Are (or were) there any philosophers that argue (or argued) that the human brain cannot be understood using a human brain, i.e. that it's impossible for a human to understand the human brain completely?

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    Why would you think philosophers have essential insight into what is fundamentally an empirical question in neuroscience? Philosophers should care about the answer, of course, but it's going to depend on the experimental details.
    – Rex Kerr
    Oct 5, 2014 at 17:47
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    @rex kerr if this is an empirical question, how would you rephrase it in neuroscientific terms? I am particularly interested in how you would translate "understand" in terms of, say, neuron signalling. Oct 5, 2014 at 21:37
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    @quen_tin - Neuroscience: "Does the human brain operate using a compact set of principles?" (Necessary to fit it in the human brain--a computational system cannot completely represent itself.) If the first project's answer is yes, more neuroscience: "What are those principles?" Once found, some educational psychology: "Can we gain an adequate understanding of the compact set of principles, with adequate training?"
    – Rex Kerr
    Oct 5, 2014 at 23:14
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    Well ... human brains understand human knees. So the question comes down to asking what is the difference between a brain and a knee. Both are physical objects composes of the building blocks of matter. Both are biological structures. Why shouldn't we be able to understand brains? It's minds we don't understand. Brains are easy.
    – user4894
    Oct 7, 2014 at 1:37
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    Brains are easy... compared to minds.
    – JosEduSol
    Oct 7, 2014 at 17:01

9 Answers 9


From way out in left field we can look at Computation Theory as a model of the brain. The first and most basic result in Computation Theory is Turing's result on the halting problem.

Basically, if the brain is a computing machine of any variety without specialized access to truth other than data, (Turing's Thesis), then there are real questions about its own behavior it cannot address.

Specifically, it cannot propose a limited set of rules that will determine what questions it can and cannot answer definitively, in general.

  • Finally something related to the question.
    – user132181
    Oct 7, 2014 at 15:26
  • I think this question is moot enough you are scaring off the real philosophers. From a materialist perspective, it is closed, as I note. The result is from math, not philosophy. From an idealist perspective, who cares about "brains"?
    – user9166
    Oct 7, 2014 at 15:31
  • Would two (or more) Turing machines, one doing meta analysis on the other, do any better? More precisely: Would any configuration of Turing machines being able to 'read/write' from each other, be able to solve the halting problem.? Or is a completely kind of 'computation' required?
    – christo183
    Dec 10, 2018 at 6:58
  • @christo183 No, combinations of Turing machines are just bigger Turing machines. Even if you add a reasonable degree of indeterminacy, they don't increase the class of computable results. (So free will does not help solve this problem either.)
    – user9166
    Dec 10, 2018 at 15:56
  • I believe this answer is a good answer but did not upvote it because I didn't learn a lot about the subject and can't verify that it's not saying something wrong without me knowing it. I might upvote it if you explain it in detail with references that I can understand.
    – Timothy
    Dec 12, 2018 at 5:16

The wording makes it a bit difficult to respond. In the first place, no brain, rock, quark, or eggplant can be isolated in a specimen jar and "understood completely." In the second place, you specify the material "brain" while the unavoidable issue of "mind" lurks in the term "understand."

While a "mind" understanding itself may seem like a paradox of self-reference or a "halting" problem, there are ways around that. Churchland's eliminative materialism, for example, proposes that, yes, everything about mind can be reduced to neural states that can be mathematized, modeled, and replicated, but will require a different sort of nonlinguistic reference system. Many argue the reverse.

It may be that "mind" can understand "brain" if we treat mind as immanent and continuous and "brains" as discontinuous. Thus "mind" cannot observe or understand itself, from the outside, so to speak. Nor, for that matter, can one brain physically inspect itself. But our collective "mind" can certainly inspect a series of "brains" and accumulate a scientific understanding of their operations. I see no reason why such brain science would have any unique limits, aside from the obvious ethical limits.

If you mean "understand" according to Hobbes' definition of being able to reproduce something...well, people reproduce brains all the time. Cognitive scientists just want to see if they can reproduce them without sex. That's their problem.


I think it's completely impossible for one to fully know everything all the neuron cells in their own brain are doing. If you've undergone sudden savant syndrome as described in this question, you might be able to quickly learn all the controls of an airplane and have a hyperawareness of every single one of them and derive other properties of the set of all controls and their functions, but your own brain has about 10^11 cells each of which can make thousands of connections and the very act of having that trait necessarily means those cells are interacting in such a complex way that you cannot know what every single one of them is doing with such a hopelessly large number of them. Anything you can fully understand, you can make computations on. Giving a neural description of how the brain works, it cannot take in all the bits it can in theory store in the form of connections and keep a record of all those computations on those bits by storing even more bits in the form of connections. I'm not sure if when you were 6, you had a simple enough brain that if you later underwent sudden savant syndrome, you could now fully understand how your brain worked then but if so, that trait made you now have a brain that's so complex that you cannot fully understand it even with that trait.

Some people might be hoping the brain is simple so that they can fully understand it. I do not want a brain that's so simple that it can be fully understood because then I will not have any hyperawareness and will be capable of understanding so little and don't want one in the future but I might have had one when I was 6 and am fine with that because it's the past and at the time, I probably wasn't suffering from having that type of brain and from my theories, I feel optimistic that according to one definition, my brain is irreversibly getting closer to sudden savant syndrome and the process can be slowed down but cannot be reversed although I can lose abilities while I'm part way there appearing to be going the other way then gain megasavant skills after I finish getting there if I live long enough to.


Colin McGinn addresses this problem via an examination of the mind/ body issue.

The specific problem I want to discuss concerns consciousness, the hard nut of the mind-body problem. How is it possible for conscious states to depend upon brain states? How can technicolour phenomenology arise from soggy grey matter? What makes the bodily organ we call the brain so radically different from other bodily organs, say the kidneys the body parts without a trace of consciousness? How could the aggregation of millions of individually insentient neurons generate subjective awareness? We know that brains are the defacto causal basis of consciousness, but we have, it seems, no understanding whatever of how this can be so. It strikes us as miraculous, eerie, even faintly comic. Somehow, we feel, the water of the physical brain is turned into the wine of consciousness, but we draw a total blank on the nature of this conversion. Neural transmissions just seem like the wrong kind of materials with which to bring consciousness into the world, but it appears that in some way they perform this mysterious feat. The mind-body problem is the problem of understanding how the miracle is wrought, thus removing the sense of deep mystery. We want to take the magic out of the link between consciousness and the brain. 1 Purported solutions to the problem have tended to assume one of two forms. One form, which we may call constructive, attempts to specify some natural property of the brain (or body) which explains how consciousness can be elicited from it. Thus functionalism, for example, suggests a property namely, causal role which is held to be satisfied by both brain states and mental states; this property is supposed to explain how conscious states can come from brain states.2 The other form, which has been historically dominant, frankly admits that nothing merely natural could do the job, and suggests instead that we invoke supernatural entities or divine, interventions. Thus we have Cartesian dualism and Leibnizian pre-established harmony. These 'solutions' at least recognize that some- thing pretty remarkable is needed if the mind-body relation is to be made sense of; they are as extreme as the problem. The approach I favour is naturalistic but not constructive: I do not believe we can ever specify what it is about the brain that is responsible for consciousness, but I am sure that whatever it is it is not inherently miraculous. The problem arises, I want to suggest, because we are cut off by our very cognitive constitution from achieving a conception of that natural property of the brain (or of consciousness) that accounts for the psychophysical link. This is a kind of causal nexus that we are precluded from ever understanding, given the way we have to form our concepts and develop our theories. No wonder we find the problem so difficult! (Colin McGinn, 'Can We Solve the Mind--Body Problem?', Mind, New Series, Vol. 98, No. 391 (Jul., 1989), pp. 349-366: 349-50.)

As befits a philosopher, McGinn does not leave things at this point but goes on to argue his case. You would need to read his article (not amenable to summary here) to decide how, and how cogently (or otherwise), he argues his point. But McGinn, a notable UK philosopher, is an example of a philosopher who argues for the standpoint outlined in your question.


I don't know whether there were any philosophers who said so. So I am leaving out the first part of your question.

But, for the main question: It is impossible for a human brain to understand the human brain completely.

This is because, after a certain limit the learner discovers a confusing parameter--'the consciousness' of the study material (the brain). And it begins to disturb the learner's 'brain' also. And when the consciousness interferes in the study on the brain, it becomes more complected because, consciousness is never perceived by senses or any other equipment (like other things). (Don't forget that the study is 'assigned' to the brain.) Also, when we try to analyze the brain of a person who has great spiritual powers, we will be stranded because by connecting his brain we can never give explanations to his 'activities'.

So, a complete understanding of the brain is impossible.


Are (or were) there any philosophers that argue (or argued) that the human brain cannot be understood using a human brain, i.e. that it's impossible for a human to understand the human brain completely?

Kurt Gödel addressed this consideration in their incompleteness theorems within "On Formally Undecidable Propositions of "Principia Mathematica" and Related Systems" (1931), specifically

In that article, he proved for any computable axiomatic system that is powerful enough to describe the arithmetic of the natural numbers (e.g., the Peano axioms or Zermelo–Fraenkel set theory with the axiom of choice), that:

  1. If a (logical or axiomatic formal) system is consistent, it cannot be complete.
  2. The consistency of axioms cannot be proved within their own system. (emphasis added)


In hindsight, the basic idea at the heart of the incompleteness theorem is rather simple. Gödel essentially constructed a formula that claims that it is unprovable in a given formal system. If it were provable, it would be false. Thus there will always be at least one true but unprovable statement. That is, for any computably enumerable set of axioms for arithmetic (that is, a set that can in principle be printed out by an idealized computer with unlimited resources), there is a formula that is true of arithmetic, but which is not provable in that system.



It seems obvious that the brain cannot understand anything. The question is therefore easy.

To make the answer longer I'll ask - why anyone would think the brain can understand anything? On what grounds? We might as well suppose an abacus can understand mathematics.


The brain is inferred from sensations (mostly visual). Where do our sensations take place? The brain. But the brain is inferred from our sensations...core dump.

  • I know. This answer is worth less than 2 cents, but the question is a good one. It stimulates many other questions, e.g. what do we mean by "understand?" Oct 7, 2014 at 9:40

Using only the brain? As in logically deducing it? No, I think not. How could we ever hope to know anything about it in reality without science? If we first used science to reveal all of it's mechanics and processes, then, perhaps we could then explain it in such a way that could be understood by the mind only. we are still a long way from fully comprehending all of it's many secrets.

To backpedal for a moment, I could see having some understanding of it on a basic level (eg "I'm hungry. but how to "I" know that? if my brain is not in my stomach, it must have a method to receive a message that I require food." But I think that only covers some aspect of your senses. Using similar methods, you could deduce further, but I cant see how you could understand other, less physical aspects such as thoughts, memories and feelings outside of being driven by evolutionary forces.

I think it's speaks well for us to not understand it 100%. At least if what David Eagleman says is true: “If our brains were simple enough to be understood, we wouldn’t be smart enough to understand them.”

  • First off, welcome to philosophy.SE. I'm not seeing much philosophy or argument in this answer. There may be some grammar issues that are making it harder for me to follow.
    – virmaior
    Sep 13, 2015 at 5:27

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