What a brilliant puzzle can teach us about consciousness.

Narcis Marincat
Is Consciousness
Published in
5 min readMar 8, 2020

I enjoy figuring out logic puzzles that come my way, and one of my favorite puzzles of all time is this one:

Nob Yoshigahara’s puzzle, taken from Alex Bellos [1].

It was made by Nob Yoshigahara, who is a famous puzzle maker, and who has been heard saying that he considers this his masterpiece [1]. What you have to do is figure out what number you should replace the question mark with. Seems simple enough, right? Until you realize that the number 7 in the final circle is not a typo, which I assure you it isn’t. And that’s because initially, the first ‘solution’ that pretty much everyone considers is tackling the numbers in groups of three, and subtracting the number on the upper left from the number on the upper right to get the number on the lower center, like this:

99–72=27; 45–27=18; etc.

That is, until you get to the last three numbers, and you find that 21–13 is not equal to 7. Now, I won’t give you the correct solution, that’s one that you’ll have to find for yourself. However, for our purposes, the correct solution doesn’t matter (which is why I can let you rack your brain on what it actually is) — what matters is that when you reach the last three numbers, you realize that the model you had in mind is not the solution to the problem. Even though it was compatible with all the other numbers until the last one, the fact that it was not compatible with even a single number means that there’s another solution out there, which you will recognize by the fact that it fits the entire puzzle.

Now, let’s turn to one of the most famous concepts in the philosophy of consciousness, known as the hard problem of consciousness. Initially formulated by David Chalmers, the hard problem of consciousness is, in his words, “how the physical stuff of the brain gives rise to subjective experiences.”

The hard problem of consciousness is how the physical stuff of the brain gives rise to subjective experiences.

Your subjective experience includes taking in a rose’s redness, the smell of a freshly baked cookie, the texture of your lover’s skin. Prof. Chalmers explained it well in a recent podcast on Sean Carroll’s Mindscape[2]:

We can walk we can talk, we can do all of the things we can do, we can communicate with each other, we can solve scientific problems but a lot of that is at the level of sophisticated behavioral capacities — things that we can do. And when it comes to explaining behavior, we’ve got a pretty good lead on how to explain it. In principle at least you find that circuit in the brain, a complex neural system which maybe performs computations, produces some outputs, generates the behavior, then in principle you’ve got an explanation. It may take a century or two to work out the details but basically you’ve got the standard model in cognitive science…This is what 20 odd years ago I’ve called the ‘easy problems’ of the mind and of consciousness in particular, these behavioral problems. Nobody thinks they’re easy in any ordinary sense. The sense in which they’re easy is that we have a paradigm for explaining them. […] However, the really distinctive problem is posed not by the behavioral part, but by the subjective experience. By how it feels from the inside to be a conscious being. I am seeing you right now, I have a visual image of colors and shapes that are sort of present to me in the inner movie of the mind. I’m hearing my voice, I’m feeling my body, I’ve got a stream of thoughts running through my head, and this is what philosophers call consciousness, or subjective experience. And I take to be one of the most fundamental facts about ourselves. […] Then the question is: How do you explain it? And the reason why we call it the hard problem is because the standard method of just explaining behaviors and explaining the things we do doesn’t quite come to grips with the question of why we have a subjective experience.“

Looking at it, it seems as the hard problem of consciousness is not unlike the problem of the 7 in Yoshigahara’s puzzle. If we didn’t know any better, trying to figure out how we could get 7 by subtracting 13 from 21 could have been called ‘the hard problem’ of the puzzle. But we know in fact that this ‘hard problem’ of the puzzle is a symptom of the fact that the model we see working on the rest of the puzzle is not the right one, even though it was compatible with all of the other parts of the puzzle, or what we can call ‘the easy problems’ of the puzzle.

The idea that you have “a circuit in the brain, a complex neural system which maybe performs computations, produces some outputs and generates the behavior” is itself a model, a paradigm for explaining the processes that give rise to consciousness. But even though it may be compatible with some aspects of conscious experience, the fact that it is not compatible to ALL of the aspects may just be a symptom of the fact that it is not the right model. After all, subjective experience is not a typo. Your subjective feelings and perceptions exist, and any model of consciousness that cannot explain it just as well as, say, the aspects of consciousness related to behavior, may just not be the solution to the consciousness puzzle.

Subjective experience is not a typo.

And just like the solution to Yoshigahara’s puzzle requires a radical divergence from the initial model we tested out (hope you figure it out), the solution to the consciousness puzzle may be quite different from the mechanistic approach of “brain circuits doing computations”. In ‘Is Consciousness..’, we’ll look to see if any current theories of consciousness rise to the challenge. Until then however, what Yoshigahara’s puzzle teaches us is this:

The hard problem of consciousness may be pointing out that the model we’re using to solve the ‘easy problems’ is not the right solution, although it may seem compatible with certain aspects of the conscious experience.

[1] Bellos, A. (2017). Can You Solve My Problems?: Ingenious, Perplexing, and Totally Satisfying Math and Logic Puzzles. The Experiment.

[2] Carroll, S. (2020). David Chalmers on Consciousness, the Hard Problem, and Living in a Simulation [Podcast]. Retrieved 7 March 2020, from Apple Podcasts.

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Narcis Marincat
Is Consciousness

Psychology, Neuroscience & CompSci graduate (UCL & Royal Holloway). Interested in consciousness, AI, philosophy, sociology & cyberpsychology, or mind+tech.