QUESTION to Pinker and Rose: What experimental scientific procedures would you do to determine which of your theories is correct?

PINKER: For approaches of this magnitude there isn't going to be one experiment that's decisive. The proof is going to come from the entire body of research that's inspired by the general idea: the hypotheses that flow out of the theory and the ability of the theory to make correct predictions in a wide variety of domains that mutually cohere and that wouldn't have been made otherwise. One of the main points in How the Mind Works is that there has been an enormous body of experimental literature that has been generated by the hypotheses that I present and that hang together well. Any one of them could turn out to be false and require reinterpretation, but it's our general understanding of the emotions and memory and visual perception and so on over a long period that will determine whether we hang onto that approach as basically sound.

ROSE: I don't think that theories are ever overthrown by decisive experiments. Their protagonists merely fade away, despite what Karl Popper said. However there are two sorts of experiments or pieces of biological information I would like. One is very specific: I would like to know why it is that although we share 98% of our genome with chimpanzees no one can mistake the phenotype of a chimpanzee with the phenotype of a human. And the second, and it's a much more easy question to answer in some ways, is the information-the understanding that's coming-on mapping mental processes that come out of the windows into the brain which are provided by positron emission tomography, magnetoencephalography, and all the other technologies that there are around at the moment, that are bound to give us a richer understanding than the rather crude mechanistic models that we all share of the way minds and brains work at the moment.

QUESTION to Pinker and Rose: Both speakers espouse the idea that we have active control over what we do and what we don't do. I've got a bit of a problem with that. For myself and what I see in other people, we operate within very strictly controlled parameters. So I just wonder why in both your investigative researches, there hasn't been more emphasis on what we might call simple preference, such as why you've both got different hairstyles and wear different suits.

PINKER: I'm not sure I understand the question.

ROSE: I'm not quite sure why Steve wants (as he was described in The Guardian a few days ago) his hair to look so beautifully like a bouffant rock star . On the other hand I do think you're right to speak about the constraints in which we operate. I've given the impression that we are free agents, but of course we're not free agents; we're bound socially, we're bound economically, we're bound culturally, we're bound historically, and we're bound biologically, so the constraints which all of those provide-and they're much much sharper, despite what Steve says, for unemployed workers than they are for company directors, and much sharper for black footballers than white racists on the terrace, again a point he seems to disapprove of, and a point I made in the book. I think those are the constraints in which we need to operate, and those are the constraints which I think a different sort of science than either Steve's or mine needs to try to understand.

PINKER: The point I made concerning people with different social backgrounds is not that they have equal choices in life, which they obviously don't. I was raising a specific point as whether that affects the scientific metaphors and analogies that they take seriously, and I think that there's no evidence that they do and some evidence that they don't.