We human beings have a remarkable ability to dehumanize one another: to conceive of others as subhuman creatures, and to treat them accordingly.
I argue in my book Less Than Human: Why We Demean, Enslave, and Exterminate Others (St. Martin's Press, 2011) that there are two powerful psychological forces that fuel the dehumanizing impulse. One is psychological essentialism. Psychological essentialism is the tendency to think that every kind of living thing possesses a unique essence: a mysterious inner quality that makes it a member of that kind. Consider dogs. Dogs come in an enormous range of shapes, colors, and sizes. However, we are inclined to think that they all share a common canine essence, the possession of which makes them all dogs. Similarly, we imagine that we human beings are endowed with a special human essence (a human "soul," if you will), and that it's this that makes us human.
One important feature of essentialist thinking is the notion that the essence of a thing is distinct from its appearance. Put simply, things can seem to be something other than what they really are. This principle is crucial for understanding dehumanization, because it implies that someone can appear to be human appearance but lack a human essence. Think of them as counterfeit human beings.
Scientifically speaking, this is nonsense. There's no such thing as a canine essence or a human essence. Nevertheless, the essentialist mindset is deeply entrenched in the human psyche and powerfully influences the ways that we make sense of the world
The second psychological dynamic behind dehumanization is the belief that nature is arranged as a hierarchy. In earlier centuries, this was known as the Great Chain of Being. God, the most perfect being, was assigned to the topmost position in the cosmic pecking order, and inert matter was thought to lie at the bottom, with every living creature situated at some intermediate position. We humans (modest beings that we are) have always placed ourselves near the uppermost rank, and have supposed that every other creature is less than human.
Even though the notion of the Great Chain of Being is radically at odds with our scientific picture of the cosmos, it maintains an iron grip on the human imagination. It is very difficult for us not to conceive of the world in terms of dichotomies like "higher" and "lower," "human," and "subhuman."
These two factors—essentialism and the belief in a cosmic hierarchy—work in tandem when people dehumanize one another. The dehumanized person is imagined as a human-looking creature with a subhuman essence. They are inferior animals misleadingly dressed up as human beings. This is how European colonists conceived of Native Americans, and how slave owners conceived of their human chattel. This is how the Nazis conceived of Jews, and how Rwandan Hutus conceived of their Tutsi neighbors. This way of thinking is reflected in dehumanizing epithets-referring to whole populations as lice, flies, rats, bacilli, dogs, wolves, monsters, and so on.
Dehumanization has the function of decommissioning our moral sentiments. In dehumanizing others, we exclude them from the circle of moral obligation. We can then kill, oppress, and enslave them with impunity. Taking the life of a dehumanized person becomes of no greater consequence than crushing an insect under one's boot. Here is a case in point. Right now, as you read these words, genocidal violence is gathering momentum in Sudan. The government of Omar Hassan Ahmad Al-Bashir, a man who has been charged by the International Criminal Court with war crimes, crimes against humanity, and genocide, is ethnically cleansing Sudan of its marginalized people. The violence is not restricted to Darfur, where between two and four hundred thousand people have already been murdered. It has spread to Abyei, the Blue Nile State, the Nuba mountains, and possibly elsewhere. It's clear from the rhetoric of the Janjaweed militias that dehumanization lubricates the machinery of slaughter in Sudan.
"Dog, son of dogs, we came to kill you and your kids."
"Kill the black donkeys! Kill the black dogs! Kill the black monkeys!"
"You blacks are not human. We can do anything we want to you."
"We kill our cows when they have black calves. We will kill you too."
"You make this area dirty; we are here to clean the area."
"You blacks are like monkeys. You are not human."
There is no disputing the fact that dehumanization and atrocity often go hand in hand. But what about indifference to atrocity? Might not dehumanization be implicated in this as well? The philosopher Richard Rorty thought so. In a paper written in 1992, when Serbian forces were engaged in the ethnic cleansing of Bosnia, Rorty argued that those of us who are safely cocooned in affluent Western democracies tend to dehumanize both the perpetrators and the victims of genocide. "We think of Serbs or Nazis as animals," he observed, "because ravenous beasts of prey are animals. We think of Muslims or Jews being herded into concentration camps as animals, because cattle are animals. Neither sort of animal is very much like us, and there seems to be no point in human beings being involved in quarrels between animals."
It is easy to recognize and condemn blatant dehumanization perpetrated by Janjaweed genocidaires. It is more difficult to interrogate our own indifference. Although this sort of self-examination can be deeply unsettling, there is compensation to be gained in a life that is more completely in accord with one's moral convictions, and the satisfaction of adding one more voice to the growing chorus of those who refuse to turn their backs on the people of Sudan.