Call.  It isn’t actually your brain that does the thinking at all. In fact, the very idea that it does is virtually incoherent: not just wrong, but meaningless: the mereological fallacy. Only you as a whole entity can do anything like thinking or believing.

That’s pretty much the bombshell dropped by Max Bennett and Peter Hacker in their 2003 blockbuster Philosophical Foundations of Neuroscience. Mereology is a branch of logic dealing with the relations of parts and wholes; it represents one of the attempts which were made to sort out the chaos left behind in the wake of the catastrophic collapse of Frege’s theories. Bennett and Hacker’s book has given the term a new lease of life with a somewhat looser sense. Actually, the book is large and complex, and I can’t do anything like justice to it here, but the idea of the mereological fallacy, a kind of leitmotiv running through the book, certainly deserves some attention.

What do they mean? If I don’t think with my brain, do I think with my foot? There is, of course, a sense in which my foot seems to know things. It ‘knows’ roughly what forces to apply where in order to keep me walking straight. My arm knows how to move in order to be in the right place to catch a ball heading in my direction, not a process I myself could describe in any great detail. But although athletes talk about muscle memory, this kind of knowledge is really little more than a metaphor, or at best an example of knowing how to x, not of knowing that x. It certainly isn’t what Bennett and Hacker have in mind, anyway: the last thing they want to do is transfer cognitive functions to another mere part of the body: their point is that only whole people have these capacities.

But what’s a whole person? If my foot, or even my leg, is cut off, it doesn’t seem to have any relevance to most of my thought processes. Indeed, if the stock science fiction/philosophy example is to be believed, a brain removed from the body altogether and sustained in some kind of life-support tank could perfectly well go on thinking for itself. That may be no more than a thought-experiment with a dubious basis in medical reality, but it does suggest that the brain is the thinking organ, just as the heart is the blood-pumping organ.

I think that to appreciate Bennett and Hacker’s point properly, you have to consider it in historical context (they provide plenty of this: I’m afraid poor Descartes gets yet another drubbing for inflicting his dualism on us all, though for once his positive contribution is also acknowledged). Philosophically, I think we can see the doctrine of the mereological fallacy as being in opposition to the problematic old theory of sense-data. For a very long time, it was accepted that we didn’t see the world, we saw sense-data (or images, or some similar intermediary). In philosophy, this view was popular because it seemed to make it easier to explain cases of error or illusion; it was just defective sense-data. Scientifically the fact that a nice image appeared on the retina, within the eye, must also have predisposed people in its favour. If discussions of the senses had been mainly about touch, where there is no apparent intermediary, rather than sight, things might have been different.

On the whole, I think it has been accepted within philosophy that the sense-data point of view was a confusing mistake: when we see a table, we see a table, not some patches of brown within the visual field: the brown patches, the images and the sense-data, if there are such things, are just part of the means by which we see. Bennett and Hacker, if I understand them correctly, want a root and branch application of this kind of revised thinking to all aspects of cognition. Brains sustain patterns of neuron firing, and patterns of neuron firing correlate with cognitive activity: but to say that the firing neurons are the thoughts is just a mistake. As a bonus, this (apparently) eliminates the binding problem: if your experiences aren’t in your brain at all, the question of where in your brain the different elements are put together no longer arises. (But perhaps some related questions still do!)

Up to a point, this is quite right, and a necessary corrective. I think Bennett and Hacker are probably right to think that Crick, for example, has fallen into the trap they are describing: but it’s not so clear to me that everyone has. Some people, and Crick was one of them, do assert that neurons firing just are mental experiences, full stop: but most people, even those who assert the identity of mental and neural events, only mean that the two things are different aspects of the same phenomenon; the same, but on different levels of interpretation.
Perhaps an analogy will help to make this clearer. Hennett and Backer, let’s say, have a controversial theory about phone conversations: when you call your mother, they say, the conversation does not go through the local telephone exchange: it can’t be found in some cable somewhere: that’s just nonsensical – it takes place between you and your mother. Now the theory may seem a little unexpected, but the thing is, the opposite view has held sway for a long time. People are always saying things like “You imagine you’re talking to your mother, but actually science has conclusively established that you’re actually talking to the phone. OK, the phone may tell you something about what your mother is saying – maybe quite a lot – but it’s only the phone you’re talking to. You actually have no contact with your mother, and no certainty about what she’s telling you.”

In this case it’s obvious that there are two equally valid levels of interpretation: it’s just that the two sides are being pig-headed about recognising it. Of course you’re talking to your mother, and having a conversation which we wouldn’t normally describe as happening in a cable: but in another sense you are addressing the phone (your mother’s miles away!) and there is a sense in which the conversation passes though the local exchange. If we imagine the telephone exchange as very old-fashioned (and I do) it’s actually crucial that the operator knows which plug and socket your words need to travel down.

So yes, it is people who see things and think thoughts: but so long as we keep hold of that fact, and don’t allow ourselves to be seduced by the sterile charms of eliminative reductionism, surely we can safely talk in another valid sense, about the brain doing these things?

(Some subsequent discussion is here.)


  1. 1. W. R. (Bill) Klemm says:

    I believe it is only a minority who believe it is fallacious to think the brain thinks. The minority’s point is that brain’s can only think if they function as only one part of a whole body. While this view is fashionable among some philosophers, many neuroscientists consider the position overstated, especially when extended to the say that the firing of neurons cannot constitute “thought.” If thoughts don’t come from neural activity, where do they come from? A neuroscientist only wants an operational definition of “thought” and can find it in a petri dish where a brain slice thinks in the sense that it can process information, from electrical stimulation of an input pathway.

  2. 2. Alex Powell says:

    Superb book and the fallacy is solid. (A) firing neurone/s cannot constitute thought because (a) firing neurone/s is/are (a) thing/s that is/are doing something else and (a) thing/s doing something else is not a thing. It’s (a) thing/s doing something else and thought is a (singular) “thing”. Thoughts are immaterial because they come from an immaterial cause – mind. Mind is designated immaterial because no material has ever been shown to constitute “mind”. Yet we are convinced that there is such a thing that acts as the basis of the word mind. In all of human history, amongst all of the trillions and trillions of dead bodies when someone dies no one has identified a left over mind – so it must be immaterial. The telephone analogy, subject=talking, is not applicable here because it merely rests on the presence or no of the mother. Hence the correct subject of this analogy is “presence” predicated to “talking”. Is the mother present because they are talking? “Mom I’m getting that pain in my chest again!””I want you to put the phone down right now and dial 999!” There is no interpretation here. But what if I am talking to a call centre in India? Would I tell them I’m having pains in my chest. Even if I told them would I be more concerned about transferring that money? To say it doesn’t matter what is adressed in neuroscience is the same as saying it doesn’t matter who we talk to and when. As long as we talk to someone everything is going to be okay. Brave, very brave, but not true in the world and so defintely not true for neuroscience.

  3. 3. All This Neuroscience BS has Got to Stop « Chasing Fat Tails says:

    […] First, this ignores the criticisms I made previously: whatever the mind is, it won’t be found in individual neuron connections.  Second, this kind of talk ignores a more fundamental problem that neuroscientist researchers (and the article) commit all over the place: the mereological fallacy. […]

  4. 4. Yogi Mat says:

    I would urge commenters to read SOUL DUST by Nicholas Humphreys. Nearly finished the first read and although it is not entirely free from trendy, neuroscience babble the contextual references he relies on are broad enough to offer something very substantial in this field of study. Serious consideration is given in his hypothesis that “consciousness as an illusion” is actually underpinned by natural selection. The “hard problem” is dealt with here head on.

  5. 5. Claudia says:

    Don t understand how exactly i got in here but i m really glad i ve found it. Neaah… i m starting to believe google is begining to read my mind 🙂 Nice work!

  6. 6. BTP says:


    […]Conscious Entities » Blog Archive » The mereological fallacy[…]…

  7. 7. Brains, Boats & Baseball bats — some thoughts on fMRI – Neurologism says:

    […] phenomena, even when inspired by an accurate scientific picture, often fall prey to the “mereological fallacy“, i.e.,  the conflating of parts of a phenomenon for the whole. Bits of muscle don’t […]

  8. 8. The Knight (who says "Ni") says:

    There is nothing logical (or for that matter merry) about the mereological fallacy. Thinking (in the general sense) occurs in the brain, and brains are made of neurons (and other cells). Therefore (collectively) neurons are responsible for thinking. However the activity of neurons is (in large part) dependent upon sensory information, which comes from the body, and the external environment. Hence changes in the body and environment affect the activity of neurons, hence they affect thoughts and thinking, but they do not DO the thinking. Anyone who thinks otherwise should volunteer for a frontal lobotomy.

  9. 9. Steven Hobbs says:

    Great commentaries all around. Thanks to whoever coined this logical fallacy, “mereological fallacy”. Slippery distinctions of (“mere”) brain gives rise to thought. [Is brain conscious? Or is consciousness a brain excretion?] Neurological events are important to report as are conscious distinctions. What seems often left out is subjectivity of our conversation, and context of the situated participants. In other words, when we speak of neurological events we are speaking in one contextual framework distinct from experiential (consciousness); and when we speak of both we add a third knowledge base with it’s own linage, e.g., philosophy of mind. A reductive investigation is useful if myopic, metaphysical or ontological investigation is without mooring sans evidence of reductive neurological research, and both provide another synthetic insight.

  10. 10. Tony says:

    I am surprised no one has mentioned “The Biology of Cognition” otherwise known as Autopoiesis Theory that deals comprehensively with precisely this issue way back in 1972 (in Spanish)
    Maturana and Varela claim with good evidence that the domain of ones components (anatomy physiology neurobiology) is incommensurable with the domain of behaviour. (language, being, behaviour as a unity)
    See “Autopoiesis and Cognition The Realization of the Living” H Maturana and F Varela” D. Reidel 1980
    See also Randall Whitaker “The Observer Web”
    Maybe I am missing something??

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