experience floods through. Most strikingly, artificial intelligence on Kastrup’s view cannot be conscious in the relevant sense, because computers are what he calls heaps, aggregates of components that do not constitute a true dissociative process. Only metabolism, life, the actual process of biological self-maintenance, produces the kind of dissociation that yields a conscious alter. Silicon will not do, no matter how complex the architecture.
Where his case works, it works for these reasons.
The argument is effective because idealism dissolves the hard problem rather than postponing it. If consciousness is the base substrate and matter is its appearance, there is no question of how non-conscious stuff produces conscious experience, since there is no non-conscious stuff. The question David Chalmers identified in 1995, the question that materialism cannot answer and that illusionism tries to argue out of existence, simply does not arise on idealist premises. This is no small advantage. A theory that does not face the hardest problem in philosophy of mind has gained considerable ground over theories that do.
It is also effective because the DID analogy is rooted in actual psychiatric and neurological evidence. DID is a controversial diagnosis, but its empirical reality is harder to dispute than its theoretical interpretation. There exist documented cases of patients whose alters present with measurably different physiological responses, different visual capabilities (one alter cortically blind while another sees normally, as documented by Strasburger and Waldvogel in their 2015 PsyCh Journal case report on patient B.T., who showed completely absent visual evoked potentials in her blind alters and normal VEPs in her sighted ones, with switches occurring within seconds), and different allergic reactions, all in the same body. Whatever DID is, it shows that the relationship between one biological substrate and multiple centers of awareness is genuinely possible. Kastrup uses this as proof of concept rather than as proof of his metaphysics, but the proof of concept matters: a critic cannot dismiss the dissociation move as impossible in principle, because we have evidence that something analogous happens at the human scale.
A further strength: the position takes empirical findings about brain function seriously in a way his critics often do not credit. Studies by Robin Carhart-Harris and colleagues at Imperial College London, beginning with the 2012 Proceedings of the National Academy of Sciences paper on psilocybin and brain activity, found that psychedelic experience correlates with decreased activity in certain brain regions, particularly the default mode network. Materialist orthodoxy predicts that richer experience should require more brain activity. The data show the opposite in significant cases. Kastrup uses this as evidence for what philosophers call the brain-as-filter hypothesis: the brain constrains and channels consciousness rather than producing it, with reduced activity allowing wider awareness through. Aldous Huxley made a version of this argument in 1954 in The Doors of Perception, drawing on Henri Bergson’s earlier work, and the recent neuroscientific findings have given the older idea a second life. Whether or not one accepts the idealist conclusion, the empirical pattern is real and demands explanation.
The position earns additional power because it accommodates findings in foundational physics that materialism handles awkwardly. The relational interpretation of quantum mechanics, developed by Carlo Rovelli starting in 1996, holds that the properties of a physical system exist only relative to other systems, with no observer-independent reality. Kastrup, in a 2018 Foundations of Physics paper coauthored with Edward F. Kelly and others, argued that this interpretation aligns naturally with idealism, since a universe in which physical properties exist only as relations is a universe whose deepest substrate may be mental rather than material. The argument does not prove idealism, though it does show that idealism coordinates with serious physics in ways that flat-footed materialism does not.
Last, the position is internally coherent in a way panpsychism struggles to achieve. McGilchrist must explain how micro-experiences combine into the unified field of human awareness, and the combination problem identified by William Seager in 1995 has no settled solution. Kastrup argues that idealism faces only the inverse problem, what philosophers call decombination, which asks how universal consciousness divides into apparent multiplicity. Kastrup’s answer is dissociation, and dissociation is something we have empirical reason to believe occurs in nature. The combination problem requires us to imagine micro-experiences merging into macro-experiences, a process for which we have no empirical model whatsoever. Decombination, by contrast, has a real-world analog in psychiatric phenomena that can be studied. The asymmetry between the two problems is one of Kastrup’s strongest arguments for preferring idealism over panpsychism.
Weaknesses follow, however, and any honest reader should press them.
The argument is not effective because the DID analogy, suggestive as it sounds, is doing more work than analogies can legitimately bear. Even if dissociation occurs in human minds, extrapolating from human dissociation to cosmic dissociation is a major leap that the analogy cannot underwrite by itself. Kastrup acknowledges this and frames the move as inference to the best explanation, but inference to the best explanation requires that the explanation actually be best, which is the question in dispute. A critic can reasonably reply that we have no idea whether mind-at-large, even if it exists, would dissociate the way human minds do, since the conditions producing human dissociation (trauma, neurological development, psychological defense) have no obvious analog at cosmic scale.
It is also not effective because DID itself remains contested as a clinical diagnosis. The condition was popularized by cases like Sybil and The Three Faces of Eve, both of which have been challenged in subsequent decades on grounds of iatrogenic creation, where the diagnosis was effectively constructed by therapist suggestion rather than discovered in the patient. The 1973 Sybil case, the foundational case for the modern diagnosis, was substantially reexamined by Debbie Nathan in her 2011 investigation Sybil Exposed, which presented evidence that the alters were largely produced by the therapeutic process rather than preexisting it. Building a metaphysics on a clinical category whose status is genuinely uncertain creates exposure that Kastrup tends to underplay. The cases of differential physiological response across alters are real and significant, but the broader diagnostic category of DID may not be quite the natural kind his argument requires.
A further weakness: the decombination problem may be no easier than the combination problem, only different. Kastrup claims it is easier because we have human dissociation as an example. The reply is that dissociation in human minds occurs within a single biological organism with a single nervous system, where the unity is given and the division is what needs explanation. Dissociation at cosmic scale would require the unity to fracture across what looks like an entire universe of separate beings, which is a different operation by orders of magnitude. Saying “the universe dissociates the way a human mind dissociates” makes the words available without making the operation clear. Whether this is genuine progress over panpsychism depends on whether the analogy translates, and that translation has not been demonstrated.
The position fails because it cannot account well for the resistance the world offers to the will. If everything is mind, why does the chair refuse to move when I will it to? Why do facts about the world repeatedly disconfirm my expectations? Kastrup answers that the rest of mind-at-large is not under my control, since I am only an alter, and what I experience as physical resistance is the appearance of mental activity outside my dissociative boundary. This response is not incoherent, but it does shift the burden onto explaining why the appearance is so consistent across different observers, why it has the lawful structure physics describes, and why it tracks counterfactuals so reliably. A mind-at-large that produces a perfectly consistent appearance of a physical world is doing something hard to distinguish from actually being a physical world, and the explanatory virtue of idealism shrinks the more its appearance matches what materialism predicts.
His treatment of artificial intelligence is also vulnerable to challenge. The claim that silicon cannot host consciousness because it is a heap rather than a metabolic process is a strong commitment that does work Kastrup may not be able to cash. The distinction between heap and life is doing the heavy lifting, and the distinction is itself empirical: he is claiming, on metaphysical grounds, that we know which natural systems can support dissociation and which cannot, but the criterion (metabolism) is itself something that arose through unguided physical processes. Why metabolism in particular should mark the threshold of dissociative capacity, when we cannot specify what about metabolism makes it special, leaves the position exposed to the objection that the threshold is being drawn for convenience rather than on principle. If materialism cannot explain why neurons matter and silicon does not, idealism inherits the same difficulty in different vocabulary.
Last, idealism shares with all consciousness-fundamental positions the difficulty of empirical falsifiability. Kastrup makes empirical predictions about psychedelics, about NDEs, about quantum measurement, but the core claim that reality is mental rather than physical is hard to test in any decisive way, since both views can typically accommodate the same data with different interpretations. While this does not prove idealism wrong, it does mean that any preference for idealism over materialism rests on theoretical virtues like coherence and explanatory parsimony rather than on a knockdown empirical case, and theoretical virtues alone rarely settle metaphysical disputes that have run for two and a half thousand years.
Now bring the three positions together. Each of the views we have considered confronts the hard problem differently, and each pays a different price for its solution.
Dennett’s illusionism tries to make the hard problem disappear by denying that phenomenal consciousness exists in the way introspection suggests. The cost is high. Illusion presupposes a perceiver, and the position has never quite recovered from this objection. What survives Dennett’s project is a sharpened understanding of how introspection misrepresents underlying neural activity, which is significant cognitive science but does not amount to the metaphysical achievement he claimed.
McGilchrist’s panpsychism tries to dissolve the hard problem by making consciousness elementary at every level of organization, with matter as one of its phases. The cost is the combination problem, which has occupied serious philosophers since William James raised the worry in 1890 and which has not been answered to general satisfaction. What survives the panpsychist program is the recognition that emergent materialism may be smuggling in a miracle when it claims that consciousness arises from non-conscious matter at some unspecified threshold of complexity.
Kastrup’s analytic idealism tries to dissolve the hard problem by making consciousness the only thing there is, with matter as its appearance under conditions of dissociation. The cost is the decombination problem, the dependence on a contested clinical analogy, and the difficulty of explaining the apparent independence of physical regularity from subjective will. What survives the idealist position is a coherent and rigorous alternative to materialism that takes the empirical findings about psychedelics, NDEs, and foundational physics more seriously than its competitors typically do.
The honest verdict is that none of the three positions has solved the consciousness problem, and that each has identified real difficulties in the others. If those previous moves are correct, then the hard problem is real (against Dennett), the materialist emergence story is unconvincing (against the orthodoxy), and consciousness must be either elementary at every level (McGilchrist) or the only level (Kastrup). The choice between the latter two depends on whether one finds the combination problem or the decombination problem more tractable, and reasonable readers will divide on that question along lines that have less to do with evidence than with which kind of mystery each finds easier to live with.
What the trilogy together suggests is something philosophy is reluctant to admit. The consciousness problem may not be solvable by argument alone. We are conscious beings trying to construct a theory of consciousness from inside consciousness, and there is no obvious way to step outside the medium in which the theorizing takes place. McGilchrist and Dennett and Kastrup have each produced careful work that engages the problem from a different angle, and each has been pressed by serious critics in ways that expose real weaknesses in his position. None of the three has won the argument. None has even come close to winning the argument. What they have done, taken together, is mapped the terrain in enough detail that we can now see why winning the argument may not be possible with the tools currently available.
This map is itself an honest accounting of the limits of the inquiry, which philosophy at its best produces and which the consciousness debate increasingly demonstrates. The next generation of work in this area will need to go beyond the choice among materialism, panpsychism, illusionism, and idealism, and find some way of asking the question that the current frame cannot accommodate. Whether that requires a new conceptual vocabulary, a new empirical paradigm, or simply more patience with the irreducibility of the problem remains to be seen.
For the BolesBlogs reader who has followed the sequence to this point, the takeaway is this. Consciousness is real. The hard problem is real. Materialism cannot explain consciousness. Panpsychism faces the combination problem. Illusionism collapses on its own premises. Idealism trades one set of difficulties for another. We have not been told the truth about what we are by any of the available frameworks, and the search continues. The task of the serious reader is to hold the question open, refuse to settle prematurely on any of the offered solutions, and continue reading what the philosophers and the scientists and the contemplatives produce as they work toward whatever lies beyond the current map.
Kastrup wrote in a 2019 Scientific American opinion piece that mind is the only carpet under which we can no longer sweep the inconvenience of consciousness. The line is sharp and works whether or not we accept his particular formulation of what mind requires us to believe. Consciousness is the inconvenience that materialism cannot explain. Whether it is the only inconvenience, or whether it is the substrate from which all other inconveniences follow, is the question we have been asking for three articles now, and the question we will keep asking long after this sequence concludes.
We assume our own inwardness because we have nothing else to assume from. Whether that inwardness reaches outward into a world of separate things, downward into the smallest particles, inward into a single field that contains everything, or only inward into the lighted corner where we happen to find ourselves, is the question philosophy has not yet answered and may never answer. The honest scholar lives with this. An honest writer says it out loud. And the honest reader, having followed three serious philosophers through three serious wagers, walks away from the sequence with sharper questions and fewer false certainties than when he or she began.
That is what philosophy at its best can do for us. None of the three thinkers we have considered solved the problem. All three of them taught us how the problem must be approached if we are to make progress on it, and all three of them deserve continued reading, continued argument, and continued respect for the seriousness with which they pursued the deepest question we have.
Part three of three. For the full sequence and reading guide, see The Consciousness Trilogy: Reading Three Wagers on the Question We Cannot Settle.
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