LONDON — Charles Darwin is widely thought to have developed his natural selection theory of evolution after noting differences among finches in the Galapagos Islands.
But it was variation in another species the young British naturalist observed during his now-famous voyage on the HMS Beagle — man — that actually drove his breakthrough, a new book argues. And the inspiration for that insight may have been Darwin's fervent antislavery views and moral passion to show that men of all races were brothers.
"Everyone says the Galapagos are everything, which is more or less rubbish," said James Moore, a Darwin biographer and co-author of the new book.
The ideas in Darwin's landmark book, On the Origin of Species, remain at the center of deep philosophical and religious debate a century and a half after they were published.
Why did Darwin "touch the untouchable" by developing a theory that "was an abomination to a Christian gentleman naturalist who needed career advancement and respect?" asks Moore, who holds degrees in divinity, history and science.
The answer, he argues, is basically that Darwin, raised in a family that considered slavery a sin, believed wholeheartedly in "the brotherhood of the races" and was able to imagine a family tree that united them and the mechanisms that led to their differences, unlike other thinkers of his time.
"He was quite unlike the modern 'disinterested' scientist who is supposed … to derive theories from 'the facts,' " Moore and co-author Adrian Desmond suggest in their book, Darwin's Sacred Cause.
Moore, 61, who was raised in a "real Bible-banging" family and originally saw Darwin as an enemy, wrote a doctoral dissertation on the controversies provoked by Darwin's work and eventually became an admirer of Darwin.
The new book, which Moore calls a "prequel" to his and Desmond's 1991 biography, Darwin, was inspired by a hunch about the reasons the naturalist pursued his radical theory of evolution. Moore, who now lives in Cambridge, knew Darwin came from a family strongly opposed to slavery that believed all human races were genealogically related.
Recent digitalization of records in Britain, particularly ship logs from Darwin's five-year Beagle journey, also shed light on his firsthand encounters with slavery, his growing awareness of the range and adaptability of humans, and his recognition that widespread struggle existed among people and races from South Africa to Tahiti to Tierra del Fuego.
Those experiences may have led to his breakthrough that evolutionary change was driven by competition for survival, a mechanism he called "natural selection."
Documents show that the differences between Darwin's Galapagos finches were pointed out to him by a colleague only months after he got back from his voyage. Darwin hadn't bothered to note his bird samples came from different islands, Moore said.