Tag Archives: evolution

Symptoms of consciousness

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Where did consciousness come from? A recent piece in New Scientist (paywalled, I’m afraid) reviewed a number of ideas about the evolutionary origin and biological nature of consciousness. The article obligingly offered a set of ten criteria for judging whether an organism is conscious or not…

  • Recognises itself in a mirror
  • Has insight into the minds of others
  • Displays regret having made a bad decision
  • Heart races in stressful situations
  • Has many dopamine receptors in its brain to sense reward
  • Highly flexible in making decisions
  • Has ability to focus attention (subjective experience)
  • Needs to sleep
  • Sensitive to anaesthetics
  • Displays unlimited associative learning

This is clearly a bit of a mixed bag. One or two of these have a clear theoretical base; they could be used as the basis of a plausible definition of consciousness. Having insight into the minds of others (‘theory of mind’) is one, and unlimited associative learning looks like another. But robots and aliens need not have dopamine receptors or racing hearts, yet we surely wouldn’t rule out their being conscious on that account. The list is less like notes towards a definition and more of a collection of symptoms.

They’re drawn from some quite different sources, too. The idea that self-awareness and awareness of the minds of others has something to do with consciousness is widely accepted and the piece alludes to some examples in animals. A chimp shown a mirror will touch a spot that had been covertly placed on its forehead, which is (debatably) said to prove it knows that the reflection is itself. A scrub jay will re-hide food if it was seen doing the hiding the first time – unless it was seen only by its own mate. A rat that pressed the wrong lever in an experiment will, it seems, gaze regretfully at the right one (‘What do you do for a living?’ ‘Oh, I assess the level of regret in a rat’s gaze.’) Self-awareness certainly could constitute consciousness if higher-order theories are right, but to me it looks more like a product of consciousness and hence a symptom, albeit a pretty good one.

Another possibility is hedonic variation, here championed by Jesse Prinz and Bjørn Grinde. Many animals exhibit a raised heart rate and dopamine levels when stimulated – but not amphibians or fish (who seem to be getting a bad press on the consciousness front lately). There’s a definite theoretical insight underlying this one. The idea is that assigning pleasure to some outcomes and letting that drive behaviour instead of just running off fixed patterns instinctively, allows an extra degree of flexibility which on the whole has a positive survival value. Grinde apparently thinks there are downsides too and on that account it’s unlikely that consciousness evolved more than once. The basic idea here seems to make a lot of sense, but the dopamine stuff apparently requires us to think that lizards are conscious while newts are not. That seems a fine distinction, though I have to admit that I don’t have enough experience of newts to make the judgement (or of lizards either if I’m being completely honest).

Bruno van Swinderen has a different view, relating consciousness to subjective experience. That, of course, is notoriously unmeasurable according to many, but luckily van Swinderen thinks it correlates with selective attention, or indeed is much the same thing. Why on earth he thinks that remains obscure, but he measures selective attention with some exquisitely designed equipment plugged into the brains of fruit flies. (‘Oh, you do rat regret? I measure how attentively flies are watching things.’)

Sleep might be a handy indicator, as van Swinderen believes it is creatures that do selective attention that need it. They also, from insects to vertebrates (fish are in this time), need comparable doses of anaesthetic to knock them out, whereas nematode worms need far more to stop them in their tracks. I don’t know whether this is enough. I think if I were shown a nematode that had finally been drugged up enough to make it keep still, I might be prepared to say it was unconscious; and if something can become unconscious, it must previously have been conscious.

Some think by contrast that we need a narrower view; Michael Graziano reckons you need a mental model, and while fish are still in, he would exclude the insects and crustaceans van Swinderen grants consciousness to. Eva Jablonka thinks you need unlimited associative learning, and she would let the insects and crustaceans back in, but hesitates over those worms. The idea behind associative learning is again that consciousness takes you away from stereotyped behaviour and allows more complex and flexible responses – in this case because you can, for example, associate complex sets of stimuli and treat them as one new stimulus, quite an appealing idea.

Really it seems to me that all these interesting efforts are going after somewhat different conceptions of consciousness. I think it was Ned Block who called it a ‘mongrel’ concept; there’s little doubt that we use it in very varied ways, to describe the property of a worm that’s still moving at one end, to the ability to hold explicit views about the beliefs of other conscious entities at the other. We don’t need one theory of consciousness, we need a dozen.

Greatest Hits

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Give up on real comprehension, says Daniel Dennett in From Bacteria to Bach and Back: commendably honest but a little discouraging to the reader? I imagine it set out like the warning above the gates of Hell: ‘Give up on comprehension, you who turn these pages’.  You might have to settle for acquiring some competences.

What have we got here? In this book, Dennett is revisiting themes he developed earlier in his career, retelling the grand story of the evolution of minds. We should not expect big new ideas or major changes of heart ( but see last week’s post for one important one). It would have been good at this stage to have a distillation; a perfect, slim little volume presenting a final crystalline formulation of what Dennett is all about. This isn’t that. It’s more like a sprawling Greatest Hits album. In there somewhere are the old favourites that will always have the fans stomping and shouting (there’s some huffing and puffing from Dennett about how we should watch out because he’s coming for our deepest intuitions with scary tools that may make us flinch, but honestly by now this stuff is about as shocking and countercultural as your dad’s Heavy Metal collection); but we’ve also got unnecessary cover versions of ideas by other people, some stuff that was never really a hit in the first place, and unfortunately one or two bum notes here and there.

And, oh dear, another attempt to smear Descartes by association. First Dennett energetically promoted the phrase “Cartesian theatre” – so hard some people suppose that it actually comes from Descartes; now we have ‘Cartesian gravity’, more or less a boo-word for any vaguely dualistic tendency Dennett doesn’t like. This is surely not good intellectual manners; it wouldn’t be quite so bad if it wasn’t for the fact that Descartes actually had a theory of gravity, so that the phrase already has a meaning. Should a responsible professor be spreading new-minted misapprehensions like this? Any meme will do?

There’s a lot about evolution here that rather left me cold (but then I really, really don’t need it explained again, thanks); I don’t think Dennett’s particular gift is for popularising other people’s ideas and his take seems a bit dated. I suspect that most intelligent readers of the book will already know most of this stuff and maybe more, since they will probably have kept up with epigenetics and the various proposals for extension of the modern synthesis that have emerged in the current century, (and the fascinating story of viral intervention in human DNA, surely a natural for anyone who likes the analogy of the selfish gene?) none of which gets any recognition here (I suppose in fairness this is not intended to be full of new stuff). Instead we hear again the tired and in my opinion profoundly unconvincing story about how leaping (‘stotting’) gazelles are employing a convoluted strategy of wasting valuable energy as a lion-directed display of fitness. It’s just an evasive manoeuvre, get over it.

For me it’s the most Dennettian bits of the book that are the best, unsurprisingly. The central theme that competence precedes, and may replace, comprehension is actually well developed. Dennett claims that evolution and computation both provide ‘inversions’ in which intentionless performance can give the appearance of intentional behaviour. He has been accused of equivocating over the reality of intentionality, consciousness and other concepts, but I like his attitude over this and his defence of the reality of ‘free-floating rationales’ seems good to me. It gives us permission to discuss the ‘purposes’ of things without presupposing an intelligent designer whose purposes they are, and I’m completely with Dennett when he argues that this is both necessary and acceptable. I’ve suggested elsewhere that talking about ‘the point’ of things, and in a related sense, what they point to, is a handy way of doing this. The problem for Dennett, if there is one, is that it’s not enough for competence to replace comprehension often; he needs it to happen every time by some means.

Dennett sets out a theoretical space with ‘bottom-up vs top-down’, ‘random vs directed search’, and ‘comprehension’ as its axes; at one corner of the resulting cube we have intentionless structures like a termite colony; at the other we have fully intentional design like Gaudi’s church of the Sagrada Familia, which to Dennett’s eye resembles a termite colony. Gaudi’s perhaps not the ideal choice here, given his enthusiasm for natural forms; it makes Dennett seem curiously impressed by the underwhelming fact that buildings by an architect who borrowed forms from the natural world turn out to have forms resembling those found in nature.

Still, the space suggests a real contrast between the mindless processes of evolution and deliberate design, which at first sight looks refreshingly different and unDennetian. It’s not, of course; Dennett is happy to embrace that difference so long as we recognise that the ‘deliberate design’ is simply a separate evolutionary process powered by memes rather than genes.

I’ve never thought that memes, Richard Dawkins’s proposed cultural analogue of genes, were a particularly helpful addition to Dennett’s theoretical framework, but here he mounts an extended defence of them. One of the worst flaws in the theory as it stands – and there are several – is its confused ontology. What are memes – physical items of culture or abstract ideas? Dennett, as a professional philosopher, seems more sensitive to this problem than some of the more metaphysically naive proponents of the meme. He provides a relatively coherent vision by invoking the idea that memes are ‘tokens’; they may take all sorts of physical forms – written words, pictures, patterns of neuronal firing – but each form is a token of a particular way of behaving. The problem here is that anything at all can serve as a token of any meme; we only know that a given noise or symbol tokens a specific meme because of its meaning. There may be – there certainly are – some selective effects that bite on the actual form of particular tokens. A word that is long or difficult to pronounce is more likely to be forgotten. But the really interesting selections take place at the level of meanings; that requires a much more complex level of explanation. There may still be mechanisms involved that are broadly selective if not exactly Darwinian – I think there are – but I believe any move up to this proper level of complexity inevitably edges the simplistic concept of the meme out of play.

The original Dawkinsian observation that the development of cultural items sometimes resembles evolution was sound, but it implicitly called for the development of a general theory which in spite of some respectable attempts, has simply failed to appear. Instead, the supporters of memetics, perhaps trapped by the insistent drumbeat of the Dawkinsian circus, have tended to insist instead that it’s all Darwinian natural selection. How a genetic theory can be Darwinian when Darwin never heard of genes is just one of the lesser mysteries here (should we call it ‘Mendelian’ instead? But Darwin’s name is the hooray word here just as Descartes’ is the cue for boos). Among the many ways in which cultural selection does not resemble biological evolution, Dennett notes the cogent objection that there is nothing that corresponds to DNA; no general encoding of culture on which selection can operate. One of the worst “bum notes” in the book is Dennett’s strange suggestion that HTML might come to be our cultural DNA. This is, shall we say, an egregious misconception of the scope of text mark-up language.

Anyway, it’s consciousness we’re interested in (check out Tom Clark’s thoughtful take here) and the intentional stance is the number the fans have been waiting for; cunningly kept till last by Dennett. When we get there, though, we get a remix instead of the classic track. Here he has a new metaphor, cunningly calculated to appeal to the youth of today; it’s all about apps. Our impression of consciousness is a user illusion created by our gift for language; it’s like the icons that activate the stuff on your phone. You may object that a user illusion already requires a user, but hang on. Your ability to talk about yourself is initially useful for other people, telling them useful stuff about your internal states and competences, but once the system is operating, you can read it too. It seems plausible to me that something like that is indeed an important part of the process of consciousness, though in this version I felt I had rather lost track of what was illusory about it.

Dennett moves on to a new attack on qualia. This time he offers an explanation of why people think they occur – it’s because of the way we project our impressions back out into the world, where they may seem unaccountable. He demonstrates the redundancy of the idea by helpfully sketching out how we could run up a theory of qualia and noting how pointless they are. I was nodding along with this. He suggests that qualia and our own sense of being the intelligent designers in our own heads are the same kind of delusion, simply applied externally or internally. I suppose that’s where the illusion is.

He goes on to defend a sort of compatibilist view of free will and responsibility; another example of what Descartes might be tempted to label Dennettian Equivocation, but as before, I like that posture and I’m with him all the way. He continues with a dismissal of mysterianism, leaning rather more than I think is necessary on the interesting concept of joint understanding, where no one person gets it all perfectly, but nothing remains to be explained, and takes a relatively sceptical view of the practical prospects for artificial general intelligence, even given recent advances in machine learning. Does Google Translate display understanding (in some appropriate sense); no, or rather, not yet. This is not Dennett as we remember him; he speaks disparagingly of the cheerleaders for AI and says that “some of us” always discounted the hype. Hmm. Daniel Dennett, long-time AI sceptic?

What’s the verdict then? Some good stuff in here, but as always true fans will favour the classic album; if you want Dennett at his best the aficionado will still tell you to buy Consciousness Explained.

 

 

Evolving the Dark Tetrad.

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MachiavelliWhy are we evil? This short piece  asks how the “Dark Tetrad” of behaviours could have evolved.

The Dark Tetrad is an extended version of the Dark Triad of three negative personality traits/behaviours (test yourself here  – I scored ‘infrequently vile’). The original three are ‘Machiavellianism’ – selfishly deceptive, manipulative behaviour; Psychopathy – indifference or failure to perceive the feelings of others; and Narcissism – vain self-obsession. Clearly there’s some overlap and it may not seem clear that these are anything but minor variants on selfishness, but research does suggest that they are distinct. Machiavellians, for example do not over-rate themselves and don’t need to be admired; narcissists aren’t necessarily liars or deceivers; psychopaths are manipulative but don’t really get people.

These three traits account for a good deal of bad behaviour, but it has been suggested that they don’t explain everything; we also need a fourth kind of behaviour, and the leading candidate is ‘Everyday Sadism‘ ; simple pleasure in the suffering of others, regardless of whether it brings any other advantage for oneself. Whether this is ultimately the correct analysis of ‘evil’ behaviour or not, all four types are readily observable in varying degrees. Socially they are all negative, so how could they have evolved?

There doesn’t seem to me to be much mystery about why ‘Machiavellian’ behaviour would evolve (I should acknowledge at this point that using Machiavelli as a synonym for manipulativeness actually understates the subtlety and complexity of his philosophy). Deceiving others in one’s own interests has obvious advantages which are only negated if one is caught. Most of us practice some mild cunning now and then, and the same sort of behaviour is observable in animals, notably our cousins the chimps.

Psychopathy is a little more surprising. Understanding other people, often referred to as ‘theory of mind’ is a key human achievement, though it seems to be shared by some other animals to a degree. However, psychopaths are not left puzzled by their fellow human beings; it’s more that they lack empathy and see others as simply machines whose buttons can freely be pushed. This can be a successful attitude and we are told that somewhat psychopathic traits are commonly found in the successful leaders of large organisations. That raises the question of why we aren’t all psychopaths; my guess is that psycopathic behaviour pays off best in a society where most people are normal; if the proportion grows above a certain small level, the damage done by competition between psychopaths starts to outweigh the benefits and the numbers adjust.

Narcissism is puzzling because narcissists are less self-sufficient than the rest of us and also have deluded ideas about what they can accomplish; neither of these are positive traits in evolutionary terms. One positive side is that narcissists expect a lot from themselves and in the right circumstances they will work hard and behave well in order to protect their own self-image. It may be that in the right context these tendencies win esteem and occasional conspicuous success, and that this offsets the disadvantages.

Finally, sadism. It’s hard to see what benefits accrue to anyone from simply causing pain, detached from any material advantage. Sadism clearly requires theory of mind – if you didn’t realise other people were suffering, there would be no point in hurting them. It’s difficult to know whether there are genuine animal examples. Cats seem to torture mice they have caught, letting them go and instantly catching them again, but to me the behaviour seems automatic or curious, not motivated by any idea that the mice experience pain. Similarly in other cases it generally seems possible to find an alternative motivation.

What evolutionary advantage could sadism confer? Perhaps it makes you more frightening to rivals – but it may also make and motivate enemies. I think in this case we must assume that rather than being a trait with some downsides but some compensating value it is a negative feature that just comes along unavoidably with a large free-running brain. The benefit of consciousness is that it takes us out of the matrix of instinctive and inherited patterns of behaviour and allows detached thought and completely novel responses. In a way Nature took a gamble with consciousness, like a good manager recognising that the good staff might do better if left without specific instructions. On the whole, the bet has paid off handsomely, but it means that the chance of strange and unfavourable behaviour in some cases or on some occasions just has to be accepted. I the case of everyday sadism, the sophisticated theory of mind which human beings have is put to distorted and unhelpful use.

Maybe then, sadism is the most uniquely human kind of evil?

Now That’s What I Call Dennett

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dennettProfessors are too polite. So Daniel Dennett reckons. When leading philosophers or other academics meet, they feel it would be rude to explain their theories thoroughly to each other, from the basics up. That would look as if you thought your eminent colleague hadn’t grasped some of the elementary points. So instead they leap in and argue on the basis of an assumed shared understanding that isn’t necessarily there. The result is that they talk past each other and spend time on profitless misunderstandings.

Dennett has a cunning trick to sort this out. He invites the professors to explain their ideas to a selected group of favoured undergraduates (‘Ew; he sounds like Horace Slughorn’ said my daughter); talking to undergraduates they are careful to keep it clear and simple and include an exposition of any basic concepts they use. Listening in, the other professors understand what their colleagues really mean, perhaps for the first time, and light dawns at last.

It seems a good trick to me (and for the undergraduates, yes, by ‘good’ I mean both clever and beneficial); in his new book Intuition Pumps and Other Tools for Thinking Dennett seems covertly to be playing another. The book offers itself as a manual or mental tool-kit offering tricks and techniques for thinking about problems, giving examples of how to use them. In the examples, Dennett runs through a wide selection of his own ideas, and the cunning old fox clearly hopes that in buying his tools, the reader will also take up his theories. (Perhaps this accessible popular presentation will even work for some of those recalcitrant profs, with whom Dennett has evidently grown rather tired of arguing…. heh, heh!)

So there’s a hidden agenda, but in addition the ‘intuition pumps’ are not always as advertised. Many of them actually deserve a more flattering description because they address the reason, not the intuition. Dennett is clear enough that some of the techniques he presents are rather more than persuasive rhetoric, but at least one reviewer was confused enough to think that Reduction ad Absurdum was being presented as an intuition pump – which is rather a slight on a rigorous logical argument: a bit like saying Genghis Khan was among the more influential figures in Mongol society.

It seems to me, moreover, that most of the tricks on offer are not really techniques for thinking, but methods of presentation or argumentation. I find it hard to imagine someone trying to solve a problem by diligently devising thought-experiments and working through the permutations; that’s a method you use when you think you know the answer and want to find ways to convince others.

What we get in practice is a pretty comprehensive collection of snippets; a sort of Dennettian Greatest Hits. Some of the big arguments in philosophy of mind are dropped as being too convoluted and fruitless to waste more time on, but we get the memorable bits of many of Dennett’s best thought-experiments and rebuttals.  Not all of these arguments benefit from being taken out of the context of a more systematic case, and here and there – it’s inevitable I suppose – we find the remix or late cover version is less successful than the original. I thought this was especially so in the case of the Giant Robot; to preserve yourself in a future emergency you build a wandering robot to carry you around in suspended animation for a few centuries. The robot needs to survive in an unpredictable world, so you end up having to endow it with all the characteristics of a successful animal; and you are in a sense playing the part of the Selfish Gene. Such a machine would be able to deal with meanings and intentionality just the way you do, wouldn’t it? Well, in this brief version I don’t really see why or, perhaps more important, how.

Dennett does a bit better with arguments against intrinsic intentionality, though I don’t think his arguments succeed in establishing that there is no difference between original and derived intentionality. If Dennett is right, meaning would be built up in our brains through the interaction of gradually more meaningful layers of homunculi; OK (maybe), but that’s still quite different to what happens with derived intentionality, where things get to mean something because of an agreed convention or an existing full-fledged intention.

Dennett, as he acknowledges, is not always good at following the maxims he sets out. An early chapter is given over to the rules set out by Anatol Rapoport, most notably:

You should attempt to re-express your target’s position so clearly, vividly and fairly that your target says, “Thanks, I wish I’d thought of putting it that way.”

As someone on Metafilter said, when Dan Dennett does that for Christianity, I’ll enjoy reading it; but there was one place in the current book where I thought Dennett fell short on understanding the opposition. He suggests that Kasparov’s way of thinking about chess is probably the same as Deep Blue’s in the end. What on earth could provoke one to say that they were obviously different, he protests. Wishful thinking? Fear? Well, no need to suppose so: we know that the hardware (brain versus computer) is completely different and runs a different kind of process; we know the capacities of computer and brain are different and, in spite of an argument from Dennett to the contrary, we know the heuristics are significantly different. We know that decisions in Kasparov’s case involve consciousness, while Deep Blue lacks it entirely. So, maybe the processes are the same in the end, but there are some pretty good prima facie reasons to say they look very different.

One section of the book naturally talks about evolution, and there’s good stuff, but it’s still a twentieth century, Dawkinsian vision Dennett is trading in. Can it be that Dennett of all people is not keeping up with the science? There’s no sign here of the epigenetic revolution; we’re still in a world where it’s all about discrete stretches of DNA. That DNA, moreover, got to be the way it is through random mutation; no news has come in of the great struggle with the viruses which we now know has left its wreckage all across the human genome, and more amazing,  has contributed some vital functional stretches without which we wouldn’t be what we are. It’s a pity because that seems like a story that should appeal to Dennett, with his pandemonic leanings.

Still, there’s a lot to like; I found myself enjoying the book more and more as it went on and the pretence of being a thinking manual dropped away a bit.  Naturally some of Dennett’s old attacks on qualia are here, and for me they still get the feet tapping. I liked Mr Clapgras, either a new argument or more likely one I missed first time round; he suffers a terrible event in which all his emotional and empathic responses to colour are inverted without his actual perception of colour changing at all. Have his qualia been inverted – or are they yet another layer of experience? There’s really no way of telling and for Dennett the question is hardly worth asking. When we got to Dennett’s reasonable defence of compatibilism over free will, I was on my feet and cheering.

I don’t think this book supersedes Consciousness Explained if you want to understand Dennett’s views on consciousness. You may come away from reading it with your thinking powers enhanced, but it will be because your mental muscles have been stretched and used, not really because you’ve got a handy new set of tools. But if you’re a Dennett fan or just like a thoughtful and provoking read, it’s worth a look.

Bats without evolution – pt 1

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NagelThomas Nagel is one of the panjandrums of consciousness, author of the classic paper ‘What Is It Like To Be A Bat’ and so a champion of qualia; but also an important figure in inspiring the Mysterian school of pessimism.

Now he has inspired new controversy with his book ‘Mind and Cosmos: Why The Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False.’ Probably the part of the book which has elicited the most negative reaction is the doubts Nagel expresses about evolution itself, or rather about the currently accepted view of it. It’s not that Nagel disbelieves in evolution per se, but he thinks there are important gaps in its account; in particular he doesn’t think it accounts satisfactorily for the origin of life, or for the availability of the large range of living forms on which natural selection has worked. He is not endorsing Intelligent Design but he thinks some of its proponents have arguments which deserve a wider and more sympathetic readership.

That does seem a bit alarming. It’s true, I think, that we don’t yet have a full and convincing story of how life came out of inert chemistry. I’d also agree that some of the theories put forward in the past – like the naked replicators championed by Richard Dawkins in the Selfish Gene – look a bit sketchy and optimistic. But none of that would stop me putting my money on the true story being a fully materialist one in which Darwinian evolution plays an early and crucial role. Nagel’s second problem, with the way nature seems to have provided a remarkable fund of variation in organisms, of a kind which lent itself to the emergence of sophisticated organisms, just seems misconceived. He offers no statistical analysis or other reasoning as to why the standard account is unlikely, just mere incredulity. It seems amazing that that could have happened; well yes, it does, but then it also seems amazing that we’re sitting on a huge oblate spheroid which is rotating and orbiting round an even vaster sphere of terrifying thermonuclear activity; but there it is.

The real problem is that Nagel wants these doubts (together with some more specific objections to standard materialism) to justify a large metaphysical change in our conception of the whole cosmos. His book professes only to offer tentative and inadequately imaginative speculations, and the discussion is largely at a meta-theoretical level – he isn’t telling us what he thinks is the case, he’s discussing the kinds of theory that could in principle be advocated – but it’s clear enough what kind of theory he would prefer to reductive materialism. What he leans towards is a teleological theory; one in which some underlying principle drives the world towards a particular goal. He does not want this to be an intentional goal; he does not want God in the picture or any other Designer; rather he wants there to be a natural push towards value; value being conceived as a sort of goodness or moral utility, although this part of the speculative potential theory clearly needs development.

Nagel’s critique of evolution may seem alarmingly misplaced, but the idea of introducing teleology to fill the gaps seems really astonishing. What, we’re going to abandon the idea that DNA came together through natural selection and say instead that it came together because it sort of wanted to or was sort of meant to? The history of science has been a history of driving out teleological explanations – and the reason that represents progress is that teleological explanations are just not very good; they are usually vacuous and provide no real insight or predictive power.

In some ways what Nagel is after seems like an inverted law of entropy. Instead of things running down and tending to disorder, he wants there to be something built into the cosmos that shoves things towards elaboration, complexity, and indeed self-awareness (he positions the evolution of human consciousness as a peak of the process, and likens it to the Universe waking up). In itself that vision is quite appealling, but Nagel wants it to be driven by the worst kind of teleology.

I’m not sure what the official ontological status of the law of entropy is – it could be a meta-law which says the laws of nature must be such that entropy always increases, or it could be something that emerges from those laws (perhaps from any viable set of laws) – but it is definitely fully compatible with the rest of physics. If Nagel’s new teleology worked like this, it might be viable, but he actually supposes it is going to have to discreetly intervene at some point and turn events in a direction other than the one mere physics would have dictated. This seems a disastrous requirement. If there’s one thing the whole weight of science goes to prove, it’s that the laws of physics are not intermittent or interruptable; every experiment ever conducted has contributed evidence that they are consistent and complete. Yes, there are some places in quantum physics or wherever where some might hope to smuggle in a bit of jiggery-pokery, but I think on examination even these recondite areas offer no real hope of a loophole.

This is a general issue with Nagel’s case. We can sympathise with the view that evolution is not a Theory of Everything, but the other theories we need should be compatible with the broadly materialist world view which, despite some problems, is really the only fully-worked out one we’ve got: but Nagel hankers after something stranger and thinner.

What about those other theories? Nagel isn’t basing his argument simply on his doubts about evolution; he has three places in which he thinks the standard materialist view is just not adequate. Consciousness, unsurprisingly, is one; cognitive thought, more unexpectedly, is another; and the third is his concept of value. In the next post let’s consider what he has to say about each.