Darwin's Dangerous Idea

Darwin's Really Dangerous Idea

Adaptation by natural selection is among the most successful and influential ideas in the history of science, and rightly so. It unifies the entire field of biology and has had a profound influence on many other disciplines, including anthropology, psychology, economics, sociology, and even the humanities. The singular genius behind the theory of natural selection, Charles Darwin, is at least as famous as his most famous idea.

You might think that my contrarian view of the limited power of adaptation by natural selection would mean that I am “over” Darwin, that I am ready to denigrate the cultural/scientific personality cult that surrounds Darwin's legacy. Quite to the contrary, I hope to celebrate that legacy but also to transform the popular understanding of it by shedding new light on Darwinian ideas that have been neglected, distorted, ignored, and almost forgotten for nearly a century and a half. It's not that I'm interested in doing a Talmudic-style investigation of Darwin's every word; rather, my focus is on the science of today, and I believe that Darwin's ideas have a value to contemporary science that has yet to be fully exploited.

Trying to communicate the richness of Darwin's ideas puts me in the unenviable position of having to convince people that we don't actually know the real Darwin and that he was an even greater, more creative, and more insightful thinker than he was been given credit for. I am convinced that most of those who think of themselves as Darwinians today – the neo-Darwinians – have gotten Darwin all wrong. The real Darwin has been excised from modern scientific hagiography.

The philosopher Daniel Dennett referred to evolution by natural selection – the subject of Darwin's first great book, On the Origin of Species by Means of Natural Selection = as “Darwin's dangerous idea.” Here I propose that Darwin's really dangerous idea is the concept of aesthetic evolution by mate choice, which he explored in his second great book, The Descent of Man, and Selection in Relation to Sex.

Why is the idea of Darwinian mate choice so dangerous? First and foremost, Darwinian mate choice really is dangerous – to the neo-Darwinists – because it acknowledges that there are limits to the power of natural selection as an evolutionary force and as a scientific explanation of the biological world. Natural selection cannot be the only dynamic at work in evolution, Darwin maintained in Descent, because it cannot fully account for the extraordinary diversity of ornament we see in the biological world.

It took Darwin a long time to grapple with this dilemma. He famously wrote, “The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!" Because the extravagance of its design seemed of nu survival value whatsoever, unlike other heritable features that are the result of natural selection, the peacock's tail seemed to challenge everything that he had said in Origin. The insight he eventually arrived at, that there was another evolutionary force at work, was considered an unforgivable apostasy by Darwin's orthodox adaptationist followers. As a consequence, the Darwinian theory of mate choice has largely been suppressed, misinterpreted, redefined, and forgotten ever since.

Aesthetic evolution my mate choice is an idea so dangerous that it had to be laundered out of Darwinism itself in order to preserve the omnipotence of the explanatory power of natural selection. Only when Darwin's aesthetic vies of evolution is restored to the biological and cultural mainstream will we have a science capable of explaining the diversity of beauty in nature.

 (From the book The Evolution of Beauty. How Darwin's Forgotten Theory of Mate Choice Shapes the Animal World – and Us. By Richard O. Prum).

Given that sexuality is an instinct is traditionally defined as a hereditary behaviour unique to a species, varying little from one member to the next, the variety of our sexual tastes is curious. Photograph by Elena.