I did initially wonder whether Ken Campbell, English theatre's resident zany, would be the best guide for such an expedition. Granted, his head makes a good drawing surface, so that an anaesthetist was able to sketch a map of the brain directly onto his bald dome, but the eccentric contents of that pink sketch-pad - its pleasure in surreal invention - seemed likely to obscure rather than clarify this challenging material.
Some viewers might also be startled by Campbell's diction: "I wanted to know who this Searle geezer was who gave Marvin such a short circuit," he said, referring to two distinguished opponents in the debate about artificial intelligence (AI). Occasionally, he just snorts, his face crumpling with bemusement. "Pfwarr!" he exclaimed at one point, after a peculiarly testing concept had been explained to him. But it would be a mistake to see Brainspotting as a work of crude popularisation. It actually turns out to be a work of sophisticated popularisation, relishing the possibilities of a field in which elaborate metaphor is a legitimate experimental tool (sometimes, indeed, the only legitimate one).
So when, in last week's programme, Campbell morosely summarised one theory about consciousness as being "like some Ronald Reagan presidency" ("Things are being done and decided and I'm only told about it afterwards"), the joke wasn't just a distracting flippancy. What's more, the argumentative gimmicks are presented with a nice wit. Returning from a conversation with Marvin Minsky, chief guru of strong AI (a camp that believes consciousness can be constructed), Campbell bounced into the room to announce that he had seen the light, only to find his doppelganger still gloomily convinced that John Searle is right. The doubling offered a kind of reassurance to confused viewers but the fact that the Minsky/Campbell was wearing a photographer's jerkin, just like his new hero, added a nice joke about the imitative behaviour charismatic thinkers inspire in their fans.
Last night's programme concentrated on that central disagreement - between those who believe that consciousness is essentially computational (and will eventually be replicated by a good enough computer), and those who argue that programmed intelligence, however convincing an imitation of sentience it gives, will never explain the mystery of consciousness. The best thing about Brainspotting was that it allowed you to choose where on this see-saw you wanted to sit, or, indeed, whether to climb on at all. I find myself somewhere on Minsky's side of the fulcrum, if not quite as far out - partly because the resistance to his arguments seems to display an essential vanity, an indignation that our privileged status in the world of matter might be threatened. (It is intriguing, incidentally, that those opposed to strong AI are so keen on building remodelled versions of the Cartesian theatre to prove their point, little rooms inhabited by imaginary observers or operators. It's as if the idea that consciousness might be a team effort, a neuronal ant's test rather than a room of one's own, is literally unthinkable for them.) But, because Brainspotting was offering good questions rather than good answers, there's no sense of being able to rest back on a comfortable fact. Whatever the mind is, this series makes it work.