In January 1830 a young Scottish shepherd walked 21 miles through the snow from Wick to Thurso to hear a lecture on "light, heat, and the electric fluid". History does not relate how good the lecture was but Alexander Bain was convinced; he became an inventor, made the first electric clock, and the first ever fax machine - not that anyone had much use for fax machines in the mid-19th century. But I mention him only for his heroic walk. Was it normal in those days for people to make such efforts to attend a scientific lecture?
They would not now, would they? Not in these days of television, radio and the World Wide Web. Not when they can get all the science they want without stirring from their own armchairs. Not when science itself is so often despised. Not when going to a lecture theatre to hear someone talking is so old-fashioned.
That is what I would have thought, but I was proved wrong when I was recently asked to chair a debate between two scientists. The 100-seater lecture theatre was packed solid and the pounds 10 tickets were sold out more than a week in advance. Clearly people wanted to be there. But why?
The two protagonists were Professors Steven Pinker, a psychologist over from the United States to promote his new book How the Mind Works (modest little title), and Steven Rose, a biologist from the Open University. They have very different views of human nature.
Both are committed evolutionists, and both are concerned with understanding how the mind works. Nor do they differ over the morality of evolution - neither would succumb to the "naturalistic fallacy" - confusing "is" with "ought" - or assuming that because something is natural it must be good. But their differences are nevertheless fundamental, and concern the nature of the human mind itself.
For Professor Pinker, the mind is what the brain does - and that is computation. The brain is a modular computing device, something like a Swiss army knife with modules evolved for different functions, including vision, problem- solving, or finding sex and food. The driving force behind all human behaviour is ultimately the competition between the genes - not that every action is intended to spread our own genes, but that our behaviour reflects a mind that was originally designed by the genes. We evolved over hundreds of thousands of years as hunter-gatherers. So genes that would have aided survival then are the ones that still shape our brains and minds now.
To give a classic example from evolutionary psychology; the reason why women fancy big, strong, high-status men, and men fancy young women with fair hair and a low waist-to-hip ratio, is that people who had those preferences in the past had more children and passed on the genes that give them those preferences. In a similar way, Professor Pinker tries to show how our thinking, creativity and even religious beliefs have been shaped by the selfish genes.
Professor Rose accuses what he calls the "Ultra-Darwinists" of social naivety, of denying the complexity of life, and of fundamentally misunderstanding the nature of living things. For him the driving force in our lives is the freedom inherent in living processes. We humans cannot be reduced to the power of genes because we are integrated creatures with a self- determining trajectory through life - what he calls our "lifeline". We have the ability to construct our own futures, even though we cannot choose the circumstances.
People wanted to be at the debate because these issues - free will, identity and consciousness - lie at the heart of what it means to be human. I guess the emotions will always line people up on Professor Rose's side - preferring to believe in a real self who lives our life, feels the agonies and takes decisions with free will. But for me all the science lines up on Professor Pinker's side. Everything we do is either a product of what went before, or a matter of chance. What could this mysterious extra thing be, who, Professor Rose says, constructs its own future? No. I think science tells us ever more strongly that we humans are just products of the battle between the replicators and to think otherwise is an (understandable) arrogance.
Perhaps I will be proved wrong, but meanwhile I am glad that scientists are tackling these questions head-on and ordinary people are prepared to make the effort to come and join in. I do not suppose anyone walked 21 miles that night - and it was not snowing - but they did come from far afield. The good old-fashioned lecture is not dead yet (and thanks for the fax machine).
The writer is a senior lecturer in psychology at the University of the West of England.