For now I have one specific question. I’m reading Bernardo Kastrup’s “Why materialism is baloney”. I’ve watched his videos, and am familiar with his ideas. I’m just confused about a part of the book i ran into. In the chapter he’s pointing out the absurd implications of materialism, one of them being that we hallucinate reality - that under materialistic views, our brain creates images of the external reality, which we can’t have direct access to. He claims this is absurd. I thought this was proven scientifically? Can’t we observe photons reaching our eyes, and see the brain computing images with brain scans? What am I missing here?

  • An interesting question. It would help if you could add an extended quote or two. Mar 6, 2022 at 0:25
  • “When one carefully looks at the implications of materialist metaphysics, it doesn’t look intuitive at all. It denies the reality of immediate experience and postulates it all to br a “hallucination” taking place entirely within our heads. It denies that we can ever directly access the “outside” world. It states that the stars we see in the night sky are all inside our skulls”. The next chapter (which I just started) talks about neuroscience, so maybe I’ll find my answer there. At the moment, he’s saying that neuroscience is vague and cannot explain things precisely. Mar 6, 2022 at 0:54
  • 3
    Although the question is interesting, I really don't understand Kastrup's argument here. What is absurd? After all, phenomenology has been a widely discussed topic involving numerous philosophers (Kant, Heidegger...). To simply dismiss it as absurd is kind of presumptuous, and to be honest he can't ignore it, so it looks like he is counting on the ignorance of his readers so that they don't realize his position is not as clear cut as he wants it to be. Looks like he is confusing "I don't like this idea" with "this idea is absurd".
    – armand
    Mar 7, 2022 at 1:39

2 Answers 2


To understand his point, you have to understand what Kastrup is basing it on, so let me try to explain that. In this answer I describe the position that Kastrup is thinking of. You will note that according to this viewpoint--which is the default scientific world view--there is a universe out there, but we have no direct observation of it. Even fundamental things like our experience of space are constructed by our brains from data that is provided by the nervous system. In other words, the way we visualize space is in our head, not out in the world.

According to this view, we can have no idea what the world outside our head is really like. Imagine a situation like in the movie, "the Matrix" where the entire world is generated by computers. But there is no reason to think that the world that the computers exist in is dramatically different from the generated world. Maybe Neo isn't a human being at all. Maybe he's a jellyfish-like creature.

But even that is too generous. Maybe the real underlying universe is nothing like our universe at all, even to the point where there is no space, no matter, no time, no physical causality. Maybe we are just disembodied spirits dreaming of a world of space, matter, time, and causality. In fact, Kastrup himself believes the real underlying world is just one mind (not a brain!) divided into parts that don't know they are all parts of a whole.

So, given that we can't rule out Kastrup's view by observation and experience, if you continue to insist that even though you can't know that the real world is anything like what you experience, yet you insist it is pretty much just like what you experience, then what you are in effect claiming is that you are a real physical person with a real physical brain, whose view of the world is entirely generated within your brain. That is, the universe that you experience is entirely within your skull. Kastrup finds this hypothesis absurd.

So now on to the question: how does he deal with neuroscience? First of all, let me note that neuroscience is just more of the world that is constructed inside our heads. That is, our experience of brains and instruments is also all inside our skulls, so the findings of neuroscience can't invalidate the general absurdity that Kastrup sees.

However, Kastrup believes that our physical bodies are constructed by a universal mind, so why does this universal mind create such a complex illusory path from the real world to the mind? Where does all of this complexity come from? I believe Kastrup would say that the universal mind presents us with a view of the world that is decidedly mechanical, with ever increasing detail as you look more closely at it. Neuroscience is no more of a puzzle than organic chemistry or subatomic physics. It is just the nature of the complex world constructed by the universal mind.

  • It's wrong to say that Kastrup believes our physical bodies are "constructed" by a universal mind. He believes our physical bodies are part of a universal mind. His view is that everything we normally consider physical has real existence, only it isn't physical, it's all a mental substance that has experiences and is part of a single mind.
    – causative
    Mar 7, 2022 at 16:01

From a look around Kastrup's website, he doesn't deny that neurons and other physical things exist and operate as physicists say they do. He doesn't think the whole notion of neuroscience is something imaginary, and he does think that there is a relationship between what's going on in the brain and what's going on in your mind. He might say there "is really no brain," that it's all mind, but it's a mind that's functionally equivalent to the brain.

For example, this quote by Kastrup: "An elementary subatomic particle is a particular pattern of excitation of a quantum field. That quantum field, that thing, although it’s entirely abstract, it exists." The quote demonstrates that he does think quantum fields (which most consider physical) exist.

He is just a panpsychist (or, more specifically, a "cosmopsychist"), and prefers to say the substance of these "physical" things is mind. If you accept panpsychism, then to say "everything is physical" or "everything is mind" is just a question of perspective. Everything is "something," something which has experiences, and which we could call physics or we could call mind. He calls it mind.

  • Kastrup is an idealist, not a panpsychist. He denies that matter exists as a distinct substance. Only mind exists as a distinct substance. Matter is just an idea in the mind. This does not invalidate that science is true; but it does dramatically change certain things such as the nature of causality. I believe Kastrup would say that physical properties such as mass or electrical charge have no causal powers, all of the causal power is in the universal mind that generates the physical world. Mar 7, 2022 at 12:05
  • @DavidGudeman No, he calls himself a "cosmopsychist," meaning he believes everything is part of a universal mind. He states that the quantum wave function exists (as a mental substance). This fits the definition of a panpsychist; "the world is real and everything in it is mind." He also calls himself an idealist but as he uses the word this is just a second way to describe him.
    – causative
    Mar 7, 2022 at 15:54
  • @DavidGudeman Anyway, you can't reconcile your claims about him with his quote that quantum fields are real. He wouldn't say that mass or electrical charge exist as separate fundamental objects in their own right - he makes the point clearly that they exist only as excitations in the quantum field. But he's not saying everything physical is a dream; he's saying what is called physical is real, but mental.
    – causative
    Mar 7, 2022 at 15:57
  • Well, I'll let it go at that since I haven't read any of his books; I've only read his blog and watched some of his videos. However, I did see a video where he had a discussion with a panpsychist and he drew a distinction between the two views. Mar 8, 2022 at 17:39
  • @DavidGudeman I think what you're thinking of is that he says he's not a constitutive panpsychist, which he defines as a panpsychist that assigns consciousness to individual particles. He is a panpsychist, just not a constitutive one.
    – causative
    Mar 8, 2022 at 17:43

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .