Both this and the following statement are false. Douglas Hofstadter and Daniel Dennett’s book is well worth £9.95.
One does not have to be a philosopher to realise that I have already gone further than a humble book-reviewer should. The value of the book under review is, you might think, a matter of opinion. Not so. It has now been established as a logically necessary truth.
Consider the first statement in the paragraph above: ‘Both this and the following statement are false.’ If this statement were true, it would by its own claim be false. Therefore it cannot be true, and the only logical alternative is that it is in fact false. Consider the second statement: ‘Hofstadter and Dennett’s book is well worth £9.95.’ If this statement were also false, then both statements would be false – which is precisely what the first statement claims. But that would mean that the first statement was true after all, which we have just established that it cannot be. Therefore the second statement cannot be false, and the only logical alternative is that it is true.
People who like this kind of thing will undoubtedly find this book the kind of thing they like. Counting myself among them, I would reckon The Mind’s I cheap at twice the price.
The Mind’s I – The Mind is I, The I of the Mind? – is a set of essays, fairy stories and brain-teasers by 19 different authors, chosen by Hofstadter and Dennett because they illuminate in one way or another the problems of self-reference, personal identity, consciousness, and the relations between language, mind and brain. The editors have, as they put it, ‘arranged and composed’ the pieces, and they have provided for each an engaging ‘reflection’ or commentary. Although the book is philosophical in the best sense of the term, there is little in it by way of straight philosophy; and although it touches on issues central to psychology, neurophysiology and the computer sciences, it assumes no technical or factual expertise.
‘In poetry,’ Auden wrote in The Dyer’s Hand, ‘all facts and all beliefs cease to be true or false and become interesting possibilities.’ The Mind’s I itself comes close to poetry. It is a book of fantasies and thought-experiments, an exploration of possible worlds, possible people, possible machines and possible divinities. True or false – or, as in several cases, neither one thing nor the other – these possibilities are designed to make us consider and reconsider a host of concepts which we take for granted.
Once upon some future time, imagine your brain is physically separated from the rest of your body, but with all the usual connections to muscles and sense-organs preserved by radio links. If your brain is, say, in a bath of warm saline in a hospital in Paris, while your body is walking the streets of London, where will you be? If your body then commits a felony, who or what should go to prison? Imagine a machine which can make a perfect copy of any existing physical structure, atom for atom. Suppose it makes a copy of you. What will you say to this copy when the two of you are introduced (and what will the copy say to you)? Suppose, having taken all your vital statistics in 1982, the machine does not produce the finished copy until 1992. What will you say to yourself in ten years’ time, when you meet yourself as you were ten years ago? Imagine the nerve cells in your head are one by one replaced by microchips, which function exactly like the original nerve cells. At what point, if any, in this process of replacement will your stream of consciousness be interrupted? Suppose that instead of being put into your head, the replacement chips are kept in a laboratory from which connections into the system are made by remote control. Suppose, indeed, they are kept in lots of different laboratories. What will it feel like when your replacement brain has thus been spread around the world? Imagine you say to God, ‘God, I am afraid of sinning, and I know I shall regret it,’ and He says: ‘That’s all right then, I won’t stop you sinning, but I’ll take away your feelings of regret.’ How will you respond to this well-meaning offer? Imagine you wake up one morning and find yourself still in the middle of a dream ...
These and other still more worrying paradoxes are explored here in the form of literary fables, serious if playful academic papers, and reviews (in the case of Stanislaw Lem’s ‘Non Serviam’, a review of a non-existent book). Some of the pieces, such as Borges’s ‘Borges and I’ and Turing’s ‘Computing Machinery and Intelligence’, are classics. Others have been previously published but are less well-known. And others appear to have been specially written for this book. Dennett has included among other things Hofstadter’s ‘Prelude ... Ant Fugue’ taken from the latter’s Gödel, Escher, Bach, and Hofstadter has included Dennett’s ‘Where am I?’ taken from the latter’s Brainstorms. Besides their joint and several contributions to the commentaries and introduction, the editors have also provided a helpful guide to further reading, (Alas, this guide is not quite as helpful as it seems. A paper, cited as Lenneberg 1975, turns out to be no more than a summary by someone else of an unpublished experiment, which adds nothing to the summary already given in this book. Eric Lenneberg committed suicide in 1975. Perhaps Hofstadter, who at one point in The Mind’s I conducts a conversation with Einstein’s brain after Einstein’s death, knows something which the rest of us do not.)
You might think that any philosopher who valued his academic reputation would have been shy of putting his name to a collection which is so unashamedly exotic and bizarre. Indeed, in Brainstorms, published only three years ago, Dennett’s strange story about losing his brain (or was it his body?) was left to the last chapter, where it was described somewhat coyly as a ‘dessert’. But here such a disclaimer would be out of place. For the whole book is a book of desserts, without any attempt to provide a well-balanced or more wholesome diet. Nanny, of course, will tell you that such rich fare cannot be good for you: too much of the Tao, not enough of the oaTs.
I can’t help feeling that Nanny might be right. This is a rich book, and a dangerously unbalanced one. Paradoxes are fun; they can be illuminating. But we should be wary of the temptation to celebrate paradoxes as a royal road to some higher level of reality – as if, with their help, we might expect to discover a conceptual world where contraries are all resolved, where ‘Is’ and ‘Is not’, ‘So’ and ‘Not so’ are smoothed away. Such Taoist doctrines may have proved productive in other fields of science – in atomic physics, for example, where irreconcilable notions about the nature of matter have apparently been resolved by the discovery of quantum field theory – but they are not what is most obviously needed in the science of mind.
Despite Hofstadter and Dennett’s view that what is needed is a revolutionary new theory of the relation between mind and matter, I am not persuaded that many of the paradoxes presented here represent mysteries which can only be resolved by an appeal to principles as yet unknown. As often as not, they seem to represent nothing more than good old-fashioned muddles, of the kind which human thinkers habitually get into when they carry over their familiar concepts into unfamiliar territory. At the risk of being accused of teaching philosophers to suck eggs, I would suggest that what is missing from this book is the recognition that our ideas and our language operate – and are meant to operate – only within the limits of the ‘game’ for which they are designed. Human perception, human thought and even human ways of doing philosophy have evolved as adaptations to the world of the experienced past, not of the yet-to-be-experienced future. It is the world of the past which constitutes what John Bowlby has called ‘the environment of adaptiveness’. And, as Alice discovered when she observed the croquet game in Wonderland, outside the environment of adaptiveness anything can happen.
Examples abound, not merely in fantasies and thought-experiments, but in well-tried fact. In normal circumstances, people have, for example, no trouble making an unambiguous decision about whether an object is coloured red or green. But let someone be induced by an experimental psychologist to look at a red object with one eye while he looks at a green object with the other, and he will – when conditions are right – confidently report that what he sees is a single object which is coloured ‘red and green all over’ (not part red part green, not red and green by turns, but red and green all over). In normal circumstances, people have no trouble making sensible three-dimensional interpretations of flat line drawings. But let someone be shown the drawing shown above, in which Escher has cunningly flouted the familiar rules of linear perspective, and what he will see is an ‘impossible’ staircase which goes on and on for ever. In normal circumstances, people have no trouble using the common-or-garden ideas of ‘truth’ and ‘falsity’ for the analysis of human discourse. But let someone be persuaded by a Cretan philosopher into making the (wholly unlikely) statement ‘I am lying,’ and he will find, whatever his mental state, that he has made a statement which he never meant to make.
They are fun, such paradoxes. But surely the last thing we need to do is to resolve them: to waste our philosophical energies on, say, inventing a new definition of colour, or a new kind of 4-d 3-d space, or even (pace Bertrand Russell) a new typology of ‘truth’.
And the same goes, I think, for most of the paradoxes of mind and matter which are at the centre of this book. What the book so cleverly demonstrates is that when people carry over their common-sense concepts about mind into the Wonderland of Science Fiction computers, teleclones and brain surgery, they can and do get those common-sense concepts in a twist. They find themselves concluding, for example, that a person can be both here and there at the same time, or that consciousness can reside in the pages of a book, or that a machine can have free will. But the question which is often implicit in the stories and the commentaries – namely, ‘Can we invent a new kind of philosophical elastic which will save us in future from the embarrassment of having our mental concepts dangling round our knees?’ – seems to me the wrong one. The question ought to be ‘Can we use this embarrassment to discover just what the limits on our existing concepts are and – why?’ In other words, a question of psychology, rather than philosophy. And a question of evolutionary psychology at that.
My own view is this. Most of our everyday mental concepts – the ideas of mind, person, consciousness, free will etc – are primitive concepts with which human beings are saddled not merely by cultural convention but by a long biological history. They are, if you like (and some will not), ‘innate ideas’: ideas which people inevitably grow up with and grow into, because the cognitive development of human beings has been shaped by natural selection to meet certain very special ends.
For millions of years the most significant and at the same time the most perplexing intellectual task that all human beings have had to face has been the task of doing what I have called ‘natural psychology’ – understanding and predicting the behaviour of the fellow human beings who form their social group. Psychology is a difficult thing to do. So difficult that the task of doing natural psychology would probably have proved impossible in the absence of some sort of conceptual guidelines (witness, by comparison, the failure in recent times of open-ended systems of academic psychology such as Behaviourism). But human beings in the course of evolution have in fact developed their own guidelines. And they have done so by a remarkable device: the invention of the faculty of reflexive consciousness. Reflexive consciousness, by giving each individual a picture of the ‘psychological structure’ which underlies his own behaviour, provides him with a framework for interpreting the behaviour of others like himself.
Thus most of our everyday mental concepts are, in this sense, natural psychological concepts – which we can no more do without or wish away than we can wish away our human concepts of colour, space or truth.
Dennett, in his writings elsewhere, sometimes seems close to adopting a similar perspective. In this book, however, considerations of the evolutionary function of human mental concepts receive no quarter. Dennett joins Hofstadter in Wonderland, where like a couple of Mad Hatters they invite us to take tea at a table miles away from the environment to which our concepts are adapted. And, teasing though their paradoxes are, the questions they raise – Can machines think? What would it feel like if my head was separated from my body? Whose side is God on? – are ultimately silly questions. About as silly as the late Archbishop’s question ‘Is AID adultery?’, or President Reagan’s ‘Can the US win a nuclear war?’ No, of course machines can’t think. The environment of adaptiveness of the term ‘think’ is the world of human intelligence, just as the environment of adaptiveness of the term ‘adultery’ is the world of human sexual intercourse, and the environment of adaptiveness of the term ‘winning a war’ is the world of conventional military strategy.
I don’t say that Hofstadter and Dennett’s questions will never be worth asking. One day their interesting possibilities might indeed become commonplace realities, and if that happens we shall have to re-adapt to this new world. But first things first. Both this and the following statement are false. Mental philosophy should not try to run before evolutionary psychology can walk.