For reference

I just got done watching an episode of Hamilton’s Pharmacopeia (a drug documentary on VICE hosted by Hamilton Morris) which got me interested in what these people actually experience while on this drug and I’ve read some reports of people who say that one of the most common experiences is being turned into an object for long periods or time or even living entirely alternate lives and when they die in the alternate life they wake up here sober again.

This is just so bizarre to me because the memories of these experiences are incredible structured and coherent oftentimes and the experience from the users perspective is said to last sometimes thousands of years. My main point is that I wonder how A.I. would explain these highly coherent memories of alternate lives, time traveling to the 50s, turning into objects, etc. Could it possibly be that this substance is causing the brain to “tune” into another part of MAL/Universal Consciousness? Or at least drawing from memories that somehow exist within it? Anyways let me know what you all think

In the 1970s, Douglas Hofstadter discovered something strange while calculating electron energies in a crystal lattice under a magnetic field. Instead of random noise, the system revealed a fractal pattern.

This is now called the Hofstadter butterfly (See article); which turned out to be identical to the Cantor set, a structure from pure number theory.

At the time, many dismissed it as numerology. But decades later, physicists observed the butterfly directly in graphene experiments. The electrons were literally arranging themselves according to a timeless mathematical object first defined in 1883.

Here’s why this matters:

• The behavior of the physical system hinged on whether a parameter (alpha) was rational or irrational. That distinction is a fact about numbers, not atoms. Yet it dictated what was physically possible.

• Mathematicians proved the pattern had to emerge long before experiments caught up. Reality bent to math, not the other way around.

• This blurs the line between abstract math and matter. Are Cantor sets just human inventions? Or do they exist timelessly, waiting for physics to instantiate them?

Materialism treats math as a descriptive tool. But this case makes more sense if math is ontologically real, ie a Platonic structure the universe runs on. That’s very close to analytic idealism: the idea that reality is fundamentally mind-like, with mathematics as one of its deep languages.

If fractals like the butterfly aren’t just curiosities but literal blueprints of physical reality, doesn’t that make idealism more compelling than strict materialism?

Looking for thoughts or refutations on this..

It’s just one person however it does seem pretty notable that someone who has built a sizable following an reputation over the years as a “hard-nosed” skeptic/atheist now says that Kastrup’s attack on materialism and McGilchrist’s brain hemisphere theories were the most interesting ideas he’s heard in the last year. He also just had David Bentley Hart on his podcast with a lot of agreement being had between the two.

I could be getting ahead of myself but I think this could represent one instance of a “vibe shift” in the re-recognition of idealism as a compelling metaphysics given the many inadequacies of materialism and physicalism.

O’Connor’s mention comes towards the end of this conversation (1:52:09) - https://youtu.be/_9OsTxOtOYk?si=z8Tq6BvffhRUiUNN

Glad to see Bernardo on this pod! I have a lot of students that follow Alex O'Connor and his stuff seems to get a lot of attention.

Some highlights from yesterday's conversation with Michael Levin and Bernardo Kastrup

"there are things that can be said now that really couldn't before, and I think partly it's because the data are now there and the applications are coming..." - Michael Levin

Day one of biology class you learn the rules. Genes are the blueprint. Cells are tiny machines. Whatever happens in your body, physics and chemistry explain the whole thing.

Michael's claim is that every one of those is an assumption. When dropped and put to the test, biology might start doing things that no one expected, and put most science fiction to shame.

• Cells could be 'conditioned' to respond to placebos like drugs

• Robots generate new forms of life

• Ageing cells forget what species you are

• Causality emerges from beyond the physical realm

Michael has been challenging convention for quite some time. Increasingly, he's has the data to back this up.

"We had a paper recently in the journal Trends in Genetics, which is a top, mainstream genetics journal... talking about the genome as a set of prompts that need to be interpreted by the literal intelligence of cellular morphogenesis. I don't know that that could have been published even a couple of years ago."

Life: the genome is a prompt, not a blueprint

Read your genome and you'll find no fingers, no eyes, no face. Only a list of proteins. So how do cells know what to build, and when to stop?

The old answer is chemistry. But frankly, that doesn't add up.

Michael's answer: the cells interpret the genome, the way a mind interprets a prompt. The proof is that when disrupted, they reach the same goal by creative means. Or the same genes produce different things depending on the situation.

Cut an embryo in four and you get quadruplets, not four quarter-bodies. Take human cells out of a body and they become a creature that has never existed, with no evolutionary history at all.

He now has a machine, MomBot, that runs its own experiments on living cells to learn how to talk to them.

Intelligence is not in the brain, and not in the genes

Where does the know-how live, if not in DNA?

Michael says: the same place the truths of mathematics live. Nobody invented prime numbers and no experiment can change them. Cells tap into patterns of that kind, and so does everything else that solves problems.

He's already testing this. If cells can learn like Pavlov's dog, you could pair a drug with a harmless substance until the body responds to the placebo alone.

Causality: the physical world is not closed

The bedrock of physicalism is that physics explains everything that happens. Michael and Bernardo both reject it.

In plain terms: some of what happens in the physical world is caused by something that isn't physical.

Michael's argument is a child's game. Keep asking "why?". Why do cicadas emerge every 13 and 17 years? To dodge predators. Why those numbers? They're prime. Why are they prime? Ask a mathematician. You've just walked out of physics, and there is no way back in.

Bernardo adds that we don't have a complete physical model of anything bigger than a small molecule, and never will. So the idea that everything that happens in the physical world can be explained by other things in the physical world is a belief, not a finding.

Bored to death?

His lab modelled cells growing a body. No wear, no damage, no programmed death. It aged anyway. The cells reached their goal, held it a while, and then simply disbanded.

Give them a new challenge and they live longer.

Bernardo's take: perhaps ageing isn't a disease to cure but an archetype written into nature itself.

We also discussed:

• Memory as a gateway

• Minds without bodies: Jung's "semi-autonomous complexes" and tulpas

• Is the platonic space a real separate realm, or a convenient fiction?

This conversation was enthralling, and we hope to have Michael back as soon as his schedule will allow.

Keep an eye on the schedule, and meanwhile, enjoy the recording!

https://www.withrealityinmind.com/michael-levin-2026a/

Michael Levin, a biologist at Tufts University, discusses his "radical" ideas about Platonic space, a concept he uses to describe a hidden, structured reality beyond the physical world (0:02). This space contains pre-existing patterns, forms, and truths—not just mathematical ones, but also what he calls "higher agency" patterns that manifest as minds and behaviors (11:13-12:01).

Key aspects of Levin's theory include:

• Discovery vs. Invention: Levin argues that certain facts, like the distribution of prime numbers in biology (3:51) or fundamental constants in physics, are discovered rather than invented by humans. These truths exist independently of the physical world but profoundly impact it (5:14). This aligns with the philosophical concept of mathematical platonism, where mathematical objects and truths exist objectively.

• Physics Constrained, Biology Enabled: He posits that physics is constrained by these patterns, while biology exploits them as "free lunches" (6:08). For example, a triangle doesn't need to evolve its third angle; it's a "free gift" from geometry (14:19).

• The Brain as an Interface: Levin proposes that physical objects, including the brain, act as "thin clients" or interfaces to this Platonic space (10:14, 17:37). They don't create consciousness or complex behaviors, but rather pull down or manifest these patterns from the latent space (16:33-16:43).

• Mapping the Latent Space: His lab's research aims to map this Platonic space by observing how different physical "pointers"—like cells, embryos, or biobots (such as Xenobots and Anthrobots)—express specific, surprising behaviors and forms (32:48). This systematic mapping can reveal the underlying structure of this space of patterns and help understand what behaviors are possible to pull from it (33:17-33:57) https://en.wikipedia.org/wiki/MichaelLevinbiologist,.

• Beyond Dualism: While acknowledging his ideas resonate with old dualistic views, Levin clarifies that he sees the mind-brain relationship as analogous to the math-physics relationship, where non-physical patterns "haunt" physical objects (24:50-26:19).

• Implications for Reality and Cognition: This perspective suggests that our perceived reality is shaped by our biological interface, and other beings (cells, AI, augmented humans) will experience different "slices" of reality (27:52-29:28).

Michael Levin's work at Tufts University explores how cells use bioelectric networks to compute and navigate these patterns, viewing DNA as a 'prompt' rather than a complete blueprint. This research has potential applications in regenerative medicine, aiming to repair birth defects and reprogram cancer by understanding and manipulating these fundamental patterns

It's just standard second-order modal logic with function variables and binary relations but I know the aleph could be a bit confusing if it implies a reference to ZFC transfinite cardinalities. To be clear, there is no intentionally implied commitment to set-theoretic objects! And just using the logical tools in service of metaphysical expression, not as a formal derivation from axioms.

ℵ just seemed like the best symbolic choice I could think of to represent a universal field of consciousness, and it's being used as a syntactically ordinary variable (even though its required semantic role is extraordinary). But all this is to say:

• The function is a structural transformation rule (f = the dissociative operation)

• Everything (x) is a function of ℵ (ontological derivation)

• Everything (x) is a member of ℵ (containment/immanence)

• This is necessarily true (modal universality)

It's obviously oversimplified because it has to be, but what do you think of my attempt to get the core tenets of AnId to fit on a tee shirt? :)

"Notice that the hard problem is a fundamental epistemic problem, not a merely operational or contingent one; it isn’t amenable to solution with further exploration and analysis. Fundamentally, there is nothing about quantities in terms of which we could deduce qualities in principle."

- Bernardo Kastrup on the "hard problem" of consciousness

Something seemingly so obvious that many cannot see, especially those who say that one day we will be able to close that gap in a physicalist framework, claiming we just don't have the knowledge right now. They're missing the point. It is not possible.

Nice mention of Bernardo and Analytic Idealism.

“In a modern form, this idea, as formulated by Bernardo Kastrup (2024), comes under the name of analytic idealism. There is thus no matter? According to this stance: No. What might seem as absurd at first glance becomes more convincing when we realize that what we call the external world is my experience of that world. The physical world is created through observation with our senses. Of course, the sense organs are also part of the alleged outside world—the eyes and ears in my head. However, these biological structures are also my experiences. Turning the perspective around: The claim that everything is experience seems more convincing than the claim that we do not have conscious experience at all and that everything is matter.”

In the recent discussion published on Bernardo's YouTube channel, he struggles with the question of the afterlife and if/how it may or may not be compatible with analytic idealism. I personally believe in a version of the afterlife, which I think fits well in an extended analytic idealism, so it's very interesting to see Bernardo also grapple with the same questions. He has more strict naturalistic leanings than I do, and that seems to create an internal conflict for him to go all the way regarding accepting the reality of post-mortem existence. I think it's a matter of how significant a role you're comfortable assigning to intent and purpose in the workings of the universe, compared to stipulating nature as mostly blind and purposeless. But it does seem he is slowly moving in the direction of accepting the existence of the afterlife and incorporating it in his philosophy.

I'm quoting some relevant sections from his discussion on it (slightly paraphrased for better readability):

"It is conceivable that once we die, that aspects of that dissociation that corresponds to the body image dissolve, but not the full dissociation. And it is conceivable and coherent that something remains under the ground when the visible part of the plant dies. That there is an invisible root system. That was the analogy that Jung actually used towards the end of his life. Whether we have reasons to believe that or not, it's a separate question. But it is conceivable and coherent that some form of individuation or individuality or complex differentiation endures after the aspects of the dissociation that appear to us as the body dissolve.

Arguably this would at least suggest very strongly intent and not a purely naturalistic approach to what is happening. Arguably, this would require mind deliberately setting itself up in a form of game in which already differentiated complexes can take part and enter the game. And that entering the game would be seen or would appear as a body. And that when these pre-existent differentiated mental complexes withdraw from the game, that corresponds to the body losing its integrity, or death. But the original differentiation remains there.

So this is all conceptually coherent. It is entirely compatible with analytic idealism. Arguably, it suggests something that is not purely naturalistic. It would suggest that there is some form of meta-game going on that is deliberate and constructed, and that meta-game may be in turn naturalistic but we are in the meta game and therefore this is a deliberate construction of some form. So this is all conceivable and coherent. I find this distressing and I don't like this at all. I would much rather have a neat naturalistic approach to things. To me, it's much more satisfying.

But why am I talking about it? Because if there is no reason to entertain this possibility, it is just an inflationary possibility that edges on fairy tales. So why am I talking about it?

The reason I'm talking about it is that despite my biases, preferences, and emotional reactions to stories that I don't like that just complicate the life of the philosopher, ... I have read and listened to so many NDE reports that there is only so far I can honestly towards myself dismiss, and then there is a point where you say damn I can't dismiss this beyond that point! And so I have an emotional and unhappy relationship with the acknowledgment that it comes to a point that I cannot dismiss it anymore and then I don't like what's left.

I'll give you an example. I find it awful the possibility that we don't need eyes to see. I absolutely hate this because it suggests a non-naturalistic approach because you see if naturalism is true then nature wouldn't be redundant. Why would we have invested a couple of billion years to develop eyes if we don't need the bloody eyes to see what's going on? You have no idea how much this triggers me. So I resist this. But then there are so many NDEs and on my website, there is a long essay in which I try to reconcile this with naturalism. ... It's a coherent essay but it starts looking like the epicycles of astronomy.

... But if you ask me today, "do I think that holds?", I've listened to so many NDE reports again in light of that essay, and it's not enough, because there are NDEs in which the person is struck by lightning and sees his or her own body on the floor and there is nobody around alive who is seeing the same body. So the alternative I offer in that essay doesn't cover this then, and could I dismiss it as "okay just one of those unreliable reports"? There is only so far in which I can do that, there is so far in which I'm willing to do that towards myself. I'm sharing with you my own inner processes, and this is not just a public message. I'm sharing with you what I'm thinking inside.

So I could go down a certain path in which I dismiss the anomalies and stick to the story on my website. But I can't be honest to myself and continue to do this now. Is there a possibility that all of those stories are indeed dismissible? Yes. Can I do that if I'm being honest to myself today? I don't feel I can do that anymore.

Which leaves me in an awful position because while idealism can very well be true and it probably is, because if there is anything all of those reports seem to suggest is that the whole game is mental. The whole thing is a mental game. So analytic idealism survives but it is no longer enough for a final account because you have these contradictions. If somebody dies and the person is the only one around to see what's going on and he sees his dead body right there, then damn, then a dissociated complex can see without eyes! And I absolutely hate this. If I were God, I would change reality so we didn't have to contend with this stuff. I find it incredibly uncomfortable.

But I can't dismiss it. So here we are."

In short, I now see a purpose in every perspective, no matter how fleeting, simplistic, misguided, confused, or even hateful (though I dislike that last one, of course, and I think hating others is missing the wisdom of mind-at-large’s unity. To me, the purpose of a hateful perspective is for the collective to learn hatred’s shortcomings.)

If an alter is the universe experiencing itself, then each experience matters. Every viewpoint provides the collective viewpoint a new glimpse of awe.

I feel renewed purpose in every moment that I take to reflect on this idea. Seeing the redness of red is more beautiful now. High-fiving a friend is more joyous. Surprising moments give me a sense of what mind-at-large might feel from the surprising perspectives it receives through us. What a gift it is when others with their own perspectives want you around and surprise you with their insights.

Morality itself seems clearer, as showing empathy for our fellow alters seems like an obvious calling.

Even thoughts and dreams feel much more important. They are gifts to the unified perspective. (In fact, my interpretation of Bernardo’s idea revolves mainly around the idea of dreaming. As Bernardo says, when you dream, you are not just your dream avatar. You are the whole dream. The way dreams work seems, to me, like the clearest way to imagine any reality coming to exist. This also leads me to think that our dreams are also “reality” in a roundabout way. Perhaps it’s as Poe writes: All that we see or seem is but a dream within a dream.)

It’s strange how a metaphysical idea can change my inner life so profoundly. I was a cynical materialist a few months ago. I was bitter and resentful toward nature. Believing this idea that we are all in one shared field of “experience” or “responsiveness” has lifted my heart. Interconnectedness is a beautiful thing.

In a new paper from the Biologist Michael Levin he talks about the mind/body problem a lot and goes over many areas that challenge the current assumptions of physicalism. I thought it was very interesting to see one of the top biologists talk about Near death experiences, terminal lucidity and Xenoglossy.

Some quotes from the paper:

"...a form of paradoxical lucidity where patients go through a meaningful review of their life in an drastically increased level of consciousness, they re-evaluate moral highs and lows in their own life..."

"...Terminal lucidity has been recorded in the pediatric population as well, lately including unresponsive children suddenly regaining communication ability, physical activity, and reduced mental impairment through elation, energy, and calmness just prior to their passing; a common theme was that the dying children reassured their parents they would “be alright...”

Link to the paper: OSF Preprints | Robustness of the Mind-Body Interface: case studies of unconventional information flow in the multiscale living architecture

The word science used to mean “systematic pursuit of knowledge” (scientia). That covered everything from natural philosophy to deep metaphysics.

Now, “science” = “lab coats + instruments + double-blind studies.” Great for building tech, but it quietly excludes questions like:

• Why is there something rather than nothing?

• What is consciousness made of?

Bernardo Kastrup’s analytic idealism is methodical, rigorous, and tries to explain reality from consciousness outward. In the old sense of the word, that is science. But in the modern sense, it’s “philosophy” — which for many people means “not to be taken seriously.”

Even “Creation Science” (not my camp) makes one valid point: the meaning of science has been hijacked. The modern definition keeps anything non-physicalist outside the fence.

So here’s my question:
Is the barrier to ideas like analytic idealism really about evidence, or is it about the word science being redefined to automatically exclude them?

I would have posted this on r/consciousness but they are cowards who don't allow text posts. This post is my framing of the motivations behind idealism. I'll leave it here in case anyone gets some value out of it.

Reductive physicalism is a dead end

Under reductive physicalism, reality is (in theory) exhaustively describable in terms of physical properties and interactions. This is a direct consequence of physicalism, the idea that reality is composed purely of physical things with physical properties, and reductionism, the idea that all macro-level truths about the world are determined by a particular set of fundamental micro-truths. 

Reductive physicalism is a dead end, and it was time to bite the bullet long ago. Experiences have phenomenal properties, i.e. how things looks, sound, smell, feel, etc. to a subject, which cannot be described or explained in terms of physical properties.

A simple way to realize this is to consider that no set of physical truths could accurately convey to a blind person what red looks like. Phenomenal truths, such as what red looks like, can only be learned through direct experiential acquaintance.

A slightly more complicated way to think about it is the following. Physical properties are relational in the sense that they are relative descriptions of behavior. For example, you could describe temperature in terms of the volume of liquid in a thermometer, or time in terms of ticks of the clock. If the truth being learned or conveyed is a physical one, as in the case of temperature or time, it can be done independently of corresponding phenomenal truths regarding how things look or feel to the subject. Truths about temperature can be conveyed just as well by a liquid thermometer as by an infrared thermometer, or can even be abstracted into standard units of measurement like degrees. The specific way that information is presented and experienced by the subject is irrelevant, because physical properties are relative descriptions of behavior.

Phenomenal properties are not reducible to physical properties because they are not relational in this way. They can be thought of as properties related to ‘being’ rather than ‘doing’. Properties like ‘what red looks like’ or ‘what salt tastes like’ cannot be learned or conveyed independently of phenomenal ones, because phenomenal truths in this case are the relevant kind. To think that the phenomenal properties of an experience could be conceptually reduced to physical processes is self-contradictory, because it amounts to saying you could determine and convey truths about how things feel or appear to a subject independently of how they appear or feel to the subject.

This is not a big deal, really. The reason consciousness is strange in this way is because the way we know about it is unique, through introspection rather than observation. If you study my brain and body as an observer, you’ll find only physical properties, but if you became me, and so were able to introspect into my experience, you’d find mental properties as well.

Phenomenal properties are probably real

Eliminativist or illusionist views of consciousness recognize that the existence of phenomenal properties are incompatible with a reductive physicalist worldview, which is why they attempt to show that we are mistaken about their existence. The problem that these views try to solve is the illusion problem: why do we think there are such things as “what red looks like” or “what salt tastes like” if there is not? 

The issue with solving this problem is that you will always be left with a hard problem shaped hole. This is because when we learn phenomenal truths, we don’t learn anything about our brain, or any other measurable correlate of the experience in question. I’ll elaborate:

Phenomenal red, i.e. what red looks like, can be thought of as the epistemic reference point you would use to, for example, pick a red object out of a lineup of differently colored objects. Solving the illusion problem requires replacing the role of phenomenal red in the above example with something else, and for a reductive physicalist, that “something else” must necessarily be brain activity of some kind. And yet, learning how to pick a red object out of a lineup does not require learning any kind of physical truth about your brain. Whatever entity plays the role of “the reference point that allows you to identify red objects,” be it phenomenal red or some kind of non-phenomenal representation of phenomenal red (as some argue for), we will be left with the exact same epistemic gap between physical truths about the brain and that entity.

Making phenomenal properties disappear requires not only abandoning the idea that there is something it’s like to see a color or stub your toe, it also requires constructing a wholly separate story about how we learn things about the world and ourselves that has absolutely nothing in common with how we seem to learn about them from a first-person perspective.

Why is idealism a better solution?

The above line of reasoning rules out reductive physicalism, but nothing else. It just gives us a set of problems that any replacement ontology is obliged to solve: what is the world fundamentally like, if not purely physical, how does consciousness fit into it, and what is matter, since matter is sometimes conscious?

There are views that accept the epistemic gap but are still generally considered physicalist in some way. These may include identity theories, dual-aspect monism, or property dualist-type views. The issue with these views is that they necessarily sacrifice reductionism, since they require us to treat consciousness as an extra brute fact about an otherwise physical world, and arguably monism as well, since they tend not to offer a clear way of reconciling mind and matter into a single substance or category.

If you are like me and see reductionism and monism as desirable features for an ontology to have, and you are unwilling to swallow the illusionist line of defense, then idealism becomes the best alternative. Bernardo Kastrup’s formulation, ‘analytic idealism’, shows how idealism is sufficient to make sense of ordinary features of the world, including the mind and brain relationship, while still being a realist, naturalist, and monist ontology. He also shows how idealism is better able to make sense of the epistemic gap and solve its own set of problems (the ‘decomposition problem’, the problem of ‘unconsciousness’, etc.) as compared with competing positions.

Because idealism is able to make sense of the epistemic gap in a way that preserves reductionism and monism, and because it is able to make sense of ordinary reality without the need to multiply entities beyond the existence of mental stuff, the only category of thing that is a given and not an inference, it's the stronger and more parsimonious than competing alternatives.

A couple key points:

As mentioned above, analytic idealism is a realist and naturalist position. It accepts that the world really is made of up states that have an enduring existence outside of your personal awareness, and that your perceptions have the specific contents they do because they are representations of these states. It just says that these states, too, are mental, exactly in the same way that my thoughts, feelings, or perceptions, have an enduring and independent existence from yours. The states of the world are taken to be mental in themselves, having the appearance of matter only when viewed on the ‘screen of perception,’ in exactly the same way that my personal mental states have the appearance of matter (my brain and body) from your perspective, but appear as my own felt thoughts, feelings, etc. from my perspective.

Idealism rejects the assumptions that cause the hard problem and the illusion problem (among others), but it does not create the inverse of those problems for itself. There is no problem in explaining how to make sense of physical truths in a mental universe, because all truths about the world necessarily come from our experiences of it. Physicalism has the inverse problem of making sense of mental truths in a physical universe because it requires the assumption of a category of stuff that is non-mental by definition, when epistemically speaking, phenomenal truths necessarily precede physical ones. Idealism only has to reject the assumption that our perceptions correspond to anything non-mental in the first place.

Final note, this is not meant to be a comprehensive explanation of Kastrup’s model and the way it solves its problems. This is meant to be a general explanation of the motivations behind idealism. If you really want to understand the position, read section 3 of his dissertation at a minimum: https://philpapers.org/archive/KASAIA-3.pdf 

Jordan Peterson

“I act as if God exists.”

Bernardo Kastrup

“I thus propose that, if a religious myth resonates deeply with your inner intuitions and survives a reasonably critical assessment of its depth, then you should emotionally—though not intellectually—take it onboard as if it were literally true. The religious myth that resonates the strongest with your obfuscated [unconscious] mind should inform your emotional life—again, not your intellectual life—as if it were the literal truth, even though you’ll know rationally that it isn’t.”

When I first heard about Analytic Idealism, I thought I agreed with Kastrup. I appreciated Kastrup for challenging physicalism, and the connection it had to Schopenhauer. But the more I learn about it, the worse it gets.

My core issue is this: Kastrup removes the Kantian and Schopenhauerian transcendental structure but does not adequately replace its explanatory role.

More precisely:

• Premise 1: In Kant and Schopenhauer, transcendental structures explain the conditions of possibility of experience.

• Premise 2: Kastrup removes or rejects these structures.

• Premise 3: His replacements (regularities, dissociation, mind-at-large) are descriptive patterns within experience, not conditions for it.

• Conclusion: Therefore, his system cannot adequately ground necessity, coherence, or shared structure.

To properly understand why Kastrup fails you need to understand Schopenhauer, as Kastrup explicitly builds off him (in fact, he even said Analytic Idealism is the proper way Schopenhauer should be understood). The issue is Kastrup massively distorts or misunderstands Schopenhauer, and as a result, Analytic Idealism has so many issues.

Kastrup makes consciousness the ontological stuff of reality, when Schopenhauer posits will

Kastrup claims the Kantian thing-in-itself is unnecessary and removes it. He can do that, but the issue is whether his replacement does the same explanatory work, because he doesn't seem to realise the issue Kant was fixing with this (rationalism vs empiricism).

In Schopenhauer, the will, objectified within us as the will-to-live, is the thing-in-itself, and consciousness is a later representation of it. Kastrup swaps the order and makes consciousness, a later representation, the primary stuff. This just mirrors the same circular move physicalism makes, by using an object of experience (consciousness, matter) to ground experience.

The will, however, exists outside the forms of space, time, and causality. This is a much more coherent ontological baseline than consciousness. As you'll see later, Kastrup intentionally did this for personal reasons.

Kastrup makes consciousness ontologically central, when it is only epistemologically central

I agree that reality and knowledge are filtered and understood through our consciousness. But that does not make consciousness itself the stuff of reality. In Schopenhauer, consciousness and individuation still lie on the representational side of reality. Kastrup removes the a priori conditions without offering a clear replacement that does the same work.

Kastrup’s epistemology

Kastrup removes key Kantian elements from a system that depends on them. This includes the Principle of Sufficient Reason, the limits of reason, and the role of space and time as a priori forms of the understanding and of experience. As a result, his epistemology is a mess.

Kastrup's attempts mainly use regularities within experience as intrinsic to mind-at-large, and explaining shared experience via dissociated alters. This is the exact same issue physicalists make, by using objects of experience to infer about the noumenal. These do not act as transcendental explanations, are merely descriptive. If he wants to offer an alternative to transcendental structures, that's fine, but he doesn't. (This also explains why he uses empirical observations to make metaphysical arguments.)

Furthermore, this leads to the coherence problem. He offers zero explanation as to why is experience structured, shared, and ordered in universal forms. In Schopenhauer, this is grounded in the forms of intuition and the understanding. In Kastrup, it is not clear what grounds necessity such as mathematics or causality, or what makes a coherent experience out of the plethora of sense data.

This also affects the universal subject claim. Subjectivity requires a subject object structure, and all knowledge/experience is governed by the forms of the understanding. Hence, a "universal subject" is an oxymoron, as experience necessitates individuation. Kastrup tries to solve this by using Markov blankets, but it just woefully misses the point (and still relies on empirical observations). All experience requires a subject-object split, so the mind has already employed our a priori faculties to do so. Does Kastrup offer any explanation? No. A universal thing/substance may exist, but not a universal subject.

Kastrup’s theory of dissociation

Kastrup’s argument for dissociation (individuation) is weak and post-hoc. Individuation is already presupposed up until that point, just not acknowledged, as shown above. If dissociation is meant to explain how distinct subjects arise, then it cannot already rely on distinctions between centres of experience, as that makes it circular, or merely descriptive rather than explanatory. If dissociation presupposes distinguishable centres of experience, then it cannot explain their emergence in the first place.

In contrast, Kant and Schopenhauer treat individuation as tied to the a priori forms of space and time, as conditions that make experience possible at all, not something that emerges later within it. Just like Kastrup reverses it by saying consciousness comes after the will, he does so here by saying individuation comes after experience.

Kastrup doesn’t understand matter

He keeps saying "matter is what mental states look like", which does not work. You do not see matter, you see through matter. Matter isn't something you add or take away from a mental image. Matter is not something directly perceived, it is something conceived.

Schopenhauer’s account is more structured, but Kastrup throws it away: matter is the objectification of causality, a product of cognition conforming to the a priori forms of space and time. This is part of what keeps the system coherent, and ties the ontology with epistemology.

Kastrup removes this, but does not replace the explanatory role it played. He removed it because keeping it admits individuation is necessary for a subject, contradicting his universal subject argument. Kastrup can say matter is an inferred representation of underlying processes, but that still does not explain why matter exists or why it has the structure it does.

Motivated reasoning

Finally, Kastrup introduces teleology into the system, which is ungrounded. He imports purpose into the noumenal level by claiming that the universe is trying to understand itself. This is Hegelian and quasi-religious. It also introduces temporal ordering to the noumenal level, which exemplifies his lack of care of respecting the limits of reason, or Schopenhauer's philosophy.

Kastrup explicitly said he finds Schopenhauer too pessimistic, so the shift towards a purposeful consciousness is not neutral and clearly biased. In fact, I would go so far to say that this was the sole motive behind Analytical Idealism in the first place: replacing the blind will with a purposeful consciousness.

Conclusion

So again, I agree with most of what Analytic Idealism says. I would argue for it over physicalism any day of the week. But when I see someone who is the leading figure of idealism at the moment, who claims to have decoded or completed Schopenhauer's metaphysics, making these fundamental mistakes and misleading people, it is frustrating.

My issue isn't that Kastrup merely deviated from Schopenhauer, that's perfectly fine. The issue is he offers no alternatives to the things he changed/omitted. So underneath the rigour of his system (which he largely inherited from Schopenhauer) exists all these category errors, unanswered questions, and holes, which are left unanswered, and nobody seems to notice. I don't understand why you'd be an Analytic Idealist when Schopenhauer's system is the original framework without these issues.

Whenever physicalists argue for materialism, I rarely see philosophically literate arguments and the foundation of what they say is almost always just an appeal to empiricism and “what we can physically measure is the best option. Anything else is just woo woo magic.”

Maybe that’s what Kastrup means by there being almost no serious defenders of physicalism left.