Monthly Archives: October 2018

Boltzmann Brains

Posted on by
12

Solipsism, the belief that you are the only thing that really exists (everything else is dreamed or imagined by you), is generally regarded as obviously false; indeed, I’ve got it on a list somewhere here as one of the conclusions that tell you pretty clearly that your reasoning went wrong somewhere along the way; a sort of reductio ad absurdum. There don’t seem to be any solipsists, (except perhaps those who believe in the metempsychotic version) – but perhaps there are really plenty of them and they just don’t bother telling the rest of us about their belief, since in their eyes we don’t exist.

Still, there are some arguments for solipsism, especially its splendid parsimony. William of Occam advised us to use as few angels as possible in our cosmology, or more generally not to multiply entities unnecessarily. Solipsism reduces our ontological demand to a single entity, so if parsimony is important it leads the field. Or does it? Apart from oneself, the rest of the cosmos, according to solipsists, is merely smoke and mirrors; but smoke takes some arranging and mirrors don’t come cheap. In order for oneself to imagine all this complex universe, one’s own mind must be pretty packed with stuff, so the reduction in the external world is paid for by an increase in the internal one, and it becomes a tricky metaphysical question as to whether deeming the entire cosmos to be mental in nature actually reduces one’s ontological commitment or not.

Curiously enough, there is a relatively new argument for solipsism which runs broadly parallel to this discussion, derived from physics and particularly from the statistics of entropy. The second law of thermodynamics tells us that entropy increases over time; given that, it’s arguably kind of odd that we have a universe with non-maximal entropy in the first place. One possibility, put forward with several other ideas by Ludwig Boltzmann in 1896, is that the second law is merely a matter of probability. While entropy generally tends to increase, it may at times go the other way simply by chance.  Although our observed galaxy is highly improbable, therefore, if you wait long enough it can occur just by chance as a pocket of low entropy arising from chance fluctuations in a vastly larger and older universe (really old; it would have to be hugely older than we currently believe the cosmos to be) whose normal state is close to maximal entropy.

One problem with this is that while the occurrence of our galaxy by chance is possible, it’s much more likely that a single brain in the state required for it to be having one’s current experiences should arise from random fluctuations. In a Boltzmannic universe, there will be many, many more ‘Boltzmann brains’ like this than there will be complete galaxies like ours. Such brains cannot tell whether the universe they seem to perceive is real or merely a function of their random brain states; statistically, therefore, it is overwhelmingly likely that one is in fact a Boltzmann brain.

To me the relatively low probability demands of the Boltzmann brain, compared with those of a full universe, interestingly resemble the claimed low ontological requirement of the solipsism hypothesis, and there is another parallel. Both hypotheses are mainly used as leverage in reductio arguments; because this conclusion is absurd, something must be wrong with the assumptions or the reasoning that got us here. So if your proposed cosmology gives rise to the kind of universe where Boltzmann brains crop up ‘regularly’, that’s a large hit against your theory.

Usually these arguments, both in relation to solipsism and Boltzmann brains, simply rest on incredulity. It’s held to be just obvious that these things are false. And indeed it is obvious, but at a philosophical level, that won’t really do; the fact that something seems nuts is not enough, because nutty ideas have proven true in the past. For the formal logical application of reductio, we actually require the absurd conclusion to be self-contradictory; not just silly, but logically untenable.

Last year, Sean Carroll came up with an argument designed to beef up the case against Boltzmann brains in just the kind of way that seems to be required; he contends that theories that produce them cannot simultaneously be true and justifiably believed. Do we really need such ‘fancy’ arguments? Some apparently think not. If mere common sense is not enough, we can appeal to observation. A Boltzmann brain is a local, temporary thing, so we ought to be able to discover whether we are one simply by observing very distant phenomena or simply waiting for the current brain states to fall apart and dissolve. Indeed, the fact that we can remember a long and complex history is in itself evidence against our being Boltzmanns.

But appeals to empirical evidence cannot really do the job; there are several ways around them. First, we need not restrict ourselves literally to a naked brain; even if we surround it with enough structured world to keep the illusion going for a bit, our setup is still vastly more likely than a whole galaxy or universe. Second, time is no help because all our minds can really access is the current moment; our memories might easily be false and we might only be here for a moment. Third, most people would agree that we don’t necessarily need a biological brain to support consciousness; we could be some kind of conscious machine supplied with a kind of recording of our ‘experiences’. The requirement for such a machine could easily be less than for the disconnected biological brain.

So what is Carroll’s argument? He maintains that the idea of Boltzmann brains is cognitively unstable. If we really are such a brain, or some similar entity, we have no reason to think that the external world is anything like what we think it is. But all our ideas about entropy and the universe come from the very observations that those ideas now apparently undermine. We don’t quite have a contradiction, but we have an idea that removes the reasons we had for believing in it. We may not strictly be able to prove such ideas wrong, but it seems reasonable, methodologically at least, to avoid them.

One problem is those pesky arguments about solipsism. We may no longer be able to rely on the arguments about entropy in the cosmos, but can’t we borrow Occam’s Razor and point out that a cosmos that contains a single Boltzmann brain is ontologically far less demanding than a whole universe? Perhaps the Boltzmann arguments provide a neat physics counterpart for a philosophical case that ultimately rests on parsimony?

In the end, we can’t exactly prove solipsism false; but we can perhaps do something loosely akin to Carroll’s manoeuvre by asking: so what if it’s true? Can we ignore the apparent world? If we are indeed the only entity, what should we do about it, either practically or in terms of our beliefs? If solipsism is true, we cannot learn anything about the external world because it’s not there, just as in Carroll’s scenario we can’t learn about the actual world because all our perceptions and memories are systematically false. We might as well get on with investigating what we can investigate, or what seems to be true.

 

 

Just deserts

Posted on by
14

Dan Dennett and Gregg Caruso had a thoughtful debate about free will on Aeon recently. Dennett makes the compatibilist case in admirably pithy style. You need, he says, to distinguish between causality and control. I can control my behaviour even though it is ultimately part of a universal web of causality. My past may in the final sense determine who I am and what I do, but it does not control what I do; for that to be true my past would need things like feedback loops to monitor progress against its previously chosen goals, which is nonsensical. This concept of being in control, or not being in control, is quite sufficient to ground our normal ideas of responsibility for our actions, and freedom in choosing them.

Caruso, who began by saying he thought their views might turn out closer than they seemed, accepts pretty well all of this, agreeing that it is possible to come up with conceptions of responsibility that can be used to underpin talk of free will in acceptable terms. But he doesn’t want to do that; instead he wants to jettison the traditional outlook.

At this point Caruso’s motivation may seem puzzling. Here we have a way of looking at freedom and responsibility which provides a philosophically robust basis for our normal conception of those two moral basics – ideas we could not easily do without in our everyday lives. Now sometimes philosophy may lead us to correct or reject everyday ideas, but typically only when they appear to be without rational justification. Here we seem to have a logically coherent justification for some everyday moral concepts. Isn’t that a case of ‘job done’?

In fact, as he quickly makes clear, Caruso’s objections mainly arise from his views on punishment. He does not believe that compatibilist arguments can underpin ‘basic desert’ in the way that would be needed to justify retributive punishment. Retribution, as a justification for punishment, is essentially backward looking; it says, approximately, that because you did bad things, bad things must happen to you. Caruso completely rejects this outlook, and all justifications that focus on the past (after all, we can’t change the past, so how can it justify corrective action?). If I’ve understood correctly, he favours a radically new regime which would seek to manage future harms from crime in broadly the way we seek to manage the harms that arise from ill-health.

I think we can well understand the distaste for punishments which are really based on anger or revenge, which I suspect lies behind Caruso’s aversion to purely retributive penalties. However, do we need to reject the whole concept of responsibility to escape from retribution? It seems we might manage to construct arguments against retribution on a less radical basis – as indeed, Dennett seeks to do. No doubt it’s right that our justification for punishments should be forward looking in their aims, but that need not exclude the evidence of past behaviour. In fact, I don’t know quite how we should manage if we take no account of the past. I presume that under a purely forward-looking system we assess the future probability of my committing a crime; but if I emerge from the assessment with a clean bill of health, it seems to follow that I can then go and do whatever I like with impunity. As soon as my criminal acts are performed, they fall into the past, and can no longer be taken into account. If people know they will not be punished for past acts, doesn’t the (supposedly forward-looking) deterrent effect evaporate?

That must surely be wrong one way or another, but I don’t really see how a purely future-oriented system can avoid unpalatable features like the imposition of restrictions on people who haven’t actually done anything, or the categorisation of people into supposed groups of high or low risk. When we imagine such systems we imagine them being run justly and humanely by people like ourselves; but alas, people like us are not always and everywhere in charge, and the danger is that we might be handing philosophical credibility to people who would love the chance to manage human beings in the same way as they might manage animals.

Nothing, I’m sure, could be further from Gregg Caruso’s mind; he only wants to purge some of the less rational elements from our system of punishment. I find myself siding pretty much entirely with Dennett, but it’s a stimulating and enlightening dialogue.

Not Objectifiable

Posted on by
31

A bold draft paper from Tom Clark tackles the explanatory gap between experience and the world as described by physics. He says it’s all about the representational relation.

Clark’s approach is sensible in tone and intention. He rejects scepticism about the issue and accepts that there is a problem about the ‘what it is like’ of experience, while also seeking to avoid dualism or more radical metaphysical theories. He asserts that experience is not to be found anywhere in the material world, nor identified in any simple way with any physical item; it is therefore  outside the account given by physics. This should not worry us, though, any more than it worries us that numbers or abstract concepts cannot be located in space; experience is real, but it is a representational reality that exists only for the conscious subjects having it.

The case is set out clearly and has an undeniable appeal. The main underlying problem, I would say, is that it skates quite lightly past some really tough philosophical questions about what representation really is and how it works, and the ontological status of experience and representations. We’re left with the impression that these are solvable enough when we get round to them, though in fact a vast amount of unavailing philosophical labour has gone into these areas over the years. If you wanted to be unkind, you could say that Clark defers some important issues about consciousness to metaphysics the way earlier generations might have deferred them to theology. On the other hand, isn’t that exactly where they should be deferred to?

I don’t by any means suggest that these deferred problems, if that’s a fair way to describe them, make Clark’s position untenable – I find it quite congenial in general – but they possibly leave him with a couple of vulnerable spots. First, he doesn’t want to be a dualist, but he seems in danger of being backed into it. He says that experience is not to be located in the physical world – so where is it, if not in another world? We can resolutely deny that there is a second world, but there has to be in some sense some domain or mode in which experience exists or subsists; why can’t we call that a world? To me, if I’m honest, the topic of dualism versus monism is tired and less significant than we might think, but there is surely some ontological mystery here, and in a vigorous common room fight I reckon Clark would find himself being accused of Platonism (or perhaps congratulated for it) or something similar.

The second vulnerability is whether representation can really play the role Clark wants it to. His version of experience is outside physics, and so in itself it plays no part in the physical world. Yet representations of things in my mind certainly influence my physical behaviour, don’t they? The keyboard before me is represented in my mind and that representation affects where my fingers are going next. But it can’t be the pure experience that does that, because it is outside the physical world. We might get round this if we specify two kinds of representational content, but if we do that the hard causal kind of representation starts to look like the real one and it may become debatable in what sense we can still plausibly or illuminatingly say that experience itself is representational.

Clark makes some interesting remarks in this connection, suggesting there is a sort of ascent going on, whereby we start with folk-physical descriptions rooted in intersubjective consensus, quite close in some sense to the inaccessibly private experience, and then move by stages towards the scientific account by gradually adopting more objective terms. I’m not quite sure exactly how this works, but it seems an intriguing perspective that might provide a path towards some useful insight.

Are highs really high?

Posted on by
4

Are psychedelic states induced by drugs such as LSD or magic mushrooms really higher states of consciousness? What do they tell us about leading theories of consciousness? An ambitious paper by Tim Bayne and Olivia Carter sets out to give the answers.

You might well think there is an insuperable difficulty here just in defining what ‘high’ means. The human love of spatial metaphors means that height has been pressed into service several times in relevant ways. There’s being in high spirits (because cheerful people are sort of bouncy while miserable ones are droopy and lie down a lot?). To have one’s mind on higher things is to detach from the kind of concerns that directly relate to survival (because instead of looking for edible roots or the tracks of an edible animal, we’re looking up doing astronomy?). Higher things particularly include spiritual matters (because Heaven is literally up there?).  In philosophy of mind we also have higher order theories, which would make consciousness a matter of thoughts about thoughts, or something like that. Quite why meta-thoughts are higher than ordinary ones eludes me. I think of it as diagrammatic, a sort of table with one line for first order, another above for second, and so on. I can’t really say why the second order shouldn’t come after and hence below the first; perhaps it has to do with the same thinking that has larger values above smaller ones on a graph, though there we’re doubly metaphoric, because on a flat piece of paper the larger graph values are not literally higher, just further away from me (on a screen, now… but enough).

Bayne and Carter in passing suggest that ‘the state associated with mild sedation is intuitively lower than the state associated with ordinary waking awareness’. I have to say that I don’t share that intuition; sedation seems to me less engaged and less clear than wakefulness but not lower. The etymology of the word suggests that sedated people are slower, or if we push further, more likely to be sitting down – aha, so that’s it! But Bayne and Carter’s main argument, which I think is well supported by the evidence, is that no single dimension can capture the many ways in which conscious states can vary. They try to uphold a distinction between states and contents, which is broadly useful, though I’m not sure it’s completely watertight. It may be difficult to draw a clean distinction, for example, between a mind in a spiritual state and one which contains thoughts of spiritual things.

Bayne and Carter are not silly enough to get lost in the philosophical forest, however, and turn to the interesting and better defined question of whether people in psychedelic states can perceive or understand things that others cannot. They look at LSD and psilocybin and review two kinds of research, questionnaire based and actual performance test. This allows them to contrast what people thought drugs did for their abilities with what the drugs actually did.

So, for example, people in psychedelic states had a more vivid experience of colours and felt they were perceiving more, but were not actually able to discriminate better in practice. That doesn’t necessarily mean they were wrong, exactly; perhaps they could simply have been having a more detailed phenomenal experience without more objective content; better qualia without better data/output control. Could we, in fact, take the contrast between experience and performance as an unusually hard piece of evidence for the existence of qualia? The snag might be that subjects ought not to be able even to report the enhanced experience, but still it seems suggestive, especially about the meta-problem of why people may think qualia are real. To complicate the picture, it seems there is relatively good support for the idea that psychedelics may increase the rate of data uptake, as shown by such measures as rates of saccadic eye movements (the involuntary instant shifts that happen when your eyes snap to something interesting like a flash of light automatically).

Generally psychedelics would seem to impair cognitive function, though certain kinds of working memory are spared; in particular (unsurprisingly) they reduce the ability to concentrate or focus. People feel that their creative capacities are enhanced by psychedelics; however, while they do seem to improve the ability to come up with new ideas they also diminish the ability to tell the difference between good ideas and bad, which is also an important part of successful creativity.

One interesting area is that psychedelics facilitate an experience of unity, with time stopping or being replaced by a sense of eternity, while physical boundaries disappear and are overtaken by a sense of cosmic unity. Unfortunately there is no scientific test to establish whether these are perceptions of a deeper truth or vague delusions, though we know people attach significance and value to these experiences.

In a final section Bayne and Carter take their main conclusion – that consciousness is multidimensional – and draw some possibly controversial conclusions. First, they note that that the use of psychedelics has been advocated as a treatment for certain disorders of consciousness. They think their findings run contrary to this idea, because it cannot be taken for granted that the states induced by the drugs are higher in any simple sense. The conclusion is perhaps too sweeping; I should say instead that the therapeutic use of psychedelic drugs needs to be supported by a robust case which doesn’t rest on any simple sense of higher or lower states.

Bayne and Carter also think their conclusion suggests consciousness is too complex and variable for global workspace theories to be correct. These theories broadly say that consciousness provides a place where different sensory inputs and mental contents can interact to produce coherent direction, but simply being available or not available to influence cognition seems not to capture the polyvalence of consciousness, in Bayne and Carter’s view.

They also think that multidimensionality goes against the Integrated Information Theory (IIT). IIT gives a single value for level of consciousness, and so is evidently a single dimension theory. One way to achieve a reconciliation might be to accept multidimensionality and say that IIT defines only one of those dimensions, albeit an important one (“awareness”?). That might involve reducing IIT’s claims in a way its proponents would be unwilling to do, however.