Archive for November, 2006

Scanner The New Scientist‘s special 50th birthday issue has a number of interesting pieces: Roger Penrose on the nature of reality, Patricia Churchland on free will, and others. It also includes a piece from Nick Bostrom, Director of the Future of Humanity Institute at Oxford, offering an argument to show that it is highly likely that we are all, in fact, living in a computer simulation. I must say this is not among the most convincing arguments I have ever read. It starts with the assumption that in due course we shall have enough computer power and programming skill to create simulations of our ancestors and their world, with the simulated ancestors having full consciousness and phenomenal experience. Just a matter of computer power and programming skill, you see. Now these sim ancestors, being just like their creators, will in due course set up a simulation of their own ancestors: and they in turn will set up another. In time, we shall have an indefinitely long sequence of simulations all nested within each other. At that point we ask ourselves how likely it is that we are living in the first step of this process: ie the unsimulated real world. Because there is only one such world, but an indefinitely large number of simulated ones, it proves to be almost certain that we are in one of the simulations.

Even if we accept that consciousness is fully computational (hardly uncontroversial); even if we agree that there are no important differences between reality and a simulation; isn’t there something a little fishy about a simulation that contains a full copy of itself? How much of that computer power are we going to need? Could it be that to run an indefinitely large set of nested simulations, you would need an indefinitely large amount of capacity? I can’t help wondering whether the future of humanity is in the best possible hands here.

Our favourite question, “What is Consciousness?” is addressed by Paul Broks in a kind of futuristic fantasy; our hero is about to have himself uploaded into a new youthful body, though he hasn’t quite got the nerve to follow his daughter in getting the enhancements which would enable him to participate in the communal hive mind which is now available. I can’t say I blame him about that – have you seen the general public? Would you honestly want to share brains with them?

The general drift of the piece is that really the self is more like a bundle of tumbleweed than anything with a fixed core (though to make the analogy precise I think balls of tumbleweed would have to be constantly shedding and picking up new material); as Broks pithily sums it up: I realised I was talking to myself but no-one was listening.

Broks quotes a hoary old thought experiment about scanners (yes, I’m getting to the point at last) – apparently it was originated by Parfit. Imagine, it goes, we have a scanner which can register all your physical details and then reconstitute you somewhere else, with every detail the same. Your life continues, you retain your memories; you barely notice that anything has happened, perhaps. This shows that there is no solid core to your identity: if the physics and the functional systems are moved elsewhere, you just go with them, and nothing is left behind.

It seems like bad manners to question the premises of a thought experiment, but can we take for granted the possibility of these Star Trek style scanners? I think we are entitled to at least an outline of how they might work: unless they are clearly possible in principle the argument doesn’t get off the ground at all; yet I think there are some clear problems.

I think the idea is that the magic ‘fluence of the scanner, when in reconstitution mode, causes the right kinds of stuff to condense out of nothing, already in the right places and with the right qualities. Perhaps I’m resurrecting a medieval prejudice against action at a distance, but I don’t see how any conceivable apparatus could pull that off. There has to be some coherent causal chain which makes the right particles take up the right positions, which seem to imply that something has to intervene at those positions.

Perhaps that’s the wrong way of looking at it: perhaps the scanner actually somehow shoots protons, neutrons and electrons into the right places layer by layer: perhaps it does indeed scan across a cross-section at a time and build the reconstituted person from the feet up. It would need some clever mechanism to take account of the fact that real people aren’t made with a neatly laminated structure, and in fact it is going to have to be unbelievably accurate: given the importance of minute differences in the structure of neurons and the disposition of certain molecules within them, I suspect the tolerable error is actually zero. More awkwardly, it will have to allow for the fact that complex structures often require a particular asembly or construction sequence – this part has to be put in this way before that one goes in that way. If we start by scanning, let’s say, Captain Kirk’s feet into existence, the blood is going to start leaking out before we’ve done his shins, his tendons and muscles will lose their tension, and in general the whole thing will start falling apart in our hands. Perhaps, then, people get treated to the  grisly sight  of  Kirk’s skeleton being constituted first, to hold all the other bits up: but the scanner would have to  put in  some tendons and  connective tissue to hold the bones together: in fact, since  we can’t have working muscles until the circulation is going, we might need extra  ligatures or whatever which  don’t feature in the finished Kirk but get removed before the job is completed.  There’s still going to be a problem with  that damn blood: we need to put  all the vessels in place first and then fill them, which is tricky; and managing the filling and starting of the heart without a major problem will be difficult too.

But that won’t do at all, in any case, because we’re supposed to be reconstituting a dynamic system in full flight. It’s difficult enough to reconstitute a snooker table, but what we have to do is bring the table into existence as it was a moment after someone played a shot, with the balls already in motion in various directions. Kirk’s troublesome blood has to be flowing and all the right neurons have to be in mid-fire. The penalty if we can’t do that (and I don’t think we can) is that we have to reconstitute him in a slightly different, stable starting state, so that when Kirk is reconstituted he is unconscious and has suffered some loss of recent memory: when he comes round he doesn’t remember getting into the scanner or why he wanted to be scanned: in fact, the idea that this is the original Kirk, rather than a good copy, suddenly seems much less plausible.

It may be that getting used to computers has made us more ready to assume that reality is programmable, and hence to accept this kind of thought experiment. But the general idea has deeper roots. Even before consciousness became a fashionable topic, there was a long philosophical history of debating the nature of personal identity. One of the ideas that invariably got thrown out early in such discussions (and no doubt still does) was that our identity was, in the end, a matter of simple physical identity: this body really is me and vice versa. Physical identity is surely not the full story – but I wonder if it has been under-rated.

No more scanner arguments, please – unless they come with drawings and a technical specification.

William JamesThere’s a great collection of stuff about William James here, including the famous paper in which he introduced the concept of the ‘stream of consciousness’. That idea has been more influential in literature than psychology, perhaps, but James’ work enjoys tremendous respect among contemporary academics – much more than the works of some more recent thinkers whose ideas are tied to largely discredited theories.

Curiously, not all that many years after writing about the stream of consciousness, James produced a trenchant piece calling for the whole idea to be done away with. Consciousness, he wrote “is the name of a nonentity… a mere echo, the faint rumor left behind by the disappearing ‘soul’ upon the air of philosophy”.

A century later, this still sounds a perplexingly radical stance. James himself rather wearily observed that his view would take a good deal of explanation to make it plausible, something he did not feel he had achieved in a single paper. I think that’s pessimistic: the paper inevitably leaves a lot of metaphysical washing up to be done, but there’s nothing half-baked about the central point. The best way of grasping what James means is to take his point in a historical context, as the quotation above suggests.

Once, straightforward dualism was the unquestioned orthodoxy: there were physical objects and spiritual objects and a great gulf lay between the two. Souls basically did the perceiving and the physical world did the being-perceived. Over time, however, the gulf began to close and the two sides began to get closer. But although the prevailing orthodoxy became increasingly monist, a distinction was always maintained, eventually boiling down to the difference between subject and object: and that difference is, in a word, consciousness. Subjects possess this mysterious substance, objects do not.

James calls for a further step towards a purer monism. There is no substantial difference between subject and object, nor (this is a little more difficult to accept) between thoughts and things. It is all a matter of functional relationships. He offers the analogy of paint: when it’s in a tin, paint is clearly just a saleable commodity; when it’s on canvas as part of a painting, it represents things, it has meaning, and all the rest. But it’s still paint: it hasn’t become spooky magic meaning paint; it hasn’t been endowed with the miraculous stuff of subjectivity. It’s still paint. The only difference is that on the canvas it now stands in certain relationships to certain things (objects represented, people) which it didn’t while it was still in the tin.

Moreover, says James, so far as thoughts are concerned, aren’t imaginary objects fundamentally similar to real ones? People have difficulty in accepting that a fictional rose is really red, or a hallucinatory knife really sharp, but why? James isn’t arguing that imaginary objects are indistinguishable from real ones, but rather that they are distinguishable only through a difference in the relations between them: real knives cut real objects, while imaginary knives may or may not cut imaginary objects and don’t cut real ones at all. Real knives, we notice, have stable and predictable relations with other real objects – that’s what their reality amounts to, not a fundamental difference of substance.

Everything, it seems, reduces to experience, and in fact, if we reformulate our view of consciousness in those terms, it ceases to be problematic. So long as we recognise that it is a matter of relations within a monist world, we won’t get into trouble: let’s stop speaking of it as something in a world of its own.

I think that once you get over the initial strangeness of this view, it seems pretty logical. But I see two problems. The first is that James speaks as though the different relations between things in his accoung of the world were more or less arbitrary: as it happens, this thing has the relations which make it an idea or a subject, and these things haven’t. Surely it isn’t quite like that. Some of these things have qualities which enable them to enter into the required relations, and others don’t. A block of stone does not have the qualities needed to become a subject, still less a thought. On James’ account, much of the difficulty and many of the challenges arising from the issues of consciousness transfer to the task of describing what these qualities are: and one may legitimately suspect that the dualistic magic he has banished from his account is likely to pop up again in one form or another when that task is undertaken.

Second, I think there are basic problems in saying that imaginary things can be red or sharp in the same sense as real ones. What imaginary knives have is the property of being thought-of-as-sharp: but that’s clearly not the same as the property of being-sharp: real things can have the first in addition to, but distinct from, the second: in fact, they can have the property of being thought-of-as-sharp together with the property of not-really-being-sharp-at-all.

All the same, could it be true that we should do better to speak merely of experience, and stop talking about consciousness altogether?