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.
How long did it take for the book to come to fruition?
Our gestation goes all the way back to Darwin in 1991, and to our separate but parallel interests in anti-slavery beliefs (in Adrian's case) among radical anatomists, and (in Jim's case) among the evangelical ethnologists that helped Darwin make his case for sexual selection. But we didn’t really get going on the project until ten years later, when we started writing the introduction to (and editing) the Penguin Classics edition of The Descent of Man. This was published in 2004, and by then we knew that we had only scratched the surface of a very deep subject. As the 2009 Darwin bicentenary approached, our work took on a life of its own, and after starting Darwin’s Sacred Cause about two years ago, we clinched the 'common descent' angle and pieced together how Darwin's research for the book that became The Origin of Species effectively combated the rising `scientific racism’ in America and Britain.
What sort of research did the book involve?
Loads. That’s number one. Everything we’ve done separately and together for decades got poured into Darwin’s Sacred Cause. But our new research was prodigious. Jim spent weeks one scorching summer in the English Potteries, ploughing through faded, cross-written, semi-decipherable Darwin family correspondence, literally thousands of letters and other archival materials. Most of his other digging was local, in the vast Darwin archive at Cambridge University Library, but a trawl of the National Archives at Kew netted the logbooks of HMS Beagle and other ships, which shed fresh light on Darwin’s face-to-face encounter with slavery in South America. Adrian meanwhile ransacked the esoteric breeders’ literature that Darwin read, on cattle, pigeons, poultry and the like; and he tackled the racist propaganda that riled Darwin, and much else besides. Darwin’s Sacred Cause may be one of the first historical studies to exploit the rich nineteenth-century sources recently made available on-line: for instance, newspapers from the British Library and the House of Commons Parliamentary Papers yielded wonderfully fresh contextual material for our thesis.
What do you think is the most surprising element of this book?
Our revelation that much of Darwin’s research over many years was about race. There was no ultimate difference for Darwin between a `race’ and a `species’, so his work on `the origin of species’ was also about the origin of races, including the human races - `man’ was never an exception for him. And while most of Darwin’s research was implicitly about human origins, the extent of his explicit interest in combating racist science is a real surprise. The fact that his most intense phase of work on racial questions came as the United States hurtled towards civil war, a war that the humanitarian Darwin dreaded, adds poignancy to the moral dimension of his research.
What sort of reaction are you anticipating from the scientific community? The history community? The evangelical community?
Many scientists will welcome a `moral’ Darwin’ to confound his religious critics; others will resent our polluting Darwin’s pure science with `extra-scientific’ factors and will declare his anti-slavery beliefs irrelevant. Historians may be more positive, if only because Darwin’s Sacred Cause locates Darwin for the first time on the well-trodden historical fields of transatlantic slavery, slave emancipation and the American Civil War. And those who study the history of `scientific racism’ will have a new Darwin to reckon with. Evangelicals may feel distinctly queasy, not least because William Wilberforce, the Clapham `Saints’ and others they revere as religious ancestors once supped happily with the freethinking Darwins and saw them as allies in the anti-slavery crusade. Darwin’s words, `More humble & I believe true to consider [man] created from animals’, will pose a challenge to every creationist.
What lessons does this book contain for the relationship between religion and science?
That `the relationship between religion and science’ never existed; that religion in science was the norm in Darwin’s day, and he never escaped its aura; that biological theorizing about human nature inevitably poses moral questions, and in so far as these questions have religious answers, to that extent `religion and science’ are inseparable.
When readers close Darwin’s Sacred Cause after finishing it, what do you hope they will be thinking?
`Gee, I didn’t know that about Darwin.’ `I never dreamt he cared.’ `Maybe evolution has something going for it after all.’ `Next time at the zoo, maybe I’ll drop in on the relatives.’