Where am I?

brain-implantA treat for lovers of bizarre thought experiments, Rick Grush’s paper Some puzzles concerning relations between minds, brains, and bodies asks where the mind is, in a sequence of increasingly weird scenarios. Perhaps the simplest way into the subject is to list these scenarios, so here we go.

Airhead. This a version of that old favourite, brain-in-a-vat. Airhead’s brain has been removed from its skull, but every nerve ending is supplied with little radio connectors that ensure the neural signals to and from the brain continue. The brain is supplied with everything it needs, and to Airhead everything seems pretty normal.

Rip. A similar set-up, but this time the displacement is in time. Signals from body to brain are delayed, but signals in the opposite direction are sent back in time (!) by the same interval, so again everything works fine. Rip seems to be walking around three seconds, or why not, a thousand years hence.

Scatterbrain. This time the brain is split into many parts and the same handy little radio gizmos are used to connect everything back up. The parts of the brain are widely separated. Still Scatterbrain feels OK, but what does the thought ‘I am here’ even mean?

Raid. We have two clones, identical in every minutest detail; both brains are in vats and both are connected up to the same body – using an ‘AND’ gate, so the signal passes on only if both brains send the same one (though because they are completely identical, they always will anyway). Two people? One with a backup?

Janus. One brain, two bodies, connected up in the way we’re used to by now; the bodies inhabit scrupulously identical worlds: Earth and Twin Earth if you like.

Bourdin. This time we keep the identical bodies and brains, wire them up, and let both live in their identical worlds. But of course we’re not going to leave them alone, are we? (The violence towards the brain displayed in the stories told by philosophers of mind sometimes seems to betray an unconscious hatred of the organ that poses such intractable questions – not that Grush is any worse than his peers.) no; what we do is switch signals from time to time, so that the identical brains are linked up with first one, then the other, of the identical bodies.

Theseus. Now Grush tells us things are going to get a little weird… We start with the two brains and bodies, as for Bourdin, and we divide up the brains as for Scatterbrain. Now we can swap over not just whole brains, but parts and permutations. Does this create a new individual every time? If we put the original set of disconnected brain parts back together, does the first Theseus come back, or a fresh individual who is merely his hyper-identical twin?

Grush tests these situations against a range of views, from ‘brain-lubbers’ who believe the mind and the brain are the same thing, through functionalists of various kinds, to ‘contentualists’ who think mind is defined by broad content; I think Grush is inventing this group, but he says Dennett’s view of the self as ‘a centre of narrative gravity’ is a good example. It’s clearly this line of thinking he favours himself, but he admits that some of his thought experiments throw up real problems, and in the end he offers no final conclusion. I agree with him that a discussion can have value without being tied to the defence of a particular position; his exploration is quite well done and did suggest to me that my own views may not be quite as coherent as I had supposed.

He defends the implausibility of his scenarios on a couple of grounds. We need to test our ideas in extreme circumstances to make sure they are truly getting the fundamentals and setting aside any blinkers we may have on. Physical implausibilities may be metaphysically irrelevant (nobody believes I’m going to toss a coin and get tails 10,000 times in a row, but nobody sees a philosophical problem with talking about that case).  To be really problematic, objections would have to raise nomological or logical impossibilities.

Well, yes but… All of the thought experiments rely on the idea that nerves work like wires, that you can patch the signal between them and all will be well. The fact that that instant patching of millions of nerves is not physically possible even in principle may not matter. But it might be that the causal relations have to be intact; Grush says he has merely extended some of them, but picking up the signal and the relaying it is a real intervention, as is shown when later thought experiments use various kinds of switching. It could be argued that just patching in radio transmitters destroys the integrity of the causality and turns the whole thing into a simulation from the off.

The other thing is, should we ask where the mind is at all? Might not the question just be a category mistake? There are various proxies for the mind that can be given locations, but the thing itself? Many years ago, on the way to nursery, my daughter told me a story about a leopard. What is the location of that story? You could say it is the streets where she told it; you could say it is in the non-existent forest where the leopard lived. You could say it is in my memory, and therefore maybe in my brain in some sense. But putting the metaphors aside, isn’t it plausible that location is a property these entities made of content just don’t have?

 

Metempsychotic Solipsism

metemsolipMy daughter Sarah (who is planning to study theology) has insisted that I should explain here the idea of metempsychotic solipsism, something that came up when we were talking about something or other recently.

Basically, this is an improved version of reincarnation. There are various problems with the theory of reincarnation. Obviously people do not die and get born in perfect synchronisation, so it seems there has to be some kind of cosmic waiting room where unborn people wait for their next turn. Since the population of the world has radically increased over the last few centuries, there must have been a considerable number of people waiting – or some new people must come into existence to fill the gaps. If the population were to go down again, there would be millions of souls left waiting around, possibly for ever – unless souls can suddenly and silently vanish away from the cosmic waiting room. Perhaps you only get so many lives, or perhaps we’re all on some deeply depressing kind of promotion ladder, being incentivised, or possibly punished, by being given another life. It’s all a bit unsatisfactory.

Second, how does identity get preserved across reincarnations? You palpably don’t get the same body and by definition there’s no physical continuity. Although stories of reincarnation often focus on retained memories it would seem that for most people they are lost (after all you have to pass through the fetal stage again, which ought to serve as a pretty good mind wipe) and it’s not clear in any case that having a few memories makes you the same person who had them first. A lot of people point out that ongoing physical change and growth mean it’s arguable whether we are in the fullest sense the same person we were ten years ago.

Now, we can solve the waiting room problem if we simply allow reincarnating people to hop back and forth over time. If you can be reincarnated to a time before your death, then we can easily chain dozens of lives together without any kind of waiting room at all. There’s no problem about increasing or reducing the population: if we need a million people you can just go round a million times. In fact, we can run the whole system with a handful of people or… with only one person! Everybody who ever lived is just different incarnations of the same person! Me, in fact (also you).

What about the identity problem? Well, arguably, what we need to realise is that just as the body is not essential to identity (we can easily conceive of ourselves inhabiting a different body), neither are memories, or knowledge, or tastes, or intelligence, or any of these contingent properties. Instead, identity must reside in some simple ultimate id with no distinguishing characteristics. Since all instances of the id have exactly the same properties (none) it follows by a swoosh of Leibniz’s Law (don’t watch my hands too closely) that they are all the same id. So by a different route, we have arrived at the same conclusion – we’re all the same person! There’s only one of us after all.

The moral qualities of this theory are obvious: if we’re all the same person then we should all love and help each other out of pure selfishness. Of course we have to take on the chin the fact that at some time in the past, or worse, perhaps in the future, we have been or will be some pretty nasty people. We can take comfort from the fact that we’ve also been, or will be, all the best people who ever lived.

If you don’t like the idea, send your complaints to my daughter. After all, she wrote this – or she will.

Experimental Identities

dereta parboIn this discussion over at Edge, Joshua Knobe presents some recent findings of experimental philosophy on the problem of personal identity. Experimental philosophy, which sounds oxymoronic,  is the new and trendy (if it still is?) fashion for philosophising rooted in actual experiments, often of a psychological nature.  The examples I’ve read have all been perfectly acceptable and useful – and why shouldn’t they be? No one ever said philosophy couldn’t be inspired by science, or draw on science. In this case, though, I was not altogether convinced.

After a few words about the basic idea of experimental philosophy, Knobe introduces a couple of examples of interesting problems with personal identity (as he says, it is one of the longer-running discussions in philosophy of mind, with a much older pedigree than discussions of consciousness). His first example is borrowed from Derek Parfit:

Imagine that Derek Parfit is being gradually transformed molecule by molecule into Greta Garbo. At the beginning of this whole process there’s Derek Parfit, then at the end of the whole process it’s really clear that Derek Parfit no longer exists. Derek Parfit is gone. Now there’s Greta Garbo. Now, the key question is this:  At what point along this transformation did the change take place? When did Derek cease to exist and when did Greta come to exist? If you just have to reflect on this question for a while, immediately it becomes clear that there couldn’t be some single point — there couldn’t be a single second, say – in which Derek stops existing and Greta starts existing. What you’re seeing is some kind of gradual process where, as this person becomes more and more and more different from the Derek that we know now, it becomes less and less right to say that he’s Derek at all and more and more right to say that he is gone and a completely other person has come into existence.

I’m afraid this doesn’t seem a great presentation of the case to me. In the first place, it’s a text-book case of begging the question. The point of the thought-experiment is to convince us that Parfit’s identity has changed, but we’re just baldly told that it has, right from the off. We should be told that Parfit’s body is gradually replaced by Garbo’s (and does Garbo still exist or is she gradually eroded away?), then asked whether we still think it’s Parfit when the process is complete. I submit that, presented like that, it’s far from obvious that Parfit has become Garbo (especially if Garbo is still happily living elsewhere); we would probably be more inclined to say that Parfit is still with us and has simply come to resemble Garbo – resemble her perfectly, granted – but resemblance is not identity.

Second: molecule by molecule? What does that even mean? Are we to suppose that every molecule in Parfit has a direct counterpart in Garbo? If not, how do we choose which ones to replace and where to put them? What is the random replacement of molecules going to do to Parfit’s DNA and neurotransmitters, his neurons, his capillaries and astrocytes? Long before we get to the median sage Parfit is going to be profoundly dead, if not reduced to soup. I know it may seem like bad manners to refuse the terms of a thought experiment; magic is generally OK, but what you can’t do is use the freedom it provides to wave away some serious positions on the subject – and it’s a reasonable position on personal identity to think that functional continuity is of the essence.  ‘Molecule by molecule’ takes it for granted that Parfit’s detailed functional structure is irrelevant to his identity.

In fairness we should probably cut Knobe a bit of slack, since circumstances required a short, live exposition. His general point is that we can think of our younger or older selves as different people. In an experiment where subjects were encouraged to think either that their identities remained constant, or changed over time, the ones encouraged to believe in change were happier about letting a future payment go to charity.

Now at best that tells us how people may think about their personal identity, which isn’t much help philosophically since they might easily be flat wrong. But isn’t it a bit of a rubbish experiment, anyway? People are very obliging; if you tell them to behave in one way and then, as part of the same experiment, give them an opportunity to behave that way, some of them probably will; that gives you no steer about their normal behaviour or beliefs.  There’s plenty of evidence in the form of the massive and prosperous pensions and insurance industries that people normally believe quite strongly in the persistence of their identity.

But on top of that, the results can be explained without appealing to considerations of identity anyway. It might be that people merely think: well, my tastes, preferences and circumstances may be very different in a few years, so no point in trying to guess what I’ll want then without in any way doubting that they will be the same person. Since this is simpler and does not require the additional belief in separate identities, Occam’s Razor tells us we should prefer it.

The second example is in some ways more interesting: the aim is to test whether people think emotional, impulsive behaviour, or the kind that comes from long calm deliberation, is more truly reflective of the self. We might, of course, want to say neither, necessarily. However, it turns out that people do not consistently pick either alternative, but nominate as the truest reflection of the person whichever behaviour they think is most virtuous. People think the true self is whichever part of you is morally good.

That’s interesting; but do people really think that, or is it that kindness towards the person in the example nudges them towards putting the best interpretation possible on their personhood – in what is actually an indeterminate issue? I think the latter is almost certainly the case. Suppose we take the example of a man who when calm (or when gripped by artistic impulses) is a painter and a vegetarian; when he is seized by anger (or when thinking calmly about politics) he becomes a belligerent genocidal racist. Are people going to say that Hitler wasn’t really a bad man, and the Nazism wasn’t the true expression of his real self; it was just those external forces that overcame his better nature? I don’t think so, because no-one wants to be forgiving towards Adolf. But towards an arbitrary person we don’t know the default mode is probably generosity.

I dare say this is all a bit unfair and if I read up the experiments Knobe is describing I should find them much better justified than I suppose; but if we’re going to have experiments they certainly need to be solid.

Experience and Autonomy

angelanddevilTom Clark has an interesting paper on Experience and Autonomy: Why Consciousness Does and Doesn’t Matter, due to appear as a chapter in Exploring the Illusion of Free Will and Responsibility (if your heart sinks at the idea of discussing free will one more time, don’t despair: this is not the same old stuff).

In essence Clark wants to propose a naturalised conception of free will and responsibility and he seeks to dispel three particular worries about the role of consciousness; that it might be an epiphenomenon, a passenger along for the ride with no real control; that conscious processes are not in charge, but are subject to manipulation and direction by unconscious ones; and that our conception of ourselves as folk-dualist agents, able to step outside the processes of physical causation but still able to intervene in them effectively, is threatened. He makes it clear that he is championing phenomenal consciousness, that is, the consciousness which provides real if private experiences in our minds; not the sort of cognitive rational processing that an unfeeling zombie would do equally well. I think he succeeds in being clear about this, though it’s a bit of a challenge because phenomenal consciousness is typically discussed in the context of perception, while rational decision-making tends to be seen in the context of the ‘easy problem’ – zombies can make the same decisions as us and even give the same rationales. When we talk about phenomenal consciousness being relevant to our decisions, I take it we mean something like our being able to sincerely claim that we ‘thought about’ a given decision in the sense that we had actual experience of relevant thoughts passing through our minds. A zombie twin would make identical claims but the claims would, unknown to the zombie, be false, a rather disturbing idea.

I won’t consider all of Clark’s arguments (which I am generally in sympathy with), but there are a few nice ones which I found thought-provoking. On epiphenomenalism, Clark has a neat manoeuvre. A commonly used example of an epiphenomenon, first proposed by Huxley, is the whistle on a steam locomotive; the boiler, the pistons, and the wheels all play a part in the causal story which culminates in the engine moving down the track; the whistle is there too, but not part of that story. Now discussion has sometimes been handicapped by the existence of two different conceptions of epiphenomenalism; a rigorous one in which there really must be no causal effects at all, and a looser one in which there may be some causal effects but only ones that are irrelevant, subliminal, or otherwise ignorable. I tend towards the rigorous conception myself, and have consequently argued in the past that the whistle on a steam engine is not really a good example. Blowing the whistle lets steam out of the boiler which does have real effects. Typically they may be small, but in principle a long enough blast can stop a train altogether.

But Clark reverses that unexpectedly. He argues that in order to be considered an epiphenomenon an entity has to be the sort of thing that might have had a causal role in the process. So the whistle is a good example; but because consciousness is outside the third-person account of things altogether, it isn’t even a candidate to be an epiphenomenon! Although that inverts my own outlook, I think it’s a pretty neat piece of footwork. If I wanted a come-back I think I would let Clark have his version of epiphenomenalism and define a new kind, x-epiphenomenalism, which doesn’t require an entity to be the kind of thing that could have a causal role; I’d then argue that consciousness being x-epiphenomenal is just as worrying as the old problem. No doubt Clark in turn might come back and argue that all kinds of unworrying things were going to turn out to be x-epiphenomenal on that basis, and so on; however, since I don’t have any great desire to defend epiphenomenalism I won’t even start down that road.

On the second worry Clark gives a sensible response to the issues raised by the research of Libet and others which suggest our decisions are determined internally before they ever enter our consciousness; but I was especially struck by his arguments on the potential influence of unconscious factors which form an important part of his wider case. There is a vast weight of scientific evidence to show that often enough our choices are influenced or even determined by unconscious factors we’re not aware of; Clark gives a few examples but there are many more. Perhaps consciousness is not the chief executive of our minds after all, just the PR department?

Clark nibbles the bullet a bit here, accepting that unconscious influence does happen, but arguing that when we are aware of say, ethnic bias or other factors, we can consciously fight against it and second-guess our unworthier unconscious impulses. I like the idea that it’s when we battle our own primitive inclinations that we become most truly ourselves; but the issues get pretty complicated.

As a side issue, Clark’s examples all suppose that more or less wicked unconscious biases are to be defeated by a more ethical conscious conception of ourself (rather reminiscent of those cartoon disputes between an angel on the character’s right shoulder and a devil on the left); but it ain’t necessarily so. What if my conscious mind rules out on principled but sectarian grounds a marriage to someone I sincerely love with my unconscious inclinations? I’m not clear that the sectarian is to be considered the representative of virtue (or of my essential personal agency) more than the lover.

That’s not the point at all, of course: Clark is not arguing that consciousness is always right, only that it has a genuine role. However, the position is never going to be clear. Suppose I am inclined to vote against candidate N, who has a big nose. I tell myself I should vote for him because it’s the schnozz that is putting me off. Oh no, I tell myself, it’s his policies I don’t like, not his nose at all. Ah, but you would think that, I tell myself, you’re bound to be unaware of the bias, so you need to aim off a bit. How much do \I aim off, though – am I to vote for all big-nosed candidates regardless? Surely I might also have legitimate grounds for disliking them? And does that ‘aiming off’ really give my consciousness a proper role or merely defer to some external set of rules?

Worse yet, as I leave the polling station it suddenly occurs to me that the truth is, the nose had nothing to do with it; I really voted for N because I’m biased in favour of white middle-aged males; my unconscious fabricated the stuff about the nose to give me a plausible cover story while achieving its own ends. Or did it? Because the influences I’m fighting are unconscious, how will I ever know what they really are, and if I don’t know, doesn’t the claimed role of consciousness become merely a matter of faith? It could always turn out that if I really knew what was going on, I’d see my consciousness was having its strings pulled all the time. Consciousness can present a rationale which it claims was effective, but it could do that to begin with; it never knew the rationale was really a mask for unconscious machinations.

The last of the three worries tackled by Clark is not strictly a philosophical or scientific one; we might well say that if people’s folk-dualist ideas are threatened, so much the worse for them. There is, however, some evidence that undiluted materialism does induce what Clark calls a “puppet” outlook in which people’s sense of moral responsibility is weakened and their behaviour worsened. Clark provides rational answers but his views tend to put him in the position of conceding that something has indeed been lost. Consciousness does and doesn’t matter. I don’t think anything worth having can be lost by getting closer to the truth and I don’t think a properly materialist outlook is necessarily morally corrosive – even in a small degree. I think what we’re really lacking for the moment is a sufficiently inspiring, cogent, and understood naturalised ethics to go with our naturalised view of the mind. There’s much to be done on that, but it’s far from hopeless (as I expect Clark might agree).

There’s much more in the paper than I have touched on here; I recommend a look at it.

Upon Thy Glimmering Thresholds

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.