There have been a number of attempts recently to externalise consciousness, or at least extend it beyond the skull. In Out of Our Heads, Alva Noë launches a very broad-based attack on the idea that it’s all about the brain, drawing in a wide range of interesting research – mostly relatively well-known stuff, but expounded in a style that is clear and very readable. Unfortunately I don’t find the arguments at all convincing; I’m not unsympathetic to extended-mind ideas, but Noë’s clear and thorough treatment tended if anything to remind me of reasons why the assumption that consciousness happens in the brain looks so attractive.
I’m happy to go along with Noë on some points: in his first chapter he launches a bit of a side-swipe at scanning technology, fMRI and PET, pugnaciously asking whether it is ‘the new phrenology?’ and deriding its limitations: this seems a useful corrective to me. But in chapter two we are brought up short by the assertion that bacteria are agents. They have interests, and pursue them, says Noë; they’re not just bags of chemicals responding to the presence of sugar. Within their limits we ought to accord them some sort of agency.
To me, proper agency requires an awareness of what acts one is performing and the idea that bacteria could have it at any level seems absurd. How did we get here? Noë’s case seems to be that the problem of other minds is effectively insoluble on rational empirical grounds; we can never have really solid reasons for believing anyone else, or any other entity, is conscious; yet we find ourselves unable to entertain seriously the idea that our fellow-humans might be zombies. This, he thinks, is because we have a kind of built-in engagement, almost a kind of moral commitment. He wants to extend this to life fairly widely, and of course if brainless bacteria can have agency, it tends to show that the brain is a bit over-rated. I think he’s unnecessarily pessimistic about the evidence for other conscious minds; as a matter of fact books like his are pretty spectacular evidence; how and why would human beings produce such volumes, examining the inner workings of consciousness in minute detail, if they didn’t have it? But bacteria have yet to produce such evidence in their own favour.
Noë rests a fair amount of weight on experiments which show the remarkable plasticity of the brain: notably he quotes experiments on ferrets by Mriganka Sur. New-born ferrets had their brains rewired in such a way that the eyes fed into auditory, rather than visual cortex; yet they grew up able to use their eyes perfectly well. This shows, Noë suggests, that no particular part of the brain is required for vision. That might be so, but that in itself does not show that no brain at all will do the job, and obviously it won’t: if the ferrets’ optical nerves had been linked with their teeth, or left dangling unattached, they would surely have been unambiguously blind. The belief that consciousness is sustained by the brain does not commit us to the view that only one specific set of neurons can do the job. Noë explains, quoting an experiment with a rubber hand, how our sense of our selves and where we are can be moved around in a remarkably vivid way. For him, this shows that where the brain is doesn’t matter; but for others it seems equally likely to suggest that what the brain thinks is crucial and where our real hand is doesn’t matter at all.
Noë wants to claim that the frequently quoted thought-experiment of a brain in a vat, extracted from the body but still living and thinking, is impossible in principle (we know it’s impossible in practice, at least currently). He suggests that even if we did manage to sustain a brain artificially, the supporting vat, providing it with oxygenated blood and all the other complex kinds of support it would need, would actually amount to a new body. This nifty bit of redefinition is meant to show that the idea of a brain without a body will not fly. But the real point here is surely missed. OK, let’s accept that the vat is a new body: that still means we can swap bodies while maintaining an individual consciousness. But if we keep the body and swap brains… it just seems impossible to believe that the consciousness wouldn’t go with the brain.
This perception seems to me to be the unshiftable bedrock of the discussion. Noë expounds effectively the case for regarding tools and even parts of the environment as parts of our mental apparatus; and he brings in Putnam’s argument that ‘meaning isn’t in the head’. But these arguments only serve to expand our conception of the brain-based mind, not undermine it.
My sympathy for Noë’s case returned to some degree when he discussed language. He notes that for Chomsky and others language seemed a miraculous accomplishment because they misconstrued it as an exercise in the formal decoding of a vast array of symbols. In fact, language is an activity rather than a purely intellectual exercise, and develops in a context, pragmatically. I’d go along with that to a great extent, but while Noë sees it as proving that our decoding brain isn’t the crux of the matter after all, it seems to me it proves that decoding isn’t really what our brains are doing when they process (a word Noë would object to) language.
I sympathised even more with Noë when he attacked the idea that reality is, essentially, an illusion. If this were the case, the brain would be the all-powerful arbiter of reality (although it might seem that if the world is an illusion, the brain must be one too, and we should be dealing with a mind whose actual nature need not be pinkish biological glop). But he seemed to be back on weak ground when he concluded by taking on dreams. Dreams, after all, seem like the perfect evidence that the brain can produce conscious experience without calling on the senses or the body. Noë argues that dreams are more limited than we think, that not all waking experiences can be reproduced in dreams, which are always shifting and inconstant. This might be true, but so what? If the brain can produce conscious experiences on its own – any conscious experiences – that seems to show that, with all caveats duly entered, the brain is still where it really happens.
It’s a well-written book, and for someone new to consciousness it would provide many excellent short sketches of thought-provoking experiments and arguments. But I’m staying in my head.