Kicking off a day full of neuroscience is the review in the NY Times of philosopher David Livingstone Smith’s new book, Less Than Human: Why We Demean, Enslave and Exterminate Others. Those familiar with Smith’s work, for example Why We Lie and The Most Dangerous Animal, will not be surprised to find his original sin obsession in full bloom. That is, he’s continuing with his exploration of the underbelly of evolutionary psychology, this time describing the very uncomfortable intersection between human nature and genocide. Reviewer David Berreby’s conclusions are almost equally fascinating:

Dehumanization is a mind-set, as Smith writes, that “decommissions” our “moral inhibitions” about mistreating fellow human beings. Encased in law and custom, this psychological process has often licensed slavery, genocide and countless other cruelties.

Smith reasonably argues that dehumanization is rooted in human nature, not culture… Dehumanization is possible, Smith argues, because of “our cognitive architecture — the evolved design of the human psyche.” Our innate predispositions incline us to divide living things into species, he argues, and, with the same mental equipment, to divide humans into ethnic groups. And just as we do not believe that superficial resemblance means bats and birds belong together, neither do we trust that surface appearances determine who belongs where on the ethnic map.

In other words, in Smith’s account of the research, we are — for better or more often for worse — predisposed to believe that racial or ethnic identity is immutable. That’s because our instincts tell us it is based on an unchanging “essence” at each person’s core, rather than on changeable appearances. Philosophical experiments have shown, for example, that while most people feel sure that a 98-pound weakling can become a strongman, they also intuit that a black person can’t become white, no matter what physical characteristics he changes.

Smith clearly explains why many cognitive scientists believe this tendency is innate and then links it to another predisposition that seems “built in” to the human mind: our inclination to see living things in hierarchies, as in the “great chain of being” of medieval European Christians, with God at its perfect top, human beings above “higher” animals, and so on down to worms and plants. Because we feel that living things are defined by their essence, and because we feel that each creature has its rank in the world, Smith argues, dehumanization comes easily to the human mind: we accept that someone can look human but have a sub­human essence, and we accept that what is not human must be inferior. “When we dehumanize people,” he writes, “we think of them as counterfeit human beings.”


All these troubles arise because Smith’s insistence on immutable essences is only half right: people do categorize themselves and others using essences, but there’s nothing immutable about them. If, like trained philosophers, we could settle for good who is essentially human and who is a zombie vampire squid, we wouldn’t have, or need, this drama of dehumanization, rehumanization, then more dehumanization, and so on. Instead, the who-is-and-isn’t-human question is never truly settled. In fact, it is the dynamic, even mercurial nature of “real human” status that makes this mystery of our psychology so fascinating.

“We don’t humiliate vermin,” Adam Gopnik has observed, “or put them through show trials, or make them watch their fellow-vermin die first.” Right: we do that to people. Because we readily see others as human, we need reminding that our enemies are supposedly different. Which often works, because we also readily see others as not human. Smith has explored the nature of those conceptual boxes “human” and “not human.” But what really needs explaining is the constant, restless travel that the mind makes between them.