Blunder around for a while
- Consciousness Explained by Daniel Dennett
Little, Brown, 514 pp, $27.95, October 1991, ISBN 0 316 18065 3
For more than forty years, starting with the publication of Ryle’s very influential The Concept of Mind in 1949, some of the best of the analytic philosophers have devoted themselves to the question of whether we can find a satisfactory substitute for what Ryle sneeringly called ‘the ghost in the machine’ – Descartes’s picture of human beings as divided into a material body and an immaterial mind. Philosophy of mind is one of the few clear instances of intellectual progress which analytic philosophy has to its credit. If one reads the contributions of post-Rylean anti-Cartesians in chronological order – Wilfrid Sellars, J.J.C. Smart, David Armstrong, Hilary Putnam, Jerry Fodor, Donald Davidson, Ruth Millikan, Patricia and Paul Churchland – one gets a clear sense of a developing consensus. There is increasing agreement about which moves will and won’t work, which strategies are dead and which still alive. Bad questions have been gradually set aside and better ones posed. Discussion has become steadily more sophisticated.
Until now, however, no book in this area has matched the freshness, originality and power of Ryle’s. The Concept of Mind was a brilliant attempt to undo what Descartes had done and substitute a view of human beings more like Aristotle’s. Aristotle, Ryle thought, had sensibly seen that to talk about someone’s mind is to talk about features of her intellect and character, not to talk about something incorporeal mysteriously lodged within her. Ryle wrote with wit and bravura, in prose which was accessible to non-philosophers. His book toppled settled philosophical convictions like ninepins, and was rightly taken as the showpiece of post-war British philosophy.
Daniel Dennett, who was one of Ryle’s students, has spent the last twenty-five years writing about the topic – consciousness – which has always been the great obstacle to the acceptance of Ryle’s non-Cartesian account of mind. Most of this work, however, has been in the form of articles, each of them incisive and Vigorous, yet hard to fit together into a coherent doctrine. Now, however, he has brought off a remarkable feat: he has written a book with all the boldness, originality and panache of The Concept of Mind.
Consciousness Explained is a triumph of perspicuous organisation, as well as a fine piece of philosophical writing. If one were asked which contemporary philosopher crafts the best English prose, Dennett would be one of the first to come to mind. Like The Concept of Mind, this book can be read with genuine pleasure by a non-philosopher; anyone who picks it up will be swept up in the excitement of Dennett’s project. Even a reader who has never looked into a psychology book, or taken an interest in computers, will find herself absorbed in summaries of complicated psychological and physiological experiments, and in brief but clear accounts of curious computer programs. Dennett integrates all these into the development of his ‘Multiple Drafts’ model of consciousness with great skill, and moves smoothly back and forth between laboratory results and philosophical generalisations. Whereas The Concept of Mind was essentially the product of one man’s armchair reflections, Consciousness Explained is the upshot of active co-operation, of two decades’ worth of conferring, arguing and consensus-building by cognitive scientists – by the psychologists, linguists and philosophers who have been thinking about the resemblances and differences between computers and people.
The greatest difference between the two books, however, is methodological. Ryle thought that ‘conceptual analysis’ (the sort of thing which, in Ryle’s day, analytic philosophers were supposed to be skilled at – detecting the ‘real’ meaning, or the ‘real’ grammar, of linguistic expressions) sufficed to dethrone Descartes. Dennett realises that nothing will do that job except a brand-new description of ourselves, one whose use will gradually dissipate our tendency to build Cartesian presuppositions into our questions about the mind. The difference between Ryle and Dennett is the difference between saying that, since Descartes bamboozled us, we should get back to good old common sense (and to Aristotle, who embodied it), and saying something less bluff and more nuanced: that Descartes did a reasonably good job, a job which needed to be done. He developed a non-Aristotelian description of humans which harmonised with the corpuscularian, anti-Aristotelian tenor of 17th-century science. It was a description which worked well for some purposes. But it also produced a lot of philosophical headaches, and a lot of weird theories. We can avoid these headaches and that weirdness if we can come up with a new way of talking about our distinctively human abilities, one which will improve on both Aristotle’s and Descartes’s.
The heart of Dennett’s book is his attempt to persuade us that we can safely give up questions which presuppose what he calls ‘the Cartesian Theatre’ – presuppose that ‘I’ names a sort of observer of the events which are ‘present to consciousness’. As Dennett says, ‘the idea of a special centre in the brain’ – the relic of Descartes’s suggestion that mind and body interface at the pineal gland – ‘is the most tenacious idea bedevilling our attempts to think about consciousness.’ It seems as natural to contemporary psychologists as it did to Descartes to suggest that, ‘however difficult it might be to determine in practice the precise location of the Continental Divide in the brain’, still there must be ‘a highest point, a turning-point’, a place in between the afferent and the efferent nerves where a quasi-person sits. This quasi-person is the real, incorporeal you – the you that might, conceivably, survive even after the brain rots.
When Hume pointed out that no such quasi-person, no referent for the term ‘I’, was introspectible, Kant rejoined that the fact that ‘the “I think” can accompany all my representations’ showed that there was a ‘transcendental ego’ for which neither empirical psychology nor physiology could possibly account. German idealism, the great bulwark which the 19th century erected against scientific naturalism, owed its existence to Kant’s success in thus rehabilitating the ghost Descartes had postulated. The conviction which idealists shared with Husserlian phenomenologists – that consciousness must for ever remain opaque to natural science – has been the basis of an enormous amount of bad philosophy from Kant’s day to this. Many people have claimed that human dignity would somehow be compromised if psycho-physiology should ever succeed in de-transcendentalising the ego – if we should ever be revealed to be ‘mere machines’. Many others have claimed that we must drastically revise our self-image now that we have realised that we are just Turing machines made out of protoplasm.
[*] MIT, 226 pp., $9.95, April, 0 262 03148 5.
Vol. 13 No. 24 · 19 December 1991
So Richard Rorty has joined Daniel Dennett (LRB, 21 November) on the connectionism-will-solve-all-our-philosophical-problems bandwagon. But like the similar enthusiasm for AI (Artificial Intelligence), this fervour is more a fashion created by what people think connectionism promises than a detailed understanding of what it can and cannot do. In the beginning AI promised much: but over time it has become apparent, as Rorty correctly observes, that it can only deliver what its programmers have already programmed into it. Rorty and Dennett enthuse over connectionism because it appears to be free of this problem. They are wrong. Connectionism suffers a similar, but undiscussed difficulty known as the training problem.
Essentially, connectionism concerns networks made up of interconnected units (and hidden units), each with adjustable ‘thresholds’ which learn generalisations by being trained upon exemplars and error correction. In somewhat simplified terms, networks learn by being given inputs which the network converts into outputs. Following the network’s output, the thresholds between its units are changed depending upon whether the output was correct or not. The training problem concerns where the network gets the information needed for this error-correction process. The problem is that error correction makes the training of a network dependent upon some kind of external assistance to tell it whether its output was the correct response to the input it was given: without this knowledge it cannot tell whether it has made an error or not and so cannot be trained. So while networks do not need programmers they do need some kind of external help.
Rorty and Dennett focus upon the wonderful generalisations networks can learn. They ignore where the external help needed to train networks might come from. But for many cognitive skills there is no easy way networks in the brain can obtain the error-correction feedback needed to train them. The problem is recursive: if there was a process in the brain which could provide this information then its own development would depend in turn upon some further process. For some cognitive processes like reading there may be ways out. Connectionist accounts of reading successfully account for human reading performance. It is likely that the error correction needed to train them comes in part from a separate kind of process which sounds out written words from their spelling (hence the difficulty in learning to read encountered by children with problems over sounding out words). However, there is no reason to assume consciousness is going to have such an easy way out of the training problem (and certainly Dennett has not provided one). It may be that even with connectionist models we will still find a need for God. Consciousness may have to remain unexplained for a bit longer.
If ‘what distinguishes a conscious state from a non-conscious state’ is, as Dennett claims, the former’s having ‘a higher-order accompanying thought that is about the state in question’, then what should we call the supposedly ‘non-conscious’ states experienced by animals aware of the presence of food, say, to distinguish those states from the non-conscious states that rocks and machinery and the like apparently experience throughout their existence? More important, what do we call that which experiences either a conscious or a non-conscious state of awareness if not a ‘consciousness’? And how can a Cartesian be wrong in supposing this ‘experiencing mechanism’ to be significantly different from its contents?
On a more mundane plane, I’d also like to know why Rorty disruptively goes against established usage concerning the generic third-person pronoun. Is it only to signal her sympathy for the neurotically hyper-offendable, or does she have some intelligent reason for it?
Port Charlotte, Florida
Vol. 14 No. 1 · 9 January 1992
It’s a while since I’ve come across an example of that fine old genre, the Glowing Review that is also a narrative of mastery. But it’s made a major comeback in Richard Rorty’s piece on Dennett’s Consciousness Explained (LRB, 21 November 1991). Who better than Rorty to stage it, with its all-star dramatis personae: Aristotle, Descartes, Hegel, Hume, Kant, Orwell, Stalin, Ryle – with Roger Penrose, John Searle and Thomas Nagel appropriately designated walk-on roles. And it’s stirring stuff. Dennett, student of a great master who ‘toppled settled philosophical convictions like ninepins’ in a work that ‘was rightly taken as the show-piece of post-war British philosophy’, has pulled off a remarkable feat. He has produced a work to equal it in boldness, originality and panache, full of ‘seminal’ arguments, which also display ‘an idiosyncratic mastery of metaphor’ etc, etc.
Well, this is all fine and for those who like that sort of thing it is most definitely the sort of thing they like. I don’t mind a good Helden-sage myself if I’m in the mood, as a matter of fact but that’s strictly provided they leave me – that is ‘she’ – out of it. I do object to being inscribed in the text when the roles for women are so lousy. What do I get here? ‘Aristotle, Ryle thought, had sensibly seen that to talk about someone’s mind is to talk about the features of her intellect and character …’ Penrose & Co agree that there are right answers to the question ‘ “What is immediately given to consciousness?”, where “given” is construed in such a way that the subject herself may be quite wrong about what is given to her consciousness’. ‘Even a reader who has never looked into a psychology book, or taken an interest in computers, will find herself absorbed in summaries of complicated psychological and physiological experiments, and in brief but clear accounts of curious computer programs.’ ‘Anyone sufficiently intrigued by this book to want a better understanding of this model will get what she wants from Andy Clark’s clear, helpful …’
After Aristotle has given my mind the once over and some of his distant descendants have surmised that I am wrong in the head, I get to be a B-stream reader who is to be offered brief, clear and helpful explanations about what goes on in the realms of seminal thought. Gee, thanks.
Bolton Point, New South Wales
Richard Rorty is obviously of the opinion that Daniel Dennett has shouted ‘fire’ in a crowded Cartesian Theatre. If so, many will be expected to make a beeline to the nearest available exit. But on reflection (whatever that may be), Dennett is not convinced there is a Cartesian Theatre – no theatre, no exit – perhaps no fire either. In any event, I suspect John Searle and Thomas Nagel, regardless of where they are now seated, will indeed be hanging around for the second feature.
Red Bank, New Jersey
Vol. 14 No. 4 · 27 February 1992
Richard Rorty’s review of Dennett’s Consciousness Explained was lucid and helpful (LRB, 21 November 1991). I wish to refer those interested in its themes to Edward Hundert’s Philosophy, Psychiatry and Neuroscience, where similar ideas are developed.
Harvard Medical School