Tag Archives: Alva Noë

Thinking Backwards

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backwardIn the course of this review of Carlo Rovelli’s Seven Brief Lessons on Physics, Alva Noë asks a fascinating question: does it make any sense to imagine that one might think backward?

In physics we are accustomed to thinking that entropy always increases; things run down, spread out, differences are evened out and available energy always decreases. Are cognitive processes like that, always going in one underlying direction? Are they like a river which flows to the sea, or are they more like a path we can take in either direction?

Well, we can’t talk backwards without careful preparation, and some kinds of conscious thought resemble talking to oneself. In fact, we can’t perform most tasks backwards without rehearsal. Unless one takes the trouble to learn zedabetical order, we cannot easily recite our letters in reverse. So it doesn’t seem we can do that kind of backward thinking, at least. We can, of course, read a written sentence in the reverse word order and I suppose that in that sense we can think the same sentence backwards, or ‘backwards sentence same the think’; but we might well doubt whether that truly reverses the thought.

On the other hand, on another level, there seems to be no inherent direction to a chain of thought. If I think of an egg, it makes me think of breakfast, and breakfast makes me think of getting up; but thinking about getting up might equally have prompted thoughts of breakfast, which in turn might have brought an egg to mind. The association of ideas goes both ways. Logical thought needs a little more care. ‘If p then q’ does not allow us to conclude that if q then p – but we can say that not-q gives us not-p. With due attention to the details there doesn’t seem to be a built-in direction to deduction.

The universal presence of memory in all our thoughts seems a deal-breaker on reversibility, though. We cannot forget things at will; memories constantly accumulate; and we cannot deliberately unthink a thought in such a way as to erase it from recollection. This one-way effect seems to be equally true of certain kinds of thought on another level. We have, let’s say, a problem in mind; all the clues we need are known. At some point they come together to point to the right conclusion – Aha! Unless we find a flaw in our reasoning, the meshing of the clues cannot be unpicked. We can’t ununderstand; the process of comprehension seems as irrevocable as the breaking of an eggshell or the cooking of a omelette.

There’s an odd thing about it though. The breaking of the egg is an example of the wider principle of entropy; the shell is destroyed, and later the protein is denatured by heat. The solving of the problem, by contrast, is constructive; we’re left with more than we had before and our mental contents are better structured, not worse. Learning and understanding seems like a process of growth. Like the growth of a plant it is of course just a local reversal of entropy, which has to be paid for through the use of a lot of irretrievable energy; still, it’s remarkable (as is the growth of a plant, after all).

Hang on, though. Isn’t it the case that we might have been entertaining a dozen different ideas about the possible solution to our problem?  Once we have the answer those other hypotheses are dropped and indeed may even be truly forgotten. More than that, the right answer may let us simplify our ideas, the way Copernicus let us do away with epicycles and all the rest of the Ptolemaic system nobody has to think about any more. Occam tells us to minimise the number of angels we require for our theory, so isn’t the growth of understanding sometimes a synthesis which actually has the character of a reductive simplification? That isn’t usually a reversal as such, but doesn’t it involve in some sense the unthinking of certain thoughts? David Lodge somewhere has a character feel a pang of pity for all the Marxist professors in the universities of no-longer-communist countries who must presumably unspool years of patient theoretical exegesis in order to start understanding the world again.

Well, yes, but I don’t think that is truly an unthinking or reverse cogitation. Is it perhaps more like a plant managing to grow downwards? So no, as Noë implied in the first place, it doesn’t really make sense to imagine we might think backward.

Do we care about where?

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macaque and rakeDo we care whether the mind is extended? The latest issue of the JCS features papers on various aspects of extended and embodied consciousness.

In some respects I think the position is indicated well in a paper by Michael Wheeler, which tackles the question of whether phenomenal experience is realised, at least in part, outside the brain. One reason I think this attempt is representative is its huge ambition. The general thesis of extension is that it makes sense to regard tools and other bodily extensions – the iPad in my hand now, but also simple notepads, and even sticks – as genuine participating contributors to mental events. This is sort of appealing if we’re talking about things like memory, or calculation, because recording data and doing sums are the kind of thing the iPad does. Even for sensory experience it’s not hard to see how the camera and Skype might reasonably be seen as extended parts of my perceptual apparatus. But phenomenal experience, the actual business of how something feels? Wheeler notes a strong intuition that this, at least, must be internal (here read as ‘neural’), and this surely comes from the feeling that while the activity of a stick or pad looks like the sort of thing that might be relevant to “easy problem” cognition, it’s hard to see what it could contribute to inner experience. Granted, as Wheeler says, we don’t really have any clear idea what the brain is contributing either, so the intuition isn’t necessarily reliable. Nevertheless it seems clear that tackling phenomenal consciousness is particularly ambitious, and well calculated to put the overall idea of extension under stress.

Wheeler actually examines two arguments, both based on experiments. The first, from Noë, relies on sensory substitution. Blind people fitted with apparatus that delivers optical data in tactile form begin to have what seems like visual experience (How do we know they really do? Plenty of scope for argument, but we’ll let that pass.) The argument is that the external apparatus has therefore transformed their phenomenal experience.

Now of course it’s uncontroversial that changing what’s around you changed the content of your experience, and changing the content changes your phenomenal experience. The claim here is that the whole modality has been transformed, and without a parallel transformation in the brain. It’s the last point that seems particularly vulnerable. Apparently the subjects adapt quickly to the new kit, too quickly for substantial ‘neural rewiring’, but what’s substantial in this context? There are always going to be some neural changes during any experience, and who’s to say that those weren’t the crucial ones?

The second argument is due to Kiverstein and Farina, who report that when macaques are trained to use rakes to retrieve food, the rakes are incorporated into their body image (as reflected in neural activity). This is easy enough to identify with – if you use a stick to probe the ground, you quickly start to experience the ‘feel’ of the ground as being at the end of the stick, not in your hand. Does it prove that your phenomenal experience is situated partly in the stick? Only in a sense that isn’t really the one required – we already felt it as being in the hand. We never experience tactile sensation as being in the brain: the anti-extension argument is merely that the brain is uniquely the substrate where it the feeling is generated.

Wheeler, rather anti-climatically but I think correctly, thinks neither argument is successful; and that’s another respect in which I think his paper represents the state of the extended mind thesis; both ambitious and unproven.
Worse than that, though, it illustrates the point which kills things for me; I don’t really care one way or the other. Shall we call these non-neural processes mental? What if we do? Will we thereby get a new insight into how mental processes work? Not really, so why worry? The thesis that experience is external in a deeper sense, external to my mind, is strange and mind-boggling; the thesis that it’s external in the flatly literal sense of having some of its works outside the brain is just not that philosophically interesting.

OK, it’s true that what we know about the brain doesn’t seem to explicate phenomenal experience either, and perhaps doesn’t even look like the kind of thing that in principle might do so. But if there are ever going to be physical clues, that’s kind of where you’d bet on them being.

Is phenomenal experience extended? Well, I reckon phenomenal experience is tied to the non-phenomenal variety. Red qualia come with the objective perception of red. So if we accept the extended mind for the latter, we should probably accept it for the former. But please yourself; in the absence of any additional illumination, who cares where it is?

Headless Consciousness

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Picture: Alva Noë. 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.