Nicholas Humphrey is back with what he presents as a new attempt to knock that Hard Problem of qualia on the head once and for all. Soul Dust is not, however, a brand new theory: rather he has dusted down (or dusted up) the ideas he presented in Seeing Red, added some new points and a lot of persuasive advocacy, much of it in the form of quotes. He has many really good, interesting quotes, the sort that impel you to look up the original for more: but on the whole I think it was a mistake to invoke the ‘raindrops on roses and whiskers on kittens’ of The Sound of Music when extolling the splendiferous nature of a qualia-filled world.
The basic proposition of the book has two parts. The first is an account of perception and the self. Perception begins with a simple response to a stimulus – ‘redding’ if we’re seeing red. There are no qualia involved in that, but when we form a loop by perceiving our own redding it adds a special vividness which we project back on to the perceived object; seen as a property of the object, this reverberation in our brain (Humphrey speaks of ‘soul-hammering’) naturally seems somewhat mysterious: it’s like one of those paradoxical objects in an Escher picture (Humphrey uses as his example the 3D object made by Richard Gregory, which from one angle appears to be an impossible Penrose triangle). The looping also contributes to the construction of ‘thick time’, the perception of the present as something with significant duration rather than an infinitesimal line dividing past and present.
The enchanted quality of experience sheds the same illusory magic on the perceiving self, and by extension on the thinking Ego which goes with it. All this is why the world seems so worth experiencing and why we seem to ourselves so well worth preserving: a qualia-free zombie wouldn’t have any great relish in life nor any particular reason to fear death. That’s the second part of the case: this business of ‘artificial’ qualic impressions has come about through evolution because the extra zest it confers gives the possessor of qualia a survival edge over zombie counterparts.
The book is an engaging and persuasive read: you feel you’ve spent some time in friendly conversation with a very civilised and erudite man who has seen deeply into some of the issues. But there are a few problems.
The first is that the book isn’t really about qualia at all. Humphrey, reasonably enough perhaps, dismisses the idea of ineffable qualia that can’t be described and play no causal role in the world. Since he wants to give an evolutionary explanation, he has to take this stance: ineffable qualia couldn’t have survival value. But if they ain’t ineffable, they ain’t really qualia, and what we’re talking about ain’t really the Hard Problem. It’s the ineffability that’s hard to explain; take that away and explaining why sensations are vivid may be non-trivial, but it’s part of the Easy Problem. I’m not altogether sure he realises it, but Humphrey has pitched his camp with Dennett and accordingly all he is really entitled to say is “what qualia?”.
Although they’re not ineffable, Humphrey still wants his qualia to be illusions, a magic lantern show rather than a radar system. Why is that? If our perceptions are not of ineffable qualia, can’t they just be of real qualities of actual things? One reason Humphrey wants them to be illusions is that he wants to use the fact to validate that much-quoted phraseology about there being “something is it like” to experience things: the thing it’s like can be the thing itself. But also lurking somewhere in the back of Humphrey’s mind is, I suspect, that terrible old argument from error: because some of our perceptions are not of real things, none of them are – they’re all of proxies in our heads.
So everything that makes life seem worthwhile is actually an illusion? It’s a grim conclusion to reach, though Humphrey doesn’t seem to read it that way: he talks about the delight of experience and the wonder of the world as though he hadn’t begun by insisting that all these things are confidence tricks, quite false in fact. If Humphrey takes his own views seriously, he must be forced to conclude that in sober fact the zombies would be right: there actually is no particular reason to go on living and everything we value is in fact worthless. In fact, perhaps he does realise this, because he closes with an examination of the reasons why we go on living in the face of our undeniable mortality: not the actual reasons why we should go on living, but the deluded considerations that stop us topping ourselves immediately. He concludes that belief in an afterlife, supported by such things as our experience of waking every day, as if from death, is a natural part of the human outlook and the main thing that keeps most of us going. I think in fact that the majority of people, faced with the fact of eventual death, simply don’t waste time worrying about something they can’t change. Humphrey seems to think that a natural reaction to the inevitability of eventual death is immediate suicide: that might be one emotional reaction but I think to most people the lack of logic in bringing forward the very thing you fear is too salient to make that an attractive course. Myself I think it’s possible that if we attain sufficient maturity we might come to realise that one good life is enough. You don’t have to be a pessimist or severely depressed to think that rightly understood, the law that everything has its termination amounts to a promise, not a threat.
What about the second point, that qualia are here because they have positive survival value? I like the idea of looking for an evolutionary explanation, but I don’t think Humphrey ever makes this really convincing. The main argument seems to be that the extra pleasure given by qualia means we’re better motivated than zombies would be, and pay more attention. Yet there are surely many unpleasant and repulsive qualia; logically one might suppose as many of those as pleasant, attractive ones. Malthus tells us that most animals naturally live on the brink of starvation; having their constantly frustrated desire for food intensified doesn’t seem as obviously a good thing for them as it might be for us well-fed historical anomalies. Above all, aren’t qualia distracting? Isn’t it all too likely that while the qualophile animals are admiring the sunset they are more likely to be caught by the sabre-toothed tiger?
I think there is actually a potential argument here that Humphrey doesn’t use. Most animals get by very largely on instinct and other relatively hard-wired behaviour; only humans have really broken free to do whatever their rational deliberations – or their irrational whims – suggest to them. It could be argued that humans need qualia exactly to make the traditional sensory rewards for ‘good’ behaviour more potent in compensation for our greater ability to over-ride them. We need food to be more exciting and sex sexier to make us attend sufficiently to the basic biological imperatives instead of simply starving to death while reading or playing computer games (or committing suicide out of misplaced philosophical angst). That would make a certain kind of sense, anyway.
It may sound from the foregoing as if I radically disagree with everything Humphrey says, but that’s not the case at all: the book is a good rational effort in the right area, and it expresses some complex insights with marvellous lucidity. But (alas, how many times have I said this over the years?) it’s not quite the Answer.