In much the same spirit, Campbell has always resisted closure, preferring supposing to believing: "This whole thing about belief seems nuts... it's a kind of blinkering thing. But if you can suppose a thing, it just means `Can you put your mind around it, just for the moment?' And it would seem to be a mind-widening business."
His mind gets widened in the most literal sense in Brainspotting ("Not my title, incidentally"), a series of three television programmes in which Campbell explores the great questions of philosophy: what is consciousness? how did it evolve? is it possible to build a machine that has a mind? do human beings have a Self? Along the way, he has his brain hypothetically removed and put in a vat, for purposes of illustration, though quite what is being illustrated is never satisfactorily explained.
To those people - most of us, I would guess - who know Campbell only as Alf Garnett's neighbour in In Sickness and in Health, or as the devil taking a break from tormenting the damned in the Kit-Kat advert, this probably looks like something of a departure. To Campbell's followers - "seekers", he calls them, though what they are searching for (thrills? laughs? the Answer?) isn't clear - the continuity is easier to spot.
Since Furtive Nudist was premiered in 1988, Campbell has written and performed a series of shows giving vent to his probing, mistrustful picture of the universe. He explored hats, two-faced acting, Greek tragedy and South Pacific pidgin in Pigspurt. He looked at the secret military functions of the National Theatre, mind-manipulation machines and the "Duke of Edinburgh Cult" of the South Pacific island of Tanna in Jamais Vu. Together with Furtive Nudist, these were performed at the National Theatre in 1993 under the collective title The Bald Trilogy (that's as opposed to The Hare Trilogy, which was packing them out in the Olivier around the same time). And in last year's Mystery Bruises, based largely on his previous TV series, Reality on the Rocks, he looked at the wonders of the universe, and the other universes which peek through into it from time to time.
Campbell characterises the world-view that informed these brilliantly hilarious, disjointed and at times faintly threatening safaris into his hinterland as "science-fictional", and can place his conversion to this way of seeing fairly precisely: it happened in the Station Hotel at Newcastle- upon-Tyne in 1971. At the time, he was touring with Ken Campbell's Roadshow, an anarchic band of performers (including, among others, Bob Hoskins and Sylvester McCoy) who went around theatres, pubs, working-men's clubs and anywhere else that would have them, performing sketches, putting ferrets down their trousers and doing anything else they could think of that would get a laugh. In the Station Hotel, Newcastle-upon-Tyne, Campbell came across a convention of science-fiction writers and found that he enjoyed the company of the authors tremendously. "We never used to go to bed at science-fiction conventions, we just used to talk the whole night away. And they didn't argue, that was the great attraction: you'd say something and they'd say `Yeah, yeah and... have you thought of that?' "
This new interest in exploring other worlds, or other views of this world, led some years later to the founding of the Science-Fiction Theatre of Liverpool, a company whose productions included the epic Illuminatus! - which was invited to be the first production at the National's Cottesloe Theatre - and the even more epic Warp, a 22-hour exercise in boosting sales of haemorrhoid cream.
It was after The Bald Trilogy that Campbell was phoned up by Windfall Films, who felt that he might be suited to fronting a series aimed at ferrying the public to the wilder shores of modern theoretical physics. He says that he was, at first, reluctant: "I told them `I'm not that interested really, I'm into science-fiction, crank science, pseudo-science, that's my area...' " But he was persuaded, and found that his assumption that this unfitted him for the job was mistaken: "As a matter of fact, it was boggling. What you were supposed to suppose was every bit as remarkable as every bit of crackpot and pseudo-science by the time you got to it." The result was Reality on the Rocks.
His powers of supposition only failed him when he met David Deutsch, an Oxford physicist who told him that there are more universes than there are quarks in our universe (bear in mind that there are more quarks in an atom than there are grains of sand on Bournemouth beach). "So I said, `What do you mean? Are there an infinite number of other universes?' He said, `No, not infinite. A large number, certainly.' " Apparently, Deutsch also told him that he makes money on the side through cryptography: the only really safe place to hide information is in a parallel universe, and only Deutsch and a couple of others know the technique.
In Brainspotting, Campbell rubs shoulders with, as he puts it, "enough brains to fill a bathtub": zoologists, neurologists, psychologists, and lots of philosophers - including Marvin Minsky (author of The Society of Mind - "Marvin Minsky's super"), John Searle (Intentionality - "He's excellent") and Derek Parfit (Reasons and Persons - "I wouldn't say jovial, but he was very pleasant to be with"). He evidently likes philosophers. Unfortunately, as he admits, "You can't pass exams like that, can you, on who you know? They don't say `Give him an A, he's met Minsky'." He also meets several people with interesting brain disorders, including Becky, an American woman with 17 personalities: "You must never call her Rebecca, because if you summon up Rebecca, that's the one that attacks people with knives and guns."
Does all this add up to an answer? Do we understand how our brains work? Probably not. But if we don't know for certain, the next best thing is to keep an open mind: Ken helps us to do that.
n `Brainspotting' starts 9pm Sun, C4Reuse content