ESPECIALLY in the aftermath of a gruesome incident like the Mamasapano clash, people may tend to find it easy to buy into an aggressive line, like a pitch for an all-out war. Warmongers are more likely to sell their deadly ware because events have predisposed more people to heeding combative calls.

The scenario may look contentious, but not unlikely. It may prove more likely if you believe the assumption, offered by Harvard biologist Edward O. Wilson, that aggression is innate among human beings. Or, we have a marked hereditary predisposition to aggressive behavior, and given the right excuse, it will show itself up. And precisely on such account do we say that crimson is the color of history. Man has never run short of the right excuse to gear for and go to war.

“Any excuse for real war will do,” writes Mr. Wilson in The Social Conquest of the Earth, “so long as it is seen as necessary to protect the tribe.” If no other excuse is conveniently available, “there has always been God.” All wars are irrational and they come with their own horrors, but these hardly find a place in the collective memory, or if they do “they make a fascination” to let you expect another encounter.

I suspect a similarity in the behavior of a civilian in an organized crowd occupying the streets with that of a warrior in a group engaged in a firefight — reason yields to instinct and passion; deliberation and prudence to spontaneity, ferocity, and aggression; egoism to altruism. Except for one deadly difference, the warrior is armed.

On the early morning of January 25, 2015, a unit of the Special Action Force (SAF) of the Philippine National Police found itself trading fire with an armed unit of the Moro Islamic Liberation Front (MILF), incurring heavy casualties as morning drew on. Despite frenzied efforts by both government and MILF panels of the Coordinating Committee on the Cessation of Hostilities for the two sides to cease firing, the shooting came to a complete stop only at about 2:00 PM of the same day. The crowd mind has its own dynamics that won’t switch off on cue.

Subsequent cleaning-up operations by MILF fighters saw them gathering the spoils of battle — guns, cellphones, vests, uniform, etc., and reportedly shooting at SAF policemen whom they found wounded but alive. A video footage of the scene uploaded for YouTube viewing recorded voices of men, apparently elated, talking in triumphant glee, while the camera was panning over the dead SAFs. It’s utterly depressing.

It has the character of a syndrome for which the American sociologist Randall Collins has coined the phrase “forward panic.” For sure it wasn’t invented in Mamasapano. Mr. Collins writes that the syndrome is common in warfare. The tendency for troops to kill enemy soldiers who are trying to surrender was well documented for trench warfare in World War I. The pattern was also documented widely in World War II. For being what it is, guerrilla war gives rise to conditions that make forward panic frequent, as documented in the Vietnam War.

This is war bringing out the beast in men. The paradox is it also brings out the best. There is gore in war, but there is glory at the same time. Gen. George S. Patton, Jr., the American war hero, is known for his quips that acknowledge this truth about the human condition, such as this one: “I want you to remember, that no poor dumb bastard ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country.” And this one: “May God have mercy for my enemies because I won’t.”

The paradox comes with our being human, as Mr. Wilson argues: “The worst in our nature coexists with the best, and so will it ever be. To scrub it out, if such were possible, would make us less than human.” Blame it not on the biblical Fall. The “human condition is an endemic turmoil rooted in the evolution processes that created us.” The governing law of these processes is Charles Darwin’s theory of natural selection, as later elaborated by modern biology and has given rise to the idea of unit or level of selection.

At the individual (standard) level, the selfish is the fittest, enjoying differential reproductive success. Human goodness beyond kin comes unnaturally (say, man defying his selfish nature through cultural “memes”). The individual is the only level recognized by the likes of the aggressive atheist Richard Dawkins. Mr. Wilson and company, apart from acknowledging the individual, introduce the idea of selection at group level, which assumes group-vs.-group competition, hence allowing for the better angel of our nature, altruism. As a predominant group trait, altruism confers an advantage for selection in the struggle among groups. Hence, every human is a composite of hereditable traits representing the dark angel and the better angel of our nature.

Group creation is held to be a unique achievement of humans, to which we owe the enhancement of our social intelligence and thus our collective status as the sapient one. We are innately groupish, thanks to group selection. The trade-off, Mr. Wilson says, is that our brain developed the hardwire propensity to downgrade other-group members. “Our bloody nature,” he concludes, “is ingrained because group-versus-group was a principal driving force that made us what we are.”

What does this hold for the likes of Mamasapano? That’s a hugely difficult question for what may pass as my puny intellect. All I know is that an innate propensity, bringing a potential challenge, may find a better match in another instinct possessed by humans. There is, in fact, one that’s unique to us — language.

Don’t shoot. Talk.

Mario M. Galang is a senior fellow of Action for Economic Reforms and a development and governance specialist.