An outrageous optimist finds freedom in the cells

He studies the human condition through robots and computers, but philosopher Daniel Dennett still finds plenty of time for the good life.

For, as he tells Laurie Taylor, nature's raw materials have made us wonderful things, and evolution will make us ever freer

I first became aware of Daniel Dennett in the early 1980s. He seemed to have become something of a fall guy in John Searle's joyous philosophical lampooning of those who had been sufficiently impressed by the power of the digital computer to suggest that the mind was nothing more than a particular sort of computer program. But instead of backing away from Searle's hailstorm of invective, Dennett advanced into the fray. He happily announced his intention to work on the design of a "cognitive robot" and cavalierly published The Practical Requirements for Making a Conscious Robot . In this work, he claims that if a robot "develops to a point where it can conduct what appear to be robust and well-controlled conversations in something like a natural language, it will certainly be in a position to rival its own monitors as a source of knowledge about what it is doing and feeling, and why".

In articles and interviews, he insisted that his fascination with computers - one reviewer observed that Dennett had probably never met a robot he didn't like - was not evidence that he had deserted the field of philosophy. Far from it. "Computers keep you honest in a way that philosophers have been hankering after for a long time. Computers force you to get clear about things that it's important to get clear about.

Artificial intelligence is really a new and better way of doing certain sorts of philosophy."

The image of Dennett that one gets from all this is of a rather austere desiccated chap with a perverse predilection for chatting to computers.

But, in recent years, his wonderfully readable and provocative books on evolution, consciousness and free will have earned him the respect of a formidable list of high-powered intellectuals. Richard Rorty rushed to praise his "extraordinarily lucid argumentation", Steven Pinker credited his "twinkling wit", Richard Dawkins referred to his writing as a "torrent of stimulating thought", while a reviewer at The Sunday Times was sufficiently moved by his mastery of so many disciplines to declare: "If anyone can claim to be the Leonardo of the New Renaissance, Dennett can."

He certainly looks the part. When I turn up to talk to him about his latest book, Freedom Evolves , I am faced not by the austere computer buff of my imagining, but by a tall, powerfully built man with a flowing Hemingway beard. Dennett looks for all the world as though he should be out at sea wrestling with marlin rather than trawling round radio studios trying to explain the conceptual difference between determinism and inevitability. He rather enjoys my surprise. Yes, he tells me, his critics often expect that someone who has devoted so much time to finding a naturalistic account of the mind, to looking for resemblances between computer thought and human thought, will have a mechanistic temperament. "They're so puzzled when they find that I'm a sculptor and an amateur musician, that I live on a farm in Maine, where I harvest blueberries, hay and timber and make Normandy cider wine when I'm not sailing, when they find that nobody loves life more than me, nobody more appreciates the aspects of life that they think I'm ruling out. They say, 'Look at all the fun he's having. This is the man who says there's no such thing as fun.' But that's not what I say. It's just their caricature."

I suggest to him that he rather enjoys shocking people. Wasn't there a conscious desire to annoy in some of his writing on computers and consciousness? "It's always fun to shock and outrage. That's what philosophy is supposed to be about. We're supposed to shock people out of bad habits of thought into new habits of thought. That doesn't mean we don't need logic and discipline. But they should be in the background.

They're not the show, they're the girders that hold the stage up while the show happens." Did this mean that he was happy to be called a populariser? "I think that one of the worst things that's happened to philosophy in the past 100 years is its professionalisation, where philosophers talk to each other, to little coteries of self-styled experts, in a jargon that becomes a code. I think that the discipline of having to explain an idea to an uninitiated person is essential. I think if you cannot explain what you are doing to a bright undergraduate, then you don't understand it yourself."

That sounded like a cue. In the absence of a bright undergraduate, would he mind explaining the central thesis of his latest book to a sceptical sociologist? What did he mean, for example, when he described himself as a "naturalist"? "Look. It's too late in the day to hold any view other than this. Each of us is a collection of some 100 trillion little cells, little robotic cells that team together and sometimes form alliances and sometimes compete. Now, the organisation of these little cells is what we are. And somehow all the wonderful things that we do - our culture, our art, our consciousness, our free will - has to be composeable out of these raw materials without any wonder tissue, without any mysterious new stuff. And that's the tall order. That's the quest. That's naturalism right there."

It was at this point, I suggested, that his critics began to mass. They suspected that naturalism wasn't so much about scientifically explaining matters such as free will and consciousness as diminishing them or defining them out of existence.

"That's right. They are made anxious by the thought that if science shows, as it were, that there is nobody home in a human body, then there is nobody to blame and there is nobody to take pride in glorious acts of heroism either. So the task for the naturalist like me is to show how there can still be persons without being Cartesian persons, without there being a little immaterial soul that animates and controls the body like a puppeteer. That is a hard thing to show, but I think I can."

But if he was going to reassure people about his intentions, didn't he also have to deal with the question of determinism? Any naturalistic explanation of free will necessarily run up against the problem of how anything described as "free" could be subject to the deterministic rules of science.

"Absolutely. And here my main task - and it feels like moving a mountain - is to get people to realise that determinism and inevitability are not synonyms. There is no interesting relationship between determinism and inevitability. If your world is determined, it doesn't mean that your future is inevitable. The way to get at this is by taking the word 'inevitable' and looking at what it means. It means unavoidable. Its opposite is avoidable or evitable. So, what you have to show is that if you have an evolutionary process in a deterministic universe, then what you get is growth and the eventual explosion of evitability. More and more things become avoidable. What is ironic is that it is the very predictability that science gives you that increases the evitability. It is because we can foresee the outcomes of various circumstances that we can take action to avoid them, and the reason that we are so much more free than other organisms is because we can see farther into the future because we have more knowledge."

But is this not a very benign or contrary reading of evolution? In his book, Straw Dogs , John Gray had surely drawn a more pessimistic conclusion from the workings of evolution, the conclusion that any attempt by human beings to mark themselves off from animals by virtue of their capacity to display foreknowledge and indulge in planning was presumption and vanity.

"I've read Gray's book. It's a panicky oracle. I kept thinking, 'Why is he so unbalanced by what he thinks he's learnt from Darwin?' It is not romantic exceptionalism to note the differences between the human species and other species. We're very different from other animals. Yes, we have failed projects, but no other species has projects. And yes, we have a lot of failed projects. But we also have a lot of projects that work. There are phenomena in the world that are probably best addressed by dour, paranoid, cynical, tired minds, but there are other phenomena that are best addressed with a real optimistic view."

"And you are one of those best suited for the latter sort of work. You are an optimist. You relish life?"

"Absolutely. I am an archetypal American optimist. There is no doubt about that!"

I glanced across at him as I switched off the recorder. He was sitting quite still. Funny really. I'd half expected to see him raising his hand and punching the air.