Daniel C.Dennett

SWEET DREAMS

Philosophical obstacles to a science of consciousness

This is a book about the "hard question", as David Chalmers has memorably called it. According to Chalmers and those who think like him, none of the research and theorising about how the brain works sheds any light on what it feels like to be a conscious individual. Explaining the existence of this feeling is the hard question.

Dennet's position is that there is no hard question. This is the thesis he defends in his short book, which is really one of the numerous postscripts he has written to his earlier full-length treatment of the subject in Consciousness Explained (1991).

On the view that Dennett is critcising, our experience comes to us through the senses and constitutes what philosophers call qualia; the seeing of something red, like a tomato, is often cited as an example. A lot of philosophical debate has gone on about the possibility, or otherwise, that there could exist so-called zombies. A philosophical zombie would be a creature exactly like us in all respects but without any interior life, without qualia.

Dennett is prominent among those who reject the conceivability of zombies, and indeed his first chapter has the title "The Zombic Hunch". The hunch in question is the widespread (and, Dennett concedes, intuitively appealing) conviction that a description of the processes in the brain, no matter how complete, would always leave something out. But Dennett insists that nothing is left out. Difficult although it is to accept this fact, fact it is.

The remaining chapters take the discussion further along the same lines and are, in places, rather more technical. However, Dennett is an exceptionally clear writer and there are plenty of humorous asides and light touches, so non-professional readers are not excluded. Among the topics discussed are the third person approach to consciousness, the validity of qualia, and the right way to interpret a well-known thought experiment about "Mary", a brain scientist who has spent all her life in a monochromatic world (could she know about colour in advance of experiencing it?). Dennet's position is that this thought experiment is misleading—an example of what he calls an intuition pump.

Dennett is always a stimulating writer. Is he persuasive? In some moods I find that he is. I certainly experience the force of the zombic hunch and intuitively I feel that consciousness is special. But I also begin to suspect that Dennett is right to say that this is an illusion, on a par with the illusion that the sun goes round the earth or that there is a life essence additional to the physics and chemistry going on inside our cells. And perhaps, as he says, with time the illusion will pass though whether that will be wholly beneficial is perhaps a different question.

6 March 2007