ROSE: It depends what you mean by Darwinian ideas, which is one of the problems. Darwin's basic idea is very straightforward. What is not controversial is that evolution occurs. What is at issue is the mechanism of evolutionary change. And the Darwinian evolutionary process says something which is also incontrovertible, that like breeds like with variations, that all organisms produce more offspring than can survive into adulthood and reproduce themselves. Those variations which are best able to survive are more likely to survive into adulthood and breed in their turn, so you get evolutionary change like that. No question. That's one of the fundamental mechanisms of evolutionary change.

But if you read Darwin himself, he was very clear that there are others as well. Sexual selection is one, random changes are another. And chance — the issues that Steve Gould calls contingency — becomes very important here as well. Darwinian mechanisms are very good for species getting better at what species do, but they're not good at making new species. Darwin himself was very well able to recognize this which is why the Galapagos became very important. Here were islands very close together populated by species which seemed similar but had particular differences from island to island.

Much later when he was looking at the specimens that he'd got from the different islands, particularly at finches of which there are generally agreed to be 13 different species in the different islands, Darwin came to the conclusion that what must have happened is that the original parents of all these finches had come from the mainland, from Ecuador, which is about 400 miles to the east. Once they were on the islands, they bred and they radiated out. In the different islands there were different potential foods available and the finches became more specialized accordingly — some of them are cactus eaters, some of them are insect eaters, some of them are ground finches, there's a woodpecker finch, there's An insect eating warbler finch, and so on. All which probably came from the same original stock. This is one way in which new species were produced, by arriving in a virgin territory and then radiating out from there. So all these mechanisms become very important as far as evolution is concerned.

Now we come to the question that you were asking, which is about the evolution of humans, and the relationship between our brains and our brain processes and evolutionary mechanisms. We are evolutionary products. The particular evolutionary line which has led to humans has been one which has achieved species success by the individuals developing bigger and bigger brains. Now brains aren't necessarily the only way to evolutionary success — bacteria (Lynn Margulis would say proctista) outnumber us, and will probably outsurvive us in the world. But once you start on the evolutionary line which leads to brains, once you're an omnivore, you have to hunt your prey, or you have to learn to escape from prey, then there's an evolutionary pressure to get smarter — that's the route that led to humans.

What our evolution has given us is brains which are enormously powerful and adaptive, capable of enabling us to live in the very complicated social circumstances in which we do, and capable of creating our own history and our own technology. There's a lot of debate which you get from the ultra-Darwinians about free will.

Richard Dawkins ends one of his books by talking about the power of humans, that only we can escape the tyranny of our selfish genes. Somehow free will rescues from the sort of determinism which is given by our genes. I don't look at it like that.

I don't take free will very seriously. I would say something different, and that is that we have to get rid of this whole attempt to create dichotomies between nature and nurture. The real thing about our brain development, our development as organisms, is not a dichotomy between nature and nurture, but a dichotomy between specificity and plasticity or perhaps between process and outcome. What is required is a developmental system which is partly not modified by the environment and partly capable of responding to the environment.