One of my favorite classes at Harvard was “Nature, God and Religion”, taught by James R. Moore, a visiting lecturer in the History of Science Department. Jim, a leading expert on Charles Darwin’s life and cultural context, always made complex ideas seem accessible and lively, giving us a taste of the radical zeal that inspired 19th-century thinkers who grappled with the relationship between science and religion.
 
Jim and his colleague Adrian Desmond have collaborated on several books about Darwin, the latest being Darwin’s Sacred Cause, available now for pre-order from Penguin Books UK. In this study, they argue that Darwin’s passionate opposition to slavery motivated him to seek a common ancestor for all human races, countering the conventional wisdom that non-whites were distinct and inferior species. Here’s an excerpt from Jim and Adrian’s fascinating interview on the Penguin Books website:

What was the initial spark that inspired you to write a book arguing such a revolutionary thesis?

We asked the big question in our 1991 Darwin biography: “Why did such a rich and impeccably upright gent go out of his way to develop such a subversive and inflammatory image of human evolution? He had everything to lose!” But we only partially answered it, showing how Darwin covered his tracks and kept ominously quiet for thirty years on the subject, before publishing The Descent of Man in 1871. The question kept niggling: `Why did he do it – and why did he wait so long?’ We knew that contemporary radicals, Christian and otherwise, had opposed slavery, and then it dawned on us that the Darwin family’s anti-slavery brotherhood beliefs could have driven the ‘common descent’ approach of Darwin’s particular brand of evolution.

About ten years ago our thesis began to jell. Jim was particularly interested in The Descent of Man, which no one seemed to have read. Why was two-thirds of a book supposedly about human evolution devoted to beetles, butterflies, birds and furry mammals? Darwin’s answer was: to prove his theory of `sexual selection’. But why was sexual selection so important to Darwin? Jim’s answer: because it was his prize explanation of racial common descent – why black people and white people looked different but were still members of the same family, not separately created species, as pro-slavery demagogues were arguing. Meanwhile Adrian realized how Darwin’s work on fancy pigeons and hybrids, leading up to sexual selection, also served to undermine pro-slavery science. What’s more, Darwin had originally intended all of this to go into his great work on evolution, which was finally published as The Origin of Species – a book that everyone knows `omits man’. No Eureka moment for us, then, but a lot of loose ends came together to tie a gloriously satisfying knot.

2009 is the Darwin Bicentenary, as well as the 150th anniversary of the publication of his Origin of Species. Why has it taken so long to discover the moral motivation behind Darwin’s theories of sexual selection and human origins?

The Descent of Man hasn’t been read, much less read carefully. Over and over, scholars have called it `two books’ crushed together (and it is unwieldy, over 900 pages). That’s one reason. Another is this: only in the last generation have Darwin’s private notebooks, letters and marginal jottings become fully available. Without these, it was difficult to trace the development of his views on human origins. Above all, though, there has been great reluctance to see Darwin as more than a heroic `genius’ uncovering pure gems of `truth’ beyond the vision of ordinary mortals.

To most of his admirers, Darwin was a `great scientist’ getting on with a great scientist’s proper job, not a Victorian gentleman with a moral passion making all life kin by solving that contemporary `mystery of mysteries’, how living species originate. But historians today see Darwin quite differently: they emphasize the social and historical context that made it possible for Darwin or anyone to craft a theory from available cultural resources. One such resource in Darwin’s world was anti-slavery, the greatest moral movement of his age. Our thesis is that the anti-slavery values instilled in him from youth became the moral premise of his work on evolution. Many scientists and philosophers think that explaining genius and its insights as we do saps the power of science and, given the challenge of creationism, is an act of treachery. The reluctance to dig beneath the surface of Darwin’s books into the social and cultural resources of his times is as dogged as ever.

And why is Darwin’s moral motivation important?

This is perhaps the most radical and upsetting idea: that there was a moral impetus behind Darwin’s work on human evolution – a brotherhood belief, rooted in anti-slavery, that led to a ‘common descent’ image for human ancestry, an image that Darwin extended to the rest of life, making not just the races, but all creatures brothers and sisters. In his family `tree of life’, all share a common ancestor. It’s vital to realize that Darwin’s science wasn’t the `neutral’, dispassionate practise of textbook caricature; it was driven by human desires and needs and foibles. Even our most vaunted theories – such as human evolution by a common descent with apes and all other creatures – may be fostered by humanitarian concerns. This throws all Darwin’s work – so vilified for being morally subversive – into an entirely different light.