Discourse: Have Evolutionary Explanations Gone Too Far?

Jeremy Stangroom

In July 1998, TPM attended a paper given by Professor John Dupré at the Mind/ Aristotelian Society Joint Session titled 'Against Reductionist Explanations of Human Behaviour' (see TPM4). We felt that the topic of this paper deserved a wider audience, so we approached Professor Dupré and asked whether he would be willing to take part in a public debate about the issues that he raised. He agreed, but it wasn't until a year later that we found a suitable opponent, in the guise of Dylan Evans, a research student at the London School of Economics, and author of Introducing Evolutionary Psychology. In addition to the two main protagonists, we were very pleased to welcome Booker Prize winning author, Ian McEwan, as chair for the event, which took place at Borders Bookshop on London's Oxford Street.

McEwan opened proceedings by talking about the explosion of interest in evolutionary psychology. 'I have stood back amazed,' he admitted, 'especially in the last ten or fifteen years, as things that were once simply the preserve of poets, philosophers and fiction writers, have been drawn into the great maws of experimental science. Things like reputation, gratitude, cheating, and on a grander level, human beauty and beyond that to mind, consciousness and human nature. These were once not respectable subjects for scientific enquiry, but in twenty years this has all changed.'

But he noted that evolutionary psychology has its detractors. People argue that, in the absence of hard evidence, it depends too much on a priori, armchair musing. And further, that the kinds of theories that it does put forward do little to add to our understanding of human behaviour. He finished by pos ing a question: what has evolutionary psychology taught us about human nature that we might not have already known?

Dylan Evans began by noting that science has always had to face down its detractors. 'They sit, Canute like, on the sands of obscurantism, shouting in vein at the advancing tide of knowledge. "Get back! Come no further! Leave me this little piece of unexplained territory!" Thankfully, science takes no notice. The Promethean spirit that animates scientific enquiry, that terrifying curiosity that inhabits the human soul, always proves stronger than the fear of knowledge that opposes it.'

He pointed out that when evolutionists first suggested, sometime before Darwin, that humans had descended from non-human species, they were the target of this kind of reactionary criticism. However, in the case of evolution, the criticism has not gone away. Evans noted that 'although the evidence for evolution is overwhelming today, there are still those who ignore it. Over half the US population still believes in the literal truth of Genesis. Thankfully, the population in the UK is somewhat more enlightened on this matter. Few people here seriously doubt that we evolved from other life forms. But even in the UK, there is still a widespread reluctance to take this idea to its logical conclusion, namely, that our minds are just as much the product of evolution as our bodies. This is Canutism. The new Canutes admit that the tide has come further up the shore. Science has already claimed the human body as its own, they recognise, but please don't let it claim the human mind.'

But, he insisted, it simply isn't possible to separate out the body from the mind. 'What is the mind after all, if not the activity of the brain? And what is the brain, if not a biological organ, the product of evolution like any other organ?

'Unless we want to fall back into a long discredited Cartesian dualism,' he insisted, 'we must admit these simple facts. The mind, like the body, is the product of millions of years of natural selection and historical accident. This means that there simply must be some kind of evolutionary psychology. The only real question is how to go about doing it.' He concluded, therefore, that it wasn't the case that evolutionary explanations have gone too far, rather they haven't gone far enough.

John Dupré began by making it clear that he is not against evolutionary explanations per se, stating that as far as he is concerned 'evolution is the explanation of existence, the diversity of life and many other things.'

But what he does oppose is much of the work that goes under the name of evolutionary psychology, arguing that it is both empirically and theoretically suspect. Specifically, he claimed, evolutionary psychology 'has a deeply flawed theoretical framework. It tends to start off with a number of wildly simplistic, or perhaps I should just say false claims, that unfortunately are widely believed, which gives some currency to what then is said to follow from them.

'At the core,' he argued, 'is a pyramid of false claims, which very briefly are:

1. Natural selection selects genes

2. Genes build brains

3. Brains cause behaviour

All these claims are massively simplistic, indeed I would say false, at least false in the way that they are normally interpreted.

'I'll just mention one of the problems,' he continued, 'for the purposes of illustration. Take the claim that genes build brains. Genes, of course, do nothing of the kind - it would be just as true to say that wombs build brains or schools build brains. In fact, it takes a combination of these and many other things to build the brains that we hope to find in the people that we meet.'

But Dupré was keen to emphasise that he did not endorse a 'blank slate' view of human nature, that is, the view that human nature is infinitely malleable. 'It is rather to say that the matter is much more complicated than evolutionary psychologists suppose. It involves an interaction between many factors, and the sort of canonisation of genes in this process represents a quest for simplicity that the phenomenon just won't bear.'

He concluded by offering a tongue in cheek, evolutionary psychological hypothesis to explain this quest for simplicity. Stone Age people, he argued, at some point developed complex languages that enabled them to ask questions about their existence. But there were very great pressures on their time, so it would have been advantageous for them to develop simplistic answers to the big questions, to allow them to get on with the important business of reproducing and feeding themselves. And, of course, those who did develop simplistic answers rapidly out-reproduced their more sophisticated rivals!

'I just hope,' he concluded, 'that cultural evolution will enable us to overcome this atavistic defect of our nature and accept that some things are just more complicated than they might at first seem. And we have to be prepared to look at many factors interacting if we're going to understand what we are like and where we came from.'

Evans responded by arguing that evolutionary psychologists are well aware of the importance of environmental and cultural factors in the determining the effects of genes. 'We all agree,' he claimed, 'that genes only build bodies in a certain context. In a sense, we're all interactionists now ... so I think John is slightly mischaracterising evolutionary psychology, when he says that evolutionary psychologists don't recognise this fact.'

But Dupré was not convinced. 'It seems to me that the privileging of genes is absolutely essential to the whole evolutionary psychology project. If one doesn't privilege genes one has no rationale for the assumption that the way to understand our behaviour is to think about what happened two million years ago. Genes are presented as the thing that couldn't have changed much in the intervening time, so the claim that we still have Stone Age brains depends on the belief that brains are basically built by genes.'

One of the fears that people have about evolutionary psychology is that it might lead eventually to eugenics. Did the speakers share these concerns?

'It seems to me,' replied Dupré, 'that there are serious ethical dangers in allowing so-called scientific experts tell us what is possible and what is not possible for human societies. And enthusiasts for evolutionary psychology do tend to say things that I find rather distressing. For example, Dylan says in his book, "For each acquaintance we keep a mental tally of how much they have done for us and how much we have done for them". Now that is the sort of thing that people are led to say when they reflect on these evolutionary models. And for me, this is an ethically appalling statement about human nature. No doubt to some degree it is true, but in many of our relationships, I hope that it is not true.'

Evans did not share these concerns. 'I think one of the most comforting aspects of evolutionary psychology is the emphasis that it places on altruism. Human beings, it tells us, are naturally co-operative creatures - high levels of altruism are in fact one of the distinguishing features of our species, shared only by a few others. Of course, it does not naively promote an over-optimistic view of human nature, rather it stresses that human altruism is a variable feature of human societies, which can be promoted or discouraged by institutions, cultural norms or even widely promulgated theories. Evolutionary psychology is not only scientifically valid, it is also morally sound for it discourages pessimism about human nature.'

A theme that ran through the discussion was the extent to which evolutionary psychology was backed up by empirical evidence. Evans admitted that more empirical work was required to get evolutionary psychology on a sure footing. However, he claimed that there already existed some impressive empirical studies. He pointed to a study of homicide patterns, which showed that in all the cultures studied there were very significant differences between the rate of infanticide by biological parents and by non-biological parents.

'If this is indeed a universal pattern,' he claimed, 'it does suggest that though culture is very active in shaping our behaviour, it is a mistake to assume that we are infinitely malleable by culture.'

Dupré conceded that the homicide study probably showed some innate disposition to be nice to our biological children. 'But,' he concluded, 'isn't the interesting question to find out why a very small number of people hurt or murder children, rather than producing a statistic that leaves us no wiser about how biological and cultural factors interact in the production of the phenomenon.'