1996/09/12 @ British Association Science Fair

Fame, at last!

'The good idea that I now use I owe to a great philosopher... Andy Warhol: "In the future, everybody will be famous for 15 minutes".'

'Only a philosopher would have the chutzpah to write a book called Consciousness Explained, said Prof Daniel Dennett, who is, does and has.

As the set-piece conclusion of Thursday's BA session on Brains, Minds and Consciousness, Prof Dennett gave the BA a run-through of the ideas in that book -- updated and (despite almost total technical failure) clarified.

In the book, he sets out to demolish the idea of the 'Cartesian Theatre' -- an idea named for the philosopher Descartes, who described (in effect) the 'mind' as viewing the world on a screen processed by the brain. Descartes, notoriously, regarded the 'I', as in 'I think, therefore I am', as quite separate from the physical brain.

Dennett's new idea is to label the alternative, which he had previously decribed in abstract terms. For an idea, feeling or perception to reach consciousness is equivalent, he now says, to it becoming famous. To be famous for 15 minutes is impossible -- fame is not at all the same as appearing on some (inner) TV, but depends on reputation, on being remembered.

He opened by telling the story of the professional magician who flummoxed colleagues -- but only colleagues -- with 'The Tuned Deck' trick. Each time they thought they'd worked out how the trick worked, he shuffled the deck of cards (pack, in British English), accepted whatever restriction they put on him (keeping his right hand behind his back, for example) and successfully repeated the trick.

'Like all great magic,' Dennett explained, 'it's over before the trick begins. The trick was in the name, and it wasn't the word "deck" and it wasn't "tuned": it was "the". The magician had convinced them that there was one big trick that they had to figure out... but he was just doing all the tricks they already knew... when they stopped him doing one, he'd do another.'

Consciousness, Dennett was saying, is not One Big Trick: and the temptation to believe it is is a major source of confusion.

'I just can't imagine how consciousness can be explained by the activity of the brain,' people say. And they conclude 'So mind must be a mystery.'

'I don't have a quarrel with the premise,' Dennett replies. 'But I draw a different conclusion: "Try harder".'

As Dennett's sees it, consciousness is distributed throughout the entire brain. Ideas and understandings arise through different processes competing, with the 'winner' becoming the focus of our attention for the moment. Indeed, all attempts to find a single place in the brain where attention is have failed.

He gave the example of a subtle visual illusion. Take a green ring. Draw a blue dot that fits exactly into the centre of the ring. Flash them alternately on a screen at different rates. At some rate of flashing, the blue dot will disappear from view.

Is there a set of processes which the images go through before they cross some Rubicon and 'reach consciousness'? In that case, does 'the ring ambush the dot before it gets into the charmed circle?' This Dennett calls the Stalinist Show-trial option: reality is edited before it is recorded. Or does 'the dot does make it into the fabled land of consciousness -- and then the ring comes along and erases it?' That's the Orwellian alternative, in which history is re-written.

Dennett's answer is: neither. There is no charmed circle. Processing and memory are one set of competing processes. What happens in the illusion is that the blue dot nearly becomes famous in your mind, but a miss is as good as a mile, and it's the green ring which actually achieves fame.