Motus Mentis

Sam Harris has just published a follow-up post about the mystery of consciousness. He is frankly pessimistic that any conceivable advances in neuroscience — and he is a neuroscientist — can ever lead us to the bridge we seek between our ever-richer model of the physical world and an understanding of subjective awareness:

It is easy to see how the contents of consciousness might be understood at the level of the brain. Consider, for instance, our experience of seeing an object””its color, contours, apparent motion, location in space, etc. arise in consciousness as a seamless unity, even though this information is processed by many separate systems in the brain. Thus when a golfer prepares to hit a shot, he does not first see the ball’s roundness, then its whiteness, and only then its position on the tee. Rather, he enjoys a unified perception of a ball. Many neuroscientists believe that this phenomenon of “binding’ can be explained by disparate groups of neurons firing in synchrony. Whether or not this theory is true, it is perfectly intelligible””and it suggests, as many other findings in neuroscience do, that the character of our experience can often be explained in terms of its underlying neurophysiology. However, when we ask why it should be “like something’ to see in the first place, we are returned to the mystery of consciousness in full.

For these reasons, it is difficult to imagine what experimental findings could render the emergence of consciousness comprehensible. This is not to say, however, that our understanding of ourselves won’t change in surprising ways through our study of the brain. There seems to be no limit to how a maturing neuroscience might reshape our beliefs about the nature of conscious experience. Are we fully conscious during sleep and merely failing to form memories? Can human minds be duplicated or merged? Is it possible to love your neighbor as yourself? A precise, functional neuroanatomy of our mental states would help to answer such questions””and the answers might well surprise us. And yet, whatever insights arise from correlating mental and physical events, it seems unlikely that one side of the world will be fully reduced to the other.

While we know many things about ourselves in anatomical, physiological, and evolutionary terms, we do not know why it is “like something’ to be what we are. The fact that the universe is illuminated where you stand””that your thoughts and moods and sensations have a qualitative character””is a mystery, exceeded only by the mystery that there should be something rather than nothing in this universe. How is it that unconscious events can give rise to consciousness? Not only do we have no idea, but it seems impossible to imagine what sort of idea could fit in the space provided. Therefore, although science may ultimately show us how to truly maximize human well-being, it may still fail to dispel the fundamental mystery of our mental life. That doesn’t leave much scope for conventional religious doctrines, but it does offer a deep foundation (and motivation) for introspection. Many truths about ourselves will be discovered in consciousness directly, or not discovered at all.

For all this gloom, though, about the possibility of our ever understanding the nature of consciousness, Dr. Harris does not seem to doubt that consciousness is indeed, somehow, the product of the living, physical brain. (It certainly isn’t as if he thinks human consciousness is a splinter of the mind of God, or something.)

If this is true, then — that in some way our conscious minds really do arise from, and depend for their existence upon, the workings of our material brains — then I have to ask once again, as I always do when this subject comes up: why should our inability, as yet, even to imagine what a true theory of consciousness might look like be taken as evidence that such a theory will never be forthcoming? If what appears to be happening really is what is actually happening — that a process in the physical world gives rise to a phenomenon we can all observe — why should we be convinced that we shall never be able to explain it? Nobody had the slightest inkling how to answer the riddles that tormented the physicists of the late 19th century until the radical — and, what is more to the point, breathtakingly, unimaginably counterintuitive — insights of Einstein and his contemporaries shattered and reconstructed the intellectual landscape. It was Einstein who, when all around him were baffled and losing hope, did exactly what Dr. Harris is calling for here: he imagined “what sort of idea could fit in the space provided”.

I understand the argument that in principle we could describe the working of the brain down to a fare-thee-well and still only have physical, not subjective, facts in hand. But so far, we are nowhere near even to understanding the correlates of consciousness in exhaustive microscopic, neurological, chemical, quantum-mechanical, or computational detail. From an engineering, heuristic perspective, that’s the least we need: to be able to identify with predictive certainty exactly what physical states, processes, and above all, changes correlate precisely with particular effects in consciousness. Is that enough? No, and that’s the point that all skeptics raise: you can have all that, and you still haven’t said what consciousness is, or why those correlations are what they are. But it will only be when you have reduced the facts, the correlations, down to that level of detail — when you can say this bit of matter entering exactly this state, or this pattern of activity across the whole brain, is both necessary and sufficient to cause this effect in consciousness — that you will have focused the problem to the point where some indefatigable genius, some Einstein of the mind, may be able to insert his crowbar.

Can I know this will ever happen? No, of course not. Perhaps I’m too optimistic. Our capacity to understand the world may limited in ways we can never even conceive of, and the answer to this riddle may simply be beyond our powers of imagination. But by the same token, nobody can possibly know that it won’t.