Man's life in a state of nature, said Thomas Hobbes in Leviathan, is a "war of all against all:"
And in that state of nature, no arts; no letters; no society; and which is worst of all, continual fear and danger of violent death; and the life of man, solitary, poor, nasty, brutish, and short.
In the Hobbesian view, there can ultimately be no cure for violence; it is in our wiring; in fact, it is in the bones of the universe in which we live. You can counteract or punish it--you can shoot the shooters--but it will always be with you. Civilization, according to Hobbes, is the way we organize ourselves to repress violence.
Contrast the views of Zygmunt Bauman, who in Modernity and the Holocaust wrote that in the state of nature we feel an "animal pity" that prevents violence, and that civilization is the way we organize ourselves to kill ever larger numbers of people. In Bauman's view, the Nazi bureaucracy of the Final Solution was a perfectly ordinary bureaucracy with extraordinary goals; the vocabulary ("cargo" instead of "Jews" in one memo he cites), the diffusion of responsibility across an organization, and the distance from the victim are all artifacts of "civilized" efficiency that permitted mass killing. The Nazis had previously attempted to shoot the Jews, but these massacres had psychologically overwhelmed the ordinary men of the shooting brigades, who had to look their victims in the eye and watch them suffer.
The sociobiologists agree with Bauman, not Hobbes. In On Aggression, Konrad Lorenz observes that in nature, aggressive animals have quite complicated rituals worked out to avoid hurting each other. Wolves, which have an intensely close and cooperative social structure, almost never hurt other wolves. Male deer, which lock antlers in a supremacy ritual, only thrust at each other's antlers, and never pierce each other's unprotected flank. Lorenz surmises that implementing protections against intraspecies violence was a crucial evolutionary step for any animal that had built-in weapons (fangs, antlers, claws) strong enough to do serious harm. Because man had no such weapons, we never evolved defenses against violence as strong as these other creatures did.
Which is not to say that man, in a state of nature, is as violent as Hobbes thought. Lorenz tells stories of various primitive tribes: Pacific Islanders who remove the feathers from their arrows when they go to war, so it is hard to shoot straight; headhunters who only prey on marginal members of the other tribe, and so forth. Though he never uses the phrase, Lorenz agrees that Bauman's "animal pity" exists: we have a built-in defense against hurting a member of our own species, which we have only succeeded in overcoming through modern social organization and technology.
At some point, our physical evolution stopped, and our mental evolution began (in Richard Dawkin's view, the point at which "memes" replaced genes as the basic replicator.) Since ideas and their implementations can go through many generations in just a few years, this evolution-like process lacks the safeguards of physical evolution, where the mass of time which change takes allows the near-simultaneous implementation of weapons and defenses against using them. While a wolf has a built-in resistance against using its teeth or claws against a member of its own species, we have no biological awareness of nuclear weapons, which, after all, have existed for only five decades. So the "animal pity", which is based on proximity and an awareness of the victim's suffering, is easily overcome by a "civilized" organization which places the victim at an immense distance and diffuses the responsibility for his destruction across as many people as possible.
Lt. Col. Dave Grossman, in his excellent book On Killing, starts from Bauman's and Lorenz's premise, that humans have an innate resistance to killing other humans. He presents S.L.A. Marshall's famous research indicating that only 15-20% of American soldiers in World War II--the most popular war of this century--ever fired their weapons at the enemy, while the rest fired in the air or occupied themselves with other tasks, including loading weapons for others, reconaissance, etc. According to Grossman, there is significant circumstantial evidence from earlier wars to support this thesis; for example, on the battlefield after Antietam, numerous loaded muskets were found, many with multiple charges crammed down the barrel (one had been loaded 23 times and never fired.) This indicated that the soldiers were making a show for their officers of loading but were only pretending to fire their weapons at the enemy.
Grossman constructs a model of the circumstances under which humans will kill other humans. In order to overcome our resistance to killing, the following circumstances (all of them hallmarks of "civilized" organization) must exist:
Grossman also presents the disparity of psychological effects based on distance. Post traumatic stress disorder--from which as many as 1.4 million Vietnam vets suffer--is prevalent in people who killed in hand to hand combat or across short distances. Many military studies have demonstrated that people who fly bombing missions or fight from ships are not similarly affected; they never make eye contact with the victim, and in fact, do not see the results of their acts at all, except perhaps as an abstract and distant light show.
Grossman must be right about this, or we wouldn't have strayed across the line into mass bombing of civilian populations at all. If you think about it, there is no moral distinction to be drawn between rounding up the entire citizenry of Dresden and shooting them, and dropping bombs that create a firestorm killing 70,000 people. The fact that we were quite comfortable doing the latter, but would never entertain the idea of the former, is not based on any moral difference but entirely on distance and abstraction.
Again, it is civilization, and the technology we have organized ourselves to produce, that enables us to kill millions half-way around the globe at the push of a button. This is the ultimate proof that Hobbes was wrong--civilization is the way we organize ourselves to commit mass violence, not the way we organize ourselves to contain it.
If we live in a violent world today, it is because life is out of balance, because our "animal pity" has not learned to cross the same distance that our missiles can.