Archive for May, 2012

UnityThe unity of the soul is an ancient doctrine from which we have inherited a strong belief in the unity of consciousness. In certain lights this assumption of unity seems unquestionable, but it has actually been a continual problem; it could almost be argued that the history of understanding the mind has been a history of giving up on unity.

Like other persuasive doctrines that have turned out to be problematic in the long run, we can trace this one back to Aristotle, but it is tied in to a widely-held set of scholastic/ancient ideas about metaphysics. I believe the argument runs more or less like this: the soul is not physical, therefore it lacks extension (which is a physical property); if it lacks extension it necessarily lacks parts, and if it lacks parts it must be single and unified. The soul is a substance, in the old philosophical sense of something incapable of being analysed or broken down. Substances in this sense used to be considered necessary building blocks of reality, required in order to have a secure ontological foothold.  Otherwise the process of analysis would be bottomless and unending, and nothing would ever be completely clarified, which would be intolerable (although I notice contemporary physics seems to tolerate a position not altogether unlike this).  Readers may well by now feel parts of their own souls waving urgent hands to attract attention to a host of salient objections, but let’s avoid getting bogged down in this treacherous territory and move on a bit.

Descartes, say what you will about his dualism, effected a radical change for the better when he restricted the interventions of the soul to the pineal gland: on his view it did its stuff there and the rest of the body worked like a machine, according to the same physical laws as any inanimate stuff. Until then it had been largely assumed that the soul directly activated the body without needing any kind of transmission mechanism. Now I say ‘until then’, but the remarkable fact is that people went on thinking that way for a long time afterwards. As late as 1850, Helmoltz’s measurement of the speed of nerve impulses was resisted by some on the grounds that the vital impulse must act throughout the body simultaneously. When your arm moved, it was because you wanted it to, and it, as part of you, wanted to too.  I believe there was a school of thought that held out for a middling point of view, accepting that in principle the brain controlled the body by nerve impulses, but confidently expecting that they would be too blindingly fast to ever be measured. This, of course, proved to be quite wrong, but the nineteenth-century debate is in some ways quite reminiscent of the more recent discussion of Libet. Muller and others thought Helmholtz must be wrong because he was introducing a delay between will and act; people suppose Libet must be wrong because he introduces a delay between deciding to act and awareness. All such delays are intolerable if we insist on the absolute unity of the conscious mind because you can’t have a delay between a thing and itself.

Another prominent example of the problems flowing from unity is the vexed issue of the binding problem. Given that sensory inputs come in by different pathways at different speeds and get processed in different ways in different parts of the brain, how is it we end up with a smoothly integrated picture of reality which assigns the right qualities to the right objects and unrolls steadily in real time without jumps, pauses, or lipsynch errors? There are various ways, more or less satisfactory or problematic, in which the brain might ensure everything is properly put together when it arrives in consciousness, but if we’re not assuming consciousness is a single united destination, the problem wouldn’t arise in the first place.

Perhaps, though, the binding problem gives us a clue about why unity seems so undeniable – because the contents of consciousness look united. Isn’t that it?

Well, sort of, but when I sit down and conscientiously introspect, I don’t really detect a lot of unity. At the moment I have strings of explicit words running through my mind a moment before I type them: I moment ago as I sat in uffish thought, I had thoughts about the same subject which were wordless. Half an hour ago I wasn’t thinking about anything at all, though I was certainly conscious, and a bit before that I was largely absorbed by experiencing the taste of scrambled egg. An hour before that I was dreaming and some time before that in a blank state of which I can’t say for sure whether I remember it or not.

It’s worse than that, because at all these times there were also things in the penumbra of my mind which I was aware, or perhaps only pre-aware or potentially aware of. Hume famously said that when he looked into his mind he found only a bundle of sensations; but how simple it would be if the sensations were really always bundled; if they were always of the same broad kind; and if they were all merely sensations, instead of including bits of broken intentionality, fragments of half-or potentially meaningful intimations, things that might be the phenomenally detectable end of affordances, incipient recognitions and implicatures and an exquisitely ineffable and shadily located intimation that there may soon be the emergence of what we can call a gut feeling finely balanced on the cusp between the affective and the merely digestive. A bundle? Really a heap, or even a cloud, would be far more orderly and unified than my subjective experience.

What does bind things together is a kind of bird’s nest framework of memory linking now to then, and then to some other experience, and so on; but this is not all that useful. For one thing these linkages are loose – what they provide is the kind of tangled and ad hoc unity the cables behind my stereo have achieved unbidden – and they are fallible, not part of the essence of consciousness. I see nothing absurd about the idea of my  having moments of consciousness which are neither remembered nor involve remembering.

Yet even so I find it intuitively impossible to abandon the idea of some unity somewhere, even if I can’t quite put my finger on it at the moment. Things would be so much easier if we didn’t exist, but there we are.

 

The Observer has a discussion between Tallis and Eagleman, Eagleman representing neural reductionism and Tallis speaking for a more traditional view of mind and brain.

Although it’s worth reading, it turns out a slightly inconclusive encounter. Perhaps on this occasion you’d give Tallis a points victory because he does seem to be looking for a fight, whereas Eagleman is in rather cautious form. They circle each other but never quite identify a proposition which sums up their disagreement clearly enough to get things going.

What seems to emerge is a kind of agreement that mental activity needs to be addressed on more than one level of explanation, with the two antagonists merely giving a different balance of emphasis. This certainly understates the real disagreement between the two.

I think it probably is the case that nearly everyone grants the need for more than one level of explanation. There are those who would say the correct top level is the cosmos itself and that individual consciousness expresses a universal entity.  Not quite as high-level as that we surely need to address consciousness on the level of its explicit and social content; we could call this the ‘home’ level because it is sort of where we live, where we actually experience the world. Most would agree that there are levels of unconscious operation that are also a necessary part of the picture; not many people would say that the structure of the brain and its component neurons tell us nothing; and a majority nowadays would agree that there is ultimately a story at the classical molecular level which, though vastly complex, cannot  be ignored. Some say even this is not enough and that consciousness cannot be understood without giving quantum mechanics, or some as-yet-unknown lower level theory, a crucial role.

Only a very hard-line reductionist would say we only need one of these levels: it’s generally accepted that there are interesting things to be said on several of them which simply cannot be addressed at other levels. What mainly emerges here is Tallis’ defence of the ‘home’ level against Eagleman’s contention that we pay it too much attention and that for many purposes, including our treatment of crime and punishment, we should dethrone it. Intuitively, the motives for Tallis’ incredulity are pretty clear: wouldn’t it be weird if we had developed the apparatus of thought and consciousness and yet it had no important impact on our behaviour? Don’t we just know that discussion and conscious thought ultimately shape what we do, even if our behaviour is sometimes nudged in different directions by factors we’re not aware of?

Yet there is something deeply unsatisfactory about the whole idea of different levels of explanation, isn’t there? How can one reality require half-a-dozen different accounts? It seems a distressingly messy and arbitrary kind of way for the world to be set up, and certainly we greet any successful reduction of higher level entities to lower level ones as a valuable explanatory achievement. So it’s not hard to sympathise with Eagleman’s desire to emphasise the role of levels below consciousness either.

Generally speaking it seems that the lower the level of our explanation the better, as though ultimate reality resides at the lowest micro level we can get to. We always celebrate reductions, not elaborations. Yet there have been some rebellious attempts to push things the other way through ideas such as emergence and embodiment, which claim the whole can be more important than the parts. I notice myself that things seem to come most clearly into focus at or slightly below the home level: if we go far above or below that we start to get into regions where we have to deal in probabilities or slightly fuzzy concepts. Most notably there don’t seem to be identities at other levels in quite the sharp way there are on the home level. Even molecules are interchangeable: they tell us that it’s almost certain we’re breathing at least one atom from the oxygen previously breathed by Julius Caesar, but how could you possibly tell? You can’t label an atom. Another one of the same kind is distinguishable only by where it is. When we go further down even spatial positions start to get a bit smudged. Equally if we start going up the chain we can only draw slightly fuzzy conclusions about what my family, or the society I live in, thinks or does. This might be a reason to think that real reality is around the home level – or it might a reason to think that the whole business of levels simply flows from my restricted viewpoint and limited understanding.

Perhaps, if my brain were capable of holding it, there is a view on which all the levels could come together. After all, I go on thinking about temperature even though I know it is only molecular motion: perhaps in the end we’ll find a way of thinking about the different aspects of mental activity which brings them together without eliminating anything. Perhaps then it might become clear that Eagleman and Tallis don’t really disagree at all. I wouldn’t put any money on that, though.