We are an extraordinarily social species. In fact, there’s no other mammal that comes anywhere near us in this regard. You might say that we possess an instinct for solidarity. Humans are this way because our very survival depends on being members of highly cooperative communities. It’s been our condition for hundreds of thousands if not millions of years, and this applies just as much to hunter-gatherer bands dwelling in the Amazonian rainforest as it does to the residents of the sprawling urban metropolises of the so-called developed world. Our social way of life demands that we be exquisitely attuned to one another, and this has a significant impact on how we manage violence.
Like other social animals, humans inhibit severe forms of violence against members of their own community. For nonhuman animals, the community is limited to the local breeding group—the troop, colony, or pack. These inhibitions are needed, because social life can’t possibly be sustained if the members of a group are at each other’s throats. But these inhibitions against violence don’t apply to strangers, who can be viciously attacked and literally torn to shreds without harming the social fabric.
Among nonhuman animals, the tendency to discriminate between insiders and outsiders, between “us” and “them,” is a more or less automatic, instinctive response. But things go differently for us. Like other social mammals, we automatically recoil from performing acts of lethal violence against those whom we recognize as being part of our community. But in our case, violence-avoidance isn’t automatically restricted to the local community. It extends to outsiders, to strangers, whom we cannot help but recognize as fellow human beings. This is a gut-level response to seeing others as human. It’s not something that we can turn on or off at will. It happens to us rather than being something that we choose to do.
Our aversion to harming one another is in tension with a basic condition of animal life. Animals must kill, damage, or exploit other organisms in order to live. This is obviously true of predators that consume the flesh of others, but it’s also true of parasites that drain their blood, and even gentle herbivores that kill and dismember plants. Human beings are no exception. We have a long history of killing other organisms.
It’s impossible to know exactly how long we’ve been killing and eating other animals. It’s very likely that some of our very early ancestors caught and ate small animals—insects, lizards, rodents, and the like—that were abundant, rich in protein, and easy to capture. They may have begun to eat the flesh of larger animals by scavenging kills made by large predators—mobbing and driving away the lions and hyenas with sticks and stones. This cooperative activity may have been a dress rehearsal for cooperative group hunting, which was well established over three million years ago. Whatever the details, it’s clear that the organized killing of other species is a crucial part of the human story and may well have contributed to the evolution of our massive brains by supplying the precious calories needed to support this very expensive organ. Hunting was just the beginning. Once humans had abandoned their foraging way of life they domesticated animals, keeping herds for meat and milk, exploiting their labor, and using their hides to manufacture leather. And it’s a straight line from there to the industrialized slaughter of modern factory farming.
The act of killing is monumentally important to human lives. The question of what kinds of beings are killable, and under what circumstances they may be killed, is perhaps the most basic of all moral questions. In all societies, it’s permissible to take only certain kinds of lives and forbidden to take others. In some cases, there are sacred animals whose lives are protected, but whether or not this is the case, human beings are granted a privileged moral status, and are treated quite differently than most nonhuman organisms. That’s not to say that killing humans is always forbidden. There are circumstances in which killing others is allowed or even mandatory (for example, in our own culture there’s abortion, capital punishment, and killing in combat).
The special moral status that we accord to human beings is, I believe, bound up with our inhibitions against doing violence to them. Unlike other animals, we’re driven to find reasons for our actions, and when we cannot find reasons we invent them. We then codify these reasons in systems of rules—rules that permit some actions and forbid others. So, we concoct justifications for why it’s morally acceptable to do violence to some kinds of beings but not others.
One such justification, found in indigenous hunting cultures, is to deny that killing animals is really an act of violence. Animals supposedly choose to make themselves available to hunters and do this because they want to be killed. Philosopher T. J. Kasperbauer points out that, from this perspective, “animals are seen as willful participants who supposedly gain as much from the hunt as the hunters.”1
This strange idea—which is backed by systems of belief about the supernatural realm—may have been widespread during our hunter-gatherer past. But it’s certain that at some point in time, a different, more robust solution to the problem of killing took root, and according to this framework, we are free to kill or exploit those living things that are ranked beneath the human. We can kill cockroaches and lobsters and sheep and cattle in human cultures—the idea of a natural hierarchy that I discussed in chapter eleven—because they are “lower” in the grand scheme of things than we are. This ideological framework also had another advantage. It freed us up to kill and oppress our fellow human beings. With the hierarchical scheme firmly in place, we could subvert our inhibitions against doing violence to other people by representing those people as less than human.
The idea of the Great Chain of Being was a great invention, and like many other great inventions, it probably did not spring up at any one place at any one time, but arose independently in various far-flung cultures. The Chain is now thoroughly entrenched in our way of thinking, and our way of life, because it offers a powerful solution to the problem of killing. We all have to kill to live. Even vegans take the lives of vegetables.
The idea that nature is arranged as a hierarchy, and that our lives matter more than the lives of organisms lower down the chain, is an illusion. But because killing is a necessary condition for human life, it’s an illusion that would be hard for us to do without. Because killing is mandatory for human survival, it’s tempting to fall into the trap of hierarchical thinking, and to rationalize this bias with fancy philosophical arguments or religious beliefs. But to resist dehumanization, it’s important to resist, and help others to resist, the fantasy that we are objectively “higher” than those plants and animals whose lives we take.