Friday, November 12, 2010

Peter Hacker tells James Garvey that neuroscientists are talking nonsense

This was posted at The Philosopher's Magazine recently - I suspect that Hacker's perspective is more common than one might guess in looking at all the research being done in the realm of neuroscience.

Hacker’s challenge

Peter Hacker tells James Garvey that neuroscientists are talking nonsense

Peter Hacker

Peter Hacker

So long as people read Wittgenstein, people will read Peter Hacker. It’s hard to imagine how his work on the monumental Analytical Commentary on Wittgenstein’s Philosophical Investigations could possibly be superseded. He spent nearly twenty years on that project (ten of them in cooperation with his friend and colleague Gordon Baker), following in Wittgenstein’s footsteps, and producing a large number of important articles and books on topics in the philosophy of mind and language along the way. Nearer the end than the beginning of a distinguished career as an Oxford don, at a time of life when most academics would be happy to leave the lectern behind and collapse somewhere with a nice glass of wine, Hacker is in the middle of another huge project, this time on human nature. He also seems keen to pick a fight with almost anyone doing the philosophy of mind.

This has a much to do with his view of philosophy as a contribution to human understanding, not knowledge. One might think that philosophy has the same general aim as science – securing knowledge of ourselves and the world we live in – even if its subject matter is more abstract and its methods more armchair. What is philosophy if not an attempt to secure new knowledge about the mind or events or beauty or right conduct or what have you? According to Hacker, philosophy is not a cognitive discipline. It’s something else entirely.

“Philosophy does not contribute to our knowledge of the world we live in after the manner of any of the natural sciences. You can ask any scientist to show you the achievements of science over the past millennium, and they have much to show: libraries full of well-established facts and well-confirmed theories. If you ask a philosopher to produce a handbook of well-established and unchallengeable philosophical truths, there’s nothing to show. I think that is because philosophy is not a quest for knowledge about the world, but rather a quest for understanding the conceptual scheme in terms of which we conceive of the knowledge we achieve about the world. One of the rewards of doing philosophy is a clearer understanding of the way we think about ourselves and about the world we live in, not fresh facts about reality.”

His account of the nature of philosophy is Wittgensteinian through and through. It’s a conception of philosophy which regards philosophical problems as confusions in language rather than deep mysteries encountered in the world. The job of the philosopher is to make these conceptual errors clear to us and in so doing help us out of our muddles. Philosophical questions aren’t solved; they’re dissolved. There is knowledge here, in a sense, but it’s not the sort of knowledge most philosophers think they are pursuing.

“By doing philosophy you come to realise things about the structure of our conceptual scheme that you would never have realised otherwise. Realization is indeed a dawning of knowledge. But the knowledge here is not knowledge of the world we live in. It is knowledge of the structure of our conceptual scheme. It very often looks like “metaphysical knowledge” of reality – as it were knowledge of the scaffolding of the world. But it’s no such thing. The world doesn’t have scaffolding. Rather, in doing philosophy, we come to realise the character of the grammatical and linguistic scaffolding from which we describe the world, not the scaffolding of the world.”

Because he thinks of philosophy is a quest for understanding, on Hacker’s view it can’t be transmitted from generation to generation as knowledge can. Each generation has to earn insight, has to face its own obstacles and work out an understanding for itself. This strikes a chord. I wonder about the present generation and what Hacker thinks might get in the way of our understanding.

“The main barrier is the scientism that pervades our mentality and our culture. We are prone to think that if there’s a serious problem, science will find the answer. If science cannot find the answer, then it cannot be a serious problem at all. That seems to me altogether wrong. It goes hand in hand with the thought that philosophy is in the same business as science, as either a handmaiden or as the vanguard of science. This prevailing scientism is manifest in the infatuation of the mass media with cognitive neuroscience. The associated misconceptions have started to filter down into the ordinary discourse of educated people. You just have to listen to the BBC to hear people nattering on about their brains and what their brains do or don’t do, what their brains make them do and tell them to do. I think this is pretty pernicious – anything but trivial.”

In the last decade Hacker has turned his attention from the philosophy of language to the philosophy of mind, dealing with what he sees as a whole raft of conceptual confusions in cognitive neuroscience. Philosophical Foundations of Neuroscience, which he co-authored with the neurophysiologist M. R. Bennett, works through a number of tangles in detail. As we talk about some of them, I begin to see that there is a straight line from his Wittgensteinian thoughts about the nature of philosophy to his work on the mind.

“It has often struck me as ironical that Wittgenstein is criticised for being a quietist. It is true that he said philosophy leaves everything as it is. This has wrongly been interpreted as meaning that according to Wittgenstein philosophy is impotent – that it is powerless to affect anything at all. This is a gross misinterpretation of what he wrote. It also seems to me the exact opposite of the truth. What Wittgenstein says should be left alone is the grammar of our language. It’s not our business to devise better grammars. Our business is to tidy up linguistic or conceptual confusions rooted, among other places, in existing grammar. What we can do is clarify and disentangle conceptual confusions in the sciences. Of course, that’s what I tried to do with Max Bennett in the neuroscience book. I wish more people were engaged in this kind of enterprise. There are far too many philosophers who take their task to be to sing the Hallelujah Chorus to the sciences. It seems to me we should be serious, and one hopes helpful, conceptual critics of the sciences.”

One of his larger criticisms of contemporary neuroscience concerns the way it characterises the activities of the brain. Dualists about the mind and brain – those who hold that there are thinking substances like souls in the world as well as all the ordinary physical stuff – say that the mind sees and thinks and wants and calculates. Contemporary neuroscience dismisses this as crude, but Hacker argues that it just ends up swapping the mind with the brain, saying that the brain sees and thinks and wants and calculates. He says, “Merely replacing Cartesian ethereal stuff with glutinous grey matter and leaving everything else the same will not solve any problems. On the current neuroscientist’s view, it’s the brain that thinks and reasons and calculates and believes and fears and hopes. In fact, it’s human beings who do all these things, not their brains and not their minds. I don’t think it makes any sense to talk about the brain engaging in psychological or mental operations.”

But don’t we talk this way, harmlessly, all the time? When we say that our computer wants to install an update, that it does not recognise the printer, we’ve adopted what Daniel Dennett calls “the intentional stance”. We explain and predict what the computer might do as though it were a rational agent with desires and intentions. We can skip the unnecessary details of hardware and software, quickly work out that we need to install a driver, and get on with our lives. In speaking like this no one thinks a computer really, literally wants to do anything. Maybe neuroscientists don’t actually think that some region of the brain really remembers or thinks or fears. It’s just a useful fiction. It enables us to get on with the work. Where’s the harm in that?

“If that were all it was, it would be perfectly harmless, but I don’t think that is all the neuroscientists and cognitive scientists who say this are asserting. The fact is that if you look from one domain of cognitive neuroscience to another you will find that the operations of the brain thus conceived are being advanced as explanations for human behaviour, for our thinking, believing, seeing, hoping and fearing. That’s wrong, because it’s no explanation. If someone wants to know why poor old Snodgrass, as the result of some lesion, can’t do something that normal people can do, and you say that his brain can’t do it, you haven’t advanced any explanation at all. One cannot explain why someone cannot see by saying that his brain cannot see. One cannot explain why someone behaves in a certain way by suggesting that his brain tells him to. Cognitive defects can indeed sometimes be explained by reference to damage to the brain – but not by reference to cognitive deficiencies of the brain, since the brain has no cognitive powers at all. There is no such thing as a brain’s thinking, wanting, reasoning, believing or hypothesizing.”

The thought that philosophers of mind and cognitive neuroscientists are talking sheer nonsense recurs several times in Hacker’s treatment of their conception of consciousness. I want to pin him down on the expression “what it’s like”, because he might be on to something. The phrase appeared in Thomas Nagel’s 1974 paper, “What is it Like to be a Bat?”, and the words are invoked almost everywhere in philosophy of mind, even by scientists with philosophical ambition. Nagel puts his point succinctly: “an organism has conscious mental states if and only if there is something that it is like to be that organism – something it is like for the organism”. When many philosophers and neuroscientists try to say what consciousness is or capture what it is about consciousness that gives them trouble, they talk about how experiences feel, about what it’s like for the subject. Hacker thinks it’s all a muddle. In fact, he says, there’s nothing it’s like to be you. As I line up a question by paraphrasing his reasons for saying this, I leave too much out, and he corrects my omission generously with an image owed to Wittgenstein.

“Those are some of the reasons. Any decent philosophical problem is held in place not by one mistake or confusion but by a whole range. Wittgenstein has a wonderful metaphor: if you shine strong light on one side of a problem, it casts long shadows on the other. Every deep philosophical confusion is held in place by numerous struts, and one cannot demolish the confusion merely by knocking one strut away. One has to circle around the problem again and again to illuminate all the misconceptions that hold it in place.” We consider several of the struts in question, including the ones I missed out.

“You can ask any human being having an experience ‘What was it like for you to have that experience?’ Most commonly the answer is: ‘Nothing in particular.’ What was it like to see the lamp post? What was it like to see your shoes?’ – ‘The experience was quite indifferent!’ Sometimes the answer would be, ‘It was wonderful, marvellous, joyful, jolly good or revolting, disgusting, awful’–and so on. If you want to generalise over that, engage as Nagel does in second-level quantification, the result is not ‘There is something which it is like to experience such and such’, but ‘There is something which it is to experience such and such, namely wonderful, awful, exciting, boring’. Why? Because the answer to ‘What was it like for you to do it?’ isn’t ‘It was like wonderful’ – unless we’re in California – but rather ‘It was wonderful’. So it is a plain confusion to think that for any given experience of a conscious creature, there is something that it is like for the creature to have that experience. Sometimes there is something that it is to experience this-or-that – most of the time there isn’t. That’s one pair of mistakes.”

“Another kind of mistake is a systematic confusion between the qualities of an experience and the qualities of the objects of an experience. The question ‘What was it like for you to love Daisey?’ can be given an answer by specifying the hedonic character of the experience of being in love with her. It may have been wonderful, or heart-breaking. The question ‘What is it like to see something red?’ has no such answer. Seeing a red button, for example, is neither wonderful nor heart-breaking, neither exciting nor boring – it simply lacks any hedonic quality. But philosophers in the so-called consciousness studies community are prone to try to characterise the experience by reference to the qualities of the objects of the experience – as if the ‘redness of red’ were a quality of the experience of seeing a red thing.” He growls: “The redness of the red! That’s not what it’s like for you to see red. That’s what you see! What’s it like to see red? For the most part, nothing at all. Maybe seeing that wonderful red sparkle of that fantastic flower was intoxicating. Well then, it was intoxicating to see it. What you saw was the colour. It was the experience that was intoxicating. People confuse the object of experience with the positive or negative hedonic quality of the experience.”

The final confusion he identifies concerns the suggestion that what is unique to conscious beings is that there is something that it is like for them to be the beings that they are. Philosophers say, for example, that there is not anything that it is like for an ink-jet printer to be an ink-jet printer, nothing it is like for a brick to be a brick. However, there does seem to be something it is like for a bat to be a bat. There is something it is like for us to be humans. There is something it is like for you to be you, and for me to be me. There seems to be a meaningful distinction here between conscious things and everything else. For perhaps most philosophers of mind, this “what it is like” is the core of the mystery of consciousness.

Hacker argues that this is a muddle. He says that questions about what it’s like to be a something require contrast classes. “You can ask what it is like for an X to be a Y, but not what it is like for an X to be an X. If the question takes the form ‘What is it like for a human being to be a human being? – that amounts to no more than ‘What is it like to be a human being?’ This question has lost the ‘for someone’. It means no more than “What is human life like?” – and that has a pretty easy, if rather vague, answer. What’s it like for a bat to be a bat? Since bats can’t be anything other than bats, all that means is ‘What is the life of a bat like?’ Any decent zoologist can no doubt tell you in considerable detail what bats do, what they enjoy, and what frightens them. That’s what the life of a bat is like. There’s nothing mysterious here.”

“It looks mysterious because it’s modelled on ‘what’s it like for an X to be a Y?’”. He goes into character for a moment: “Daddy, what was it like for you to be a soldier in The Second World War? All sorts of stories follow. Daddy, what’s it like for you to be a human being? What on Earth is this question? The question is illegitimate. It’s stepped over the bounds of sense. The requirement is that there be a difference between the X and the Y. What’s it like for a woman to be a surgeon? Perfectly decent question. What’s it like for a woman to be a woman?”

He’s warmed to his subject, but now he trails off, his hands open, and he quietly leans back in his chair. I think he has chosen to pass over this enormous part of contemporary philosophy of mind in silence. I do take the point. If “what it’s like for an X” expressions need contrasts in order to make sense, and Nagel has left that bit unspecified, then Nagel’s version is nonsense. As a result we have an expression that looks sensible, but when we try to use it or answer questions based on it, we find that we can’t. The thought is that there is something it’s like for a bat to be a bat, but I can’t say what it is. There’s a bit of the world which has to exist – there must be something it’s like for a bat to be a bat – but I can’t describe it. Worse, I can’t describe it even if I have all the physical facts about a bat at my disposal. Is there something non-physical I don’t know? Is dualism true? The mystery closes in from every side.

Go read the whole article.


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