Why We Kill Each Other: The Evolution of War

In order to understand why we kill each other, the concept of war must be approached from an objective perspective. It is too simplistic and uninformative to qualitatively state that all war is bad or that all war is good. The role of the scientist is not to inform us whether a war (or war in general) is morally right or wrong. It is, however, the scientist’s role to help explain why we kill each other. What function does it serve? What triggers it? Scientists and specifically anthropologists, biologists, and psychologists, who study human beings, have a great responsibility when it comes to explaining war.

Last year, Steven Pinker gave a lecture on violence. He explained that years of data suggest that the prevalence of violence is lessening. Even though that may be the case, he indicates that this finding should encourage us to be complacent. War is still a problem that could threaten the survival of our species. Pinker suggests that we approach the question of war differently. We should not be asking why we go to war. We should be asking why we are becoming more peaceful. The answer to this question may provide us with a solution to the problem of war.

My perspective is that we need to be asking both questions. We need to know why we fight. What function does it serve? On the other hand, we also need to be asking the question: “What makes us peaceful?”

In David Livingstone Smith’s book, The Most Dangerous Animal, Smith approaches the problem of war from both angles. Early theories of human nature have insinuated either that human beings were innately good or inherently evil. Like the nature vs. nurture theory that we were taught in college, this is a false dichotomy. Humans are neither good nor evil. There are times when we do dastardly things and there are times when we are altruistic. The idea of the noble savage is a myth as is the idea that primitive humans were barbarous murders (although you are far more likely to be murdered in a hunter-gatherer society than you are in an agrarian culture).

David Livingstone Smith provides vivid anthropological evidence of war in our ancestral past. He also elucidates a similar phenomenon, raiding, in our closest living relatives, the chimpanzee.

One of the reasons that people do not like to approach topics such as war from an evolutionary perspective is because they falsely assume that it moralizes issue. They believe that providing an evolutionary explanation for war somehow justifies it. This is simply not true. It is known as the naturalistic fallacy, the belief that whatever occurs in nature is good.

Additionally, people dislike the evolutionary approach to war because they think that it relieves people of responsibility. If there is a biological explanation for something, it is impossible to hold someone responsible for it. Fear of biological determinism is not a sufficient excuse for understanding the evolutionary biomechanics of war.

These people who are worried about evolutionary explanations of human behavior are also afraid that such explanations may brand behaviors as incurable. This is also simply untrue. For example, consider nearsightedness or myopia. Myopia is a biological problem, which can be cured by corrective lenses or lasik eye surgery. The only way that we can correct the problem of war is if we can understand truth about why we fight.

So why do we fight? David Livingstone Smith did an excellent job of providing evidence for our evolutionary and biological penchant for war and provided some insight into why we fight. However, you still come away from the book unsatisfied with our current understanding of war. Smith’s greatest success was getting the dialogue of an evolutionary understanding of war started. To my knowledge, his is the first book written on the topic.

There is no satisfying answer to the question of why we go to war. But there are several interesting insights. Humans are equipped with a sense of kinship. We love the people who share our genes, whether we like it or not. Our sense of kinship does not stop at genetic relatedness. We also have a sense of kinship with the groups that we affiliate with and we will do anything to protect them. Our kinship is often exploited by nations and religions, not surprisingly the two institutions that are responsible for most, if not all, wars. The short and unsatisfying answer of why we fight is because it feels good. We become enthused zealots who want to destroy the evil that threatens our groups.

What stops us from killing? Fortunately, we have evolved a mechanism that also prevents us from killing. This is something we can be optimistic about. Most humans are endowed with a sense of disgust. When we see pictures of mutilated human bodies, we are appalled. Our sense of disgust with the murder of our fellow humans is so strong that most people who have killed other human beings are haunted by the memory and suffer from post-traumatic stress disorder.

David Livingstone Smith provides an excellent survey of war from an evolutionary perspective. His book is full of all sorts of insights that help explain why we fight and why we don’t. I recommend The Most Dangerous Animal to anybody who is seriously interested in understanding the mechanics of why we go to war.