Archive for February, 2013

TithonusI have been reading about the Brain Preservation Foundation (BPF), which hopes that chemical and other methods, including a refined version of plastination, will enable brains to be preserved with such fidelity that memories, personality, and even identity can be preserved.

This may well seem reminiscent of the older cryogenic preservation projects which have not always had a good press over recent years, though they still continue to operate and indeed have refined their processes somewhat. But although the BPF also has a vision of bringing people back to life after their natural death, it is in many ways a different kettle of fish. It does not itself offer any kind of service but merely seeks to promote research, and it does not expect to see a practical system for many years. In addition, it makes its case and addresses objections in a commendably clear and thoughtful way – see for example this blog post by John M Smart, co-founder of the BPF. Perhaps this is partly also to do with its impressive panel of advisors, which includes such names as Chalmers, Seung, and Eagleman, to mention only a few.

I have some reservations about the project, which fall into several categories; there are general concerns about the practicality of preservation, doubts about personal identity, and doubts about the claimed social value of letting people have a prolonged or renewed life; but there are positive factors, too.

There are clearly a lot of technical issues involved in preserving a brain (often said to  be the most complex object in the universe) in all its detail, most of which I’m not competent to assess.  I think the main general practical issue (if this counts as practical) is that although you might get a quite different impression from the popular press, we still don’t really have a really clear idea of how the brain works – so in preserving it it’s hard to know whether we’re getting the right features. Clearly we would want the neuronal structure preserved in fine detail; but we keep finding out more about such matters as the incredibly complex sets of neurotransmitters that make the system work, about electrical interactions, and about the actual and possible role of astrocytes. If we’re optimistic we may feel we’re close to a working picture, but then we felt like that about genetics until the human genome was sequenced, and it’s now becoming increasingly clear that we didn’t know the half of it. Even without considering whether there might after all be something in the Penrose/Hameroff theory of unknown quantum mechanics operating in microtubules, or in similar ideas from outside the mainstream, there is a lot to think about. Of course the BPF can justly say that it is well aware of these issues , that  they only reinforce the need for more research, and that working on preservation could well be a good way of pushing that research forward.

I think it’s conceivable that there are also problems waiting to be discovered at a deeper level and that the brain can’t even theoretically be ‘frozen’ in working shape – particularly if mental activity turns out to be inherently dynamic. This could happen in a couple of general ways.  First, the brain could be like a zero-gravity box full of bouncing and colliding balls. You can’t halt the activity in such a box and restart at an arbitrary point: you have to start at the point where the balls were thrown in. Second, the brain could be like the old astronomical clocks which were geared together in such a way that they could not be reset; if they ever ran down and stopped, the only way to put them right again was to rebuild them. If either of these issues affects the brain, then it could not be restarted from its state at the last moment of consciousness, but only from some earlier state which might be a few minutes back, a few weeks, or in the worst case, the moment of birth! Now most of us would not mind losing just the last few minutes of our life if it meant we could then live on indefinitely, but even if that’s all it amounts to, recreating that earlier viable state from the later one we had preserved might be extremely difficult – if that’s the game we’re in.

The good news on that is that all the empirical evidence suggests there is no such problem. People have come back from states in which brain activity had apparently run down very close to zero without any major long-term problem: so we can probably afford to be optimistic that a stopped brain is not a dead brain ipso facto.

More of a problem (perhaps) is the BPF’s hope that preserving the brain might preserve personal identity. The philosophical literature on personal identity stretches back many centuries and I seem to remember that my own earlier self had some sophisticated views on it. As an undergraduate I think I developed a kind of morphic neo-nominalist position which dealt with nearly all the issues; but over the years I have become a caveman and my position now is more or less:  see this? this rock rock is rock what your problem? To put it another way I think brute physical identity is essential to personal identity.

I’m aware, of course, that the atoms and molecules of our body are constantly changing – but so what? Why should we think reality resides at the most micro level? Those particles barely have identities themselves; they’re more than half-way towards being mere mathematical constructions. People always say there’s a good chance we’re all breathing the odd molecule of oxygen that was once in the nostrils of Julius Caesar, but how would we know? Can you label a molecule? Can you recognise one? Can you even track where it goes? If I put three on a packing case, can you pick out the one you chose earlier? Isn’t it part of the deal that two protons have identical attributes, apart from their spatial co-ordinates? They’re not so much things as loci. Does talking about the same/different molecule, then, mean anything much? No, reality does not reside exclusively at the molecular level and I rest my case instead on the physical identity of certain neural structures, irrespective of their particle content. We are those critical neurons, I think.

Now you might think that the BPF is off to a flying start with me here, because instead of proposing to upload my mind onto magnetic media, they’re aiming to preserve the echt physical neurons. But I do not think they are optimistic about the prospects of literally restarting the self-same set of neurons: rather they adopt a ‘patternist’ view in which it’s the functional pattern of your mind that carries your identity. I doubt that: for one thing it seems to mean there could be as many of you as there are copies of the pattern. However, the strange thing is, I don’t think the majority of people will actually care: rightly or wrongly they’ll be just as happy with the prospect of a twin – really a kind of hyper-twin, far more like you than any real-life twin – as they would be with their own identity. Hey, they’ll say, I’m not really the same person I used to be ten years ago anyway, any more than you are the same person as that callow young morphic ne0-nominalist. Perhaps when we are in the unprecedented situation of being able to copy ourselves our conception of identity must naturally change and loosen, though as we ontologists say, the idea certainly gives me the willies.

There’s another deep problem in becoming immortal: I might run out. As it is, old people sometimes seem to repeat themselves or get stuck in a groove. Perhaps there comes a natural point when really you’ve said and thought everything important you’re ever going to say and think, and any further lifespan is just going to be increasingly stale repetition. Perhaps the price of acquiring a really fresh lot of mental plasticity is, frankly, being a new person. I have once or twice met older people who, while fit and mentally agile, seemed to feel that the job of their life was basically complete, and while they didn’t specially want to die, there wasn’t really that much detaining them any more, either. It’s a common observation, moreover, that old people sometimes seem to repeat themselves or get stuck in a groove.

I don’t really know how far the idea of people ‘running out’ is true or how far failing memory and appetite for fresh exploration might simply be the product of waning vigour and physical energy, of a kind the BPF might hope to rectify (if rectification is the appropriate term). However, it does seem likely that even if it were true different people would run out at different stages, and probably few of us have completely exhausted our potential by the time we’ve done three score and ten.  George Bernard Shaw took the view that three hundred years would be about the optimum lifespan, and it does feel like a comfortable benchmark: so even if there are natural limits to how far we should go on, it might be good to have the option of another couple of centuries.

That brings us on to the social benefits which the BPF suggests might accrue from having older minds around. They suggest that these older minds would be liberal and enlightened, and a force for progress, [Correction: John M. Smart has very courteously pointed out that the BPF doesn't suggest this at all. I don't quite know where I picked up the idea from, but I apologise for the error] which seems to fly in the face of many generations of experience, which is that old people tend to be increasingly conservative. Old scientists whose theories have been refuted don’t usually give them up: they merely die in due course, still protesting that they were right, and make way for a new generation.

If one comes from a culture that reveres certain ancestors, the the prospect of being able, as it were, to bring back Benjamin Franklin to put the Supreme Court right on a couple of points about the Constitution might look pretty appealing; but how many subjects are the oldies going to be experts on?  You may think now that you’re a pretty hip grandpa for understanding Facebook: in fifty years, are you going to have any grasp at all of what’s going on in a society mediated by electronic transactions on systems that haven’t even been conceived of yet?

The good news here is that if the BPF is right, future generations will be able to take the old people out and put them away again as required like library books. Your future life may turn out to be a series of disconnected episodes several hundred years apart. You may find yourself now and then waking up in worlds where your senatorial views on certain matters are valued, but don’t count on having the vote, if such a thing still exists in recognisable form.

All in all, it can’t be bad to reward research, and it certainly can’t be bad to think about the issues, which the BPF also does a good job on, so I wish them plenty of luck and success.

 

Dan Dennett confesses to a serious mistake here, about homuncular functionalism.

An homunculus is literally a “little man”. Some explanations of how the mind works include modules which are just assumed to be capable of carrying out the kind of functions which normally require the abilities of a complete human being. This is traditionally regarded as a fatal flaw equivalent to saying that something is done by “a little man in your head”; which is no use because it leaves us the job of explaining how the little man does it.
Dennett, however, has defended homuncular explanations in certain circumstances. We can, he suggests, use a series of homunculi so long as they get gradually simpler with each step, and we end up with homunculi who are so simple we can see that they are only doing things a single neuron, or some other simple structure, might do.

That seems fair enough to me, except that I wouldn’t call those little entities homunculi; they could better be called black boxes, perhaps. I think it is built into the concept of an homunculus that it has the full complement of human capacities. But that’s sort of a quibble, and it could be that Dennett’s defence of the little men has helped prevent people being scared away from legitimate “homuncular” hypotheses.

Anyway, he now says that he thinks he underestimated the neuron. He had been expecting that his chain or hierarchy of homunculi would end up with the kind of simple switch that a neuron was then widely taken to be; but he (or ‘we’, as he puts it) radically underestimated the complexity of neurons and their behaviour. He now thinks that they should be considered agents in their own right, competing for control and resources in a kind of pandemonium. This, of course, is not a radical departure for Dennett, harmonising nicely with his view of consciousness as a matter of ‘multiple drafts’.

It has never been really clear to me how, in Dennett’s theory, the struggle between multiple drafts ends up producing well-structured utterances, let alone a coherent personality, and the same problem is bound to arise with competing neurons. Dennett goes further and suggests, in what he presents as only the wildest of speculations, that human neurons might have some genetic switch turned on which re-enables some of the feral, selfish behaviour of their free-swimming cellular ancestors.

A resounding no to that, I think, for at least three reasons. First, it confuses their behaviour as cells, happily metabolising and growing, with their function as neurons, firing and transmitting across synapses. If neurons went feral it is the former that would go out of control, and as Dennett recognises, that’s cancer rather than consciousness. Second, neurons are just too dependent to strike out on their own; they are surrounded, supported, and nurtured by a complex of glial cells which is often overlooked but which may well exert quite a detailed influence on neuronal firing. Neurons have neither the incentive nor the capacity to strike out on their own. Third, although the evolution of neurons is rather obscure, it seems probable that they are an opportunistic adaptation of cells originally specialised for detecting elusive chemicals in the environment; so they may well be domesticated twice over, and not at all likely to retain any feral leanings. As I say, Dennett doesn’t offer the idea very seriously, so I may be using a sledgehammer on butterflies.

Unfortunately Dennett repeats here a different error which I think he would do well to correct; the idea that the brain does massively parallel processing. This is only true, as I’ve said before, if by ‘parallel processing’ you mean something completely different to what it normally means in computing. Parallel processing in computers involves careful management of processes which are kept discrete, whereas the brain provides processes with complex and promiscuous linkages. The distinction between parallel and serial processing, moreover, just isn’t that interesting at a deep theoretical level; parallel processing just a handy technique for getting the same processes done a bit sooner; it’s not something that could tell us anything about the nature of consciousness.

Always good to hear from Dennett, though. He says his next big project is about culture, probably involving memes. I’m not a big meme fan, but I look forward to it anyway.