The Kekulé Problem

Cormac McCarthy asks an interesting question here, and gives the wrong answer, also interestingly. Along the way he manages to describe in simple language a fundamental problem of how our minds work, one that he rightly says, remains mysterious – though I think I have a clue.

McCarthy briefly retells the story of Kekulé, who struggled to understand the form of the benzene molecule. A dream of a lizard biting its own tale (like Ouroboros) prompted him to realise that the molecule was a ring. So we may conclude that Kekulé’s unconscious had done the work for him and found the solution. McCarthy rightly contends that most of our problem-solving, our maths and so on, is done unconsciously. We can reason about things consciously using language and other symbols explicitly, but it is a very slow, clunky and ineffective business. In fact the main point of doing this explicit reasoning (writing out propositional calculus or hand-simulating the running of a computer program for example) is usually to drag into conscious, recordable form the logic or processes we would normally use unconsciously.

The problem posed by McCarthy is: why didn’t Kekulé’s unconscious just tell him the answer, instead of sending it as an esoteric symbol in a dream? The unconscious understands language, he says, or it wouldn’t have understood the problem Kekulé was trying to answer in the first place (I don’t think that is clearly true). He concludes that the unconscious has been running our mental lives quite successfully for millions of years before language came along: it therefore distrusts and dislikes language and prefers other ways.

That isn’t right. Part of the problem here is too strong a separation between conscious and unconscious, which are really just the silent and the talky bits of the same process. Kekulé’s unconscious could not speak to him in words because any mental content that is in the form of language is automatically part of consciousness. Or to put it another way, his unconscious did tell him the answer in words, the words (let’s say) ‘By golly, benzene is a ring!’ But those words appeared as thoughts of Kekulé’s own, necessarily conscious thoughts. They were certainly put together by unconscious processes: as McCarthy recognises, all of our conscious verbal thoughts and utterances are constructed by unconscious processes – or we should get involved in an infinite regress.

How does the unconscious pull all this off? I have claimed before that our conscious thoughts and much of our higher cognition is grounded in recognition. The recognition of larger entities from smaller ones (and back down elsewhere) allows us to leap from present stimuli to distant, future or hypothetical ones, and finally into the realm of abstraction where we can recognise even the pure forms of mathematics. When we think about a problem, we do not typically do computations or talk to ourselves (though we might do that too). We hold the problem in mind and wait for our faculties of recognition to identify something that makes sense. I’m sure that’s what happened in Kekulé’s mind.

The same processes ultimately ground our use of language. As I have suggested, the grunt emitted when digging the dry riverbed can be recognised as part of the digging process, another part of which may be the desirable item of water. The grunt can therefore become an invitation to dig: and I think invitations and commands probably came before names.

Anyway, though I have a somewhat different answer, I think McCarthy is, as it were, digging in the right place with the right tools..

6 thoughts on “The Kekulé Problem

  1. Good to hear from you Peter!

    Recognition is an interesting way to put it. I often feel like what’s happening is pattern completion. And people like Anil Seth talk about prediction, Which may be different ways of describing the same idea, although the different descriptions may be capturing important nuances.

  2. Some of my favorite thinkers and practitioners appear on your masthead for this blog/post. A lot of things are being labelled “critical” these days. My first experience was critical thinking. Theretofore, I did not know there was any other way to seriously think about anyone, anything. Complexity, then, was only beginning to be a problem—postmodernism had not fully emerged. Then Dennett and Hofstadter showed me how to joots. Critical race theory hit the radar more recently. I think it is a scam and have said so elsewhere. Jootsing helped. thanks, Dan. So far as the benzene problem was solved, that is a useful thing. However, I must protest the unconsciousness notion. Even Searle rejected that, years ago. But, maybe I am being too critical. Welcome, all.

  3. I think there’s a certain conflation between ‘knowing something’ and ‘having it presented in language’ going on. One can’t equal the other: we must understand the language first before we can know what’s being told; conversely, in the production of language, we know what we want to say before putting it into words (which is why we sometimes struggle to do so).

    So it’s interesting that McCarthy seems to believe that the unconscious presenting something to the conscious mind (for a moment accepting the separation there) in terms of language would be the most direct way of letting it know that something. Why include the middle man of language at all? Presumably, there’s all sorts of information transfer between conscious and nonconscious processes going on in the brain, leading to things like that gnawing feeling in my gut when I’ve forgotten to prepare for a meeting today while I don’t yet consciously know that I have. Parts of the brain telling each other things in terms of language seems a bit like talking to yourself via mail.

    Of course, the question then becomes: why do we do it at all? Most of my conscious thought is in terms of language, it seems—some inner narrative chattering merrily on. Is this my brain telling me—that is, itself—about my thoughts? Again, that would be a strange way to go about it: my brain already knows my thoughts (and you can make the experiment of cutting off the stream of narrative before a thought is completely expressed—it seems to me that I still sorta know what was going to be ‘said’).

    There’s probably some sort of Dennettian story about things like warning calls to the group being internalized in some autostimulating fashion that leads to the inner narrative eventually, but I’ve come to distrust such stories. I think Mercier and Sperber get a lot of this right in ‘The Enigma of Reason’: our conscious, explicit, System 2 thought process isn’t really the ‘rational engine’ we generally take it to be, just saddled with inexplicable flaws like confirmation bias and other fallacies, but a perfectly well-functioning system aimed at making our actions socially justifiable that is only accidentally shackled to producing sound reasoning. From this point of view, such an inner narrative is essentially just a dress rehearsal: does this sound convincing? Will this be defensible to my peer group?

    But this leaves the enigma of why Kekulé’s subconscious bothered to package the knowledge it had arrived at into some symbolic form, at all. Why didn’t he simply wake up knowing the answer? I think it’s instructive to think of the unconscious, System 1-style processing as working somewhat like a neural network. In such systems, it’s not unusual to see something like ‘confabulating’: whatever a particular network has been trained on, it will interpret into the world. A dog-recognizing system will see dogs everywhere, in particular with noisy input data. Dreams may be something like making something from nothing—the input data being essentially random noise. Remember Google’s DeepDream? You start out with noise, you get dog pictures. So, some part of Kekulé’s subconscious machinery may have zeroed in on ring-like structures, which had the effect of them turning up in his dreams—clad in the mythological image of Ouroboros.

  4. I spent an hour or two today composing a different response to this, attempting to counter McCarthy’s assumption that Kekulé’s subconscious must have understood language, then I went to check a few details… and learned a relatively cheap lesson in not building too much on anecdotal evidence.

    It seems that Kekulé told several inconsistent versions of the story. In one (maybe the first), he was not sound asleep, but experiencing a reverie or daydream (perhaps a hypnagogic state?) [1] It also seems that the core of the benzene molecule had already been represented as a circle (though whether this was intended to be taken literally seems to be in doubt),[2] and Kekulé may well have been aware of this. In this light, it does not seem clear whether the metaphorical mental image preceded the chemical insight.

    Even if the now-common version of the story is correct, we are not rationally required to assume Kekulé’s subconscious solved the problem. For example, the dream may have been coincidental – this would not rule out the fresh memory of it prompting him to see a solution to the benzene problem in a ring of carbon atoms.

    [1] https://psy-minds.com/kekules-dream-structure-benzene/

    [2] https://en.wikipedia.org/wiki/Johann_Josef_Loschmidt

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