Commuting days until retirement: 451
Commuting at this time of year, with the lengthening mornings and evenings, gives me a chance to lose myself in the sight of tracts of England sliding across my field of vision – I think of Philip Larkin in The Whitsun Weddings: ‘An Odeon went past, a cooling tower, and someone running up to bowl…’ (His lines tend to jump into my mind like this). It’s tempting to enlarge a scene like this into a simile for life, like the one that Larkin’s poem leads into. Of course we are not just passive observers, but the notion of life as a film show – a series of scenes progressing past your eyes – has a certain curious attractiveness.
Now imagine that, as I sit in the train, I am not quite a human being as you think of one. Instead I’m a cleverly constructed robot who appears in every way like a human but, being a robot, has something important missing. The objects outside the train form images on some sensor in each of my pseudo-eyes, and the results may then be processed by successive layers of digital circuitry which perform ever more sophisticated interpretative functions. Perhaps these resolve the light patterns that entered my ‘eyes’ into discrete objects, and and trigger motor functions which cause my head and eyes to swivel and follow them as they pass. Much, in fact, like the real me, idly watching the scenes sliding by.
Now let’s elaborate our robot to have capabilities beyond sitting on a train and following the objects outside; now it can produce all the behaviour that any human being can.This curious offspring of a thought-experiment is what philosophers refer to as a zombie – not the sort in horror films with the disintegrating face and staring eyeballs, but a creature who may be as well behaved and courteous as any decent human being. The only difference is that, despite (we presume) the brain churning away as busily as anyone else’s, there are no actual sensations in there – none of those primary, immediate experiences with a subjective quality: the fresh green of a spring day, or the inner rapture of an orgasm. So what’s different? There are a number of possibilities, but, as you will have guessed, the one I am thinking of is that inner, subjective world of experience we all have, but assume that machines do not. This is well expressed by saying that there’s something that it is like to be me, but not something that it’s like to be a machine.(1) The behaviour is there all right, but that’s all. In the phrase I rather like, the lights are on but nobody’s at home.
Many people who think about the question nowadays, especially those of a scientific bent, tend to conclude that, of course, we must ultimately be nothing but machines of one sort or another. We have discovered many – perhaps most – of the physical principles upon which our brains and bodies work, and we have traced their evolution over time from simple molecular entities. So there we are – machines. But conscious machines – machines that there is something it is like to be? It has frequently been debated whether or not such a machine with all these capabilities would ipso facto be conscious – whether it would have a mind. Or, in other words, whether we could in principle build a conscious machine. (There are some who speculate that we may already have done so.)
One philosophical response to this problem is that of behaviourism, a now justly neglected philosophical position.(2) If you are a behaviourist you believe that your mind, and your mental activity – your thoughts – are defined in terms of your behaviour. The well-known Turing Test constitutes a behaviourist criterion, since it is based on the principle that a computer system whose responses are indistinguishable from those of a human is taken for all practical purposes to have a mind. (I wrote about Turing a little while ago – but here I part company with him.) And for a behaviourist, the phrase ‘What it is like to be…’ can have no meaning, or at best a rather convoluted one based on what we say or do; but its meaning is plain and obvious to you or me. It’s difficult to resist repeating the old joke about behaviourism: two post-coital behaviourists lie in bed together, and one says ‘That was great for you – how was it for me?’ But I take the view of behaviourism that the joke implies – it’s absurd.
Behaviourists, however, can’t be put down as burglars or voyeurs: they don’t peer into the lighted windows to see what’s going on inside. It’s enough for them that the lights are on. For them the concept of a zombie is either meaningless or a logical impossibility. But there is another position on the nature of the mind which is much more popular in contemporary thought, but which has a different sort of problem with the notion of a zombie. I’m thinking of eliminative materialism.
Well, as I write this post, I feel it extending indefinitely as more ideas churn through that machine I refer to as my brain. So to avoid it becoming impossibly long, and taking another three weeks to write it, I’ll stop there, and just entitle this piece as Part 1. Part 2 will take up the topic of eliminative materialism.
In the meantime I’d just like to leave one thought: I started with a snatch of Philip Larkin, and I’ve always felt that poetry is in essence a celebration of conscious experience; without consciousness I don’t believe that poetry would be possible.
(1) The phrase is mainly associated with Thomas Nagel, and his influential 1974 paper What is it Like to be a Bat? But he in turn attributes it to the English philosopher Timothy Sprigge.
(2) I’m referring to the philosophical doctrine of behaviourism – distinct from, but related to the psychological one – J B Watson, B F Skinner et al.