Tag Archives: reduction

Mary and the Secret Stones

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Adam Pautz has a new argument to show that consciousness is irreducible (that is, it can’t be analysed down into other terms like physics or functions). It’s a relatively technical paper – a book length treatment is forthcoming, it seems – but at its core is a novel variant on the good old story of Mary the Colour Scientist. Pautz provides several examples in support of his thesis, and I won’t address them all, but a look at this new Mary seems interesting.

Pautz begins by setting out a generalised version of how plausible reductive accounts must go. His route goes over some worrying territory – he is quite Russellian, and he seems to take for granted the old and questionable distinction between primary and secondary qualities. However, if the journey goes through some uncomfortable places, the destination seems to be a reasonable place to be. This is a  moderately externalist kind of reduction which takes consciousness of things to involve a tracking relation to qualities of real things out there. We need not worry about what kinds of qualities they are for current purposes, and primary and secondary qualities must be treated in a similar way. Pautz thinks that if he can show that reductions like this are problematic, that amounts to a pretty good case for irreducibility.

So in Pautz’s version, Mary lives on a planet where the outer surfaces of everything are black, grey, or white. However, on the inside they are brilliantly coloured, with red, reddish orange, and green respectively. All the things that are black outside are red inside, and so on, and this is guaranteed by a miracle ‘chemical’ process such that changes to the exterior colour are instantly reflected in appropriate changes inside. Mary only sees the outsides of things, so she has never seen any colours but black, white and grey.

Now Mary’s experience of black is a tracking relation to black reflectances, but in this world it also tracks red interiors. So does she experience both colours? If not, then which? A sensible reductionist will surely say that she only experiences the external colour, and they will probably be inclined to refine their definitions a little so that the required tracking relation requires an immediate causal connection, not one mediated through the oddly fixed connection of interior and exterior colours. But that by no means solves the problem, according to Pautz. Mary’s relation to red is only very slightly different to her relation to black. Similar relations ought to show some similarity, but in this case Mary’s relation to black is a colour experience, whereas her relation to red, intrinsically similar, is not a colour experience – or an experience of any kind! If we imagine Martha in another world experiencing a stone with a red exterior, then Martha’s relation to red and Mary’s are virtually identical, but have no similarity whatever. Suppose you had a headache this morning, suggests Pautz, could you then say that you were in a nearly identical state this afternoon, but that it was not the state of experiencing a headache; in fact it was no experience at all (not even, presumably, the experience of not having a headache).

Pautz thinks that examples of this kind show that reductive accounts of consciousness cannot really work, and we must therefore settle for non-reductive ones. But he is left offering no real explanation of the relation of being conscious of something; we really have to take that as primitive, something just given as fundamental. Here I can’t help but sympathise with the reductionists; at least they’re trying! Yes, no doubt there are places where explanation has to stop, but here?

What about Mary? The thing that troubles me most is that remarkable chemical connection that guarantees the internal redness of things that are externally black. Now if this were a fundamental law of nature, or even some logical principle, I think we might be willing to say that Mary does experience red – she just doesn’t know yet (perhaps can never know?) that that’s what black looks like on the inside. If the connection is a matter of chance, or even guaranteed by this strange local chemistry, I’m not sure the similarity of the tracking relations is as great as Pautz wants it to be. What if someone holds up for me a series of cards with English words on one side? On the other, they invariably write the Spanish equivalent. My tracking relation to the two words is very similar, isn’t it, in much the same way as above? So is it plausible to say I know what the English word is, but that my relation to the Spanish word is not that of knowing it – that in fact that relation involves no knowledge of any kind? I have to say I think that is perfectly plausible.

I can’t claim these partial objections refute all of Pautz’s examples, but I’m keeping the possibility of reductive explanations open for now.

 

Tallis vs Eagleman

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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.