Charles Darwin and Abraham Lincoln have been spotted together a lot recently — in a book by the New Yorker’s Adam Gopnik, in a George Will column, even on the cover of Newsweek — because they happen to have been born on the same day 200 years ago: Feb. 12, 1809.
After noting that coincidence, however, commentators often miss the most direct connection between the bicentennial birthday boys: Each, in his own way, fought vigorously against slavery.
Contrary to myth, Lincoln was late to adopt the cause of emancipation. His goal at the outset of the Civil War was to save the Union, not to free the slaves. Darwin, though born into a family of dedicated British abolitionists, was similarly slow to rise in opposition to the worldwide trade. He did not become passionate about it until he saw slavery up close in South America during his expedition aboard the Beagle in the 1830s. But his contribution to the cause, though more philosophical and less immediate than Lincoln’s, was no less profound.
In “Darwin’s Sacred Cause,” Adrian Desmond and James Moore contend that abhorrence of slavery inspired and shaped Darwin’s theory of evolution. To grasp his grand project, we have first to understand one of the great scientific battles of the mid-19th century.
“Polygenists,” such as the American physician Samuel George Morton, held that the human races were each a distinct species. They considered Anglo-Saxon whites superior in every way to the “debased” and “savage” darker races, which were relegated to a supposed natural position of servitude.
Darwin, a man of his time, also believed in the superiority of whites. But he was convinced that all humans were one species, and that those not born to English manners could be improved through education. With growing horror, he observed slavery in Brazil and the genocide of indigenous peoples in Argentina, and decried both in his “Voyage of the Beagle”: “It makes one’s blood boil, yet heart tremble, to think that we Englishmen and our American descendants, with their boastful cry of liberty, have been and are so guilty,” he wrote in the 1845 edition of his popular travelogue.
Fourteen years later, when he published “On the Origin of Species,” Darwin described the evolution of plants and animals but not of humans. This famous omission has been variously ascribed to an abundance of caution, concern for his wife Emma’s religious sensibilities or even a preference for bugs and finches over his own species.
But Desmond and Moore make the case that human evolution was at the forefront of Darwin’s thinking. By proving that all animal species descend from common ancestors, Darwin hoped to undercut the biological rationale for slavery without the need to draw distracting fire by addressing human origins directly, especially before he had amassed all the data he would need to prove decisively that humans also evolved.
“Human evolution wasn’t his last piece in the evolution jigsaw; it was the first,” Desmond and Moore write. “From the very outset Darwin concerned himself with the unity of humankind. This notion of ‘brotherhood’ grounded his evolutionary enterprise.”
In lesser hands, this recasting of Darwin’s life as an extended anti-slavery campaign could seem like a stretch. But Desmond and Moore, professional historians of science who are widely regarded as Darwin’s finest biographers, follow Darwin’s example by deciding that the best way to prove a controversial point is “to pile on crippling quantities of detail.”
Drawing on his manuscripts, notebooks, letters and even marginal jottings in books, they construct a theory of both broad scope and meticulous documentation, leaving critics with few holes to probe.
If Darwin’s intent was to prove the biological connectedness of all humanity, then he succeeded brilliantly; he demolished the scientific justification for slavery prevalent in his time. Yet, ironically, more than a few bigots and crackpots have tried to use his ideas to justify further racism, starting soon after the publication of “On the Origin of Species” with the vogue for “social” Darwinism. Darwin detested those attempts, which were so at odds with what Desmond and Moore call his “sacred cause.”
Two hundred years after his birth, Darwin has been vilified by some, sanctified by others and, perhaps, misunderstood by most. Rich in detail, remarkably readable and engaging, Desmond and Moore’s reassessment may do no more than other books to convince evolution’s deniers of the grandeur of Darwin’s view of life. But by revealing the motive behind his work, “Sacred Cause” is the finest birthday tribute to Charles Darwin in many years.
Thomas Hayden is co-author of “Sex and War: How Biology Explains Warfare and Terrorism and Offers a Path to a Safer World.”
