After the news of the Paris shootings and bombings, I was wondering how I could explain terrorism to the Amazonian people, the Pirahãs, with whom I spent a great deal of my life. At first I thought I would not be able to explain such a thing. Then I remembered acts of terrorism that these people had suffered in their history, where men calling themselves “traders” raped and murdered women of the village. That much could be recounted. Sadly, all cultures have suffered. So I could tell the people that many such men arrived and killed many women, children, and other men. But then I realized that the Pirahãs would ask the question I was unable to answer, “Why?” They would never do this. Why do others do it?

Culture is that abstract network of values, structured knowledge, and social roles that shapes the dark matter of our minds, as we accumulate apperceptions and unify those by the unspoken narrative of our episodic memory. In other words, we become who we are by the confluence of individual experience and cultural interpretation of that experience. We talk to those with whom we believe we share values and experiences in order to bring sense to and give direction to ourselves as we navigate through the difficult world that has nurtured our genus since it emerged from the plains of Africa more than two million years ago.

Social media helps in this sense. In the past couple of days I have seen many attempts to answer the question — “Why did these men kill those people?” It is only natural that we, children of the Enlightenment, itself partially a gift of Paris, should try to answer this question. And over the coming weeks and months the governments of the western world will try to answer this question, as well as “How were they able to do this?” “What is our proper response?” “What aspect of world politics is most responsible for the cultivation of terrorism?” And so on.

Indeed, there are many lessons to draw from the tragedy in France. For example, do we get more upset when white Christians are murdered than brown Muslims? Shouldn’t we feel compassion for all who suffer, not merely those who look like us? It is right and proper that we should think about the complex issues surrounding terror. And I do think about these things.

But not today.

Terrorist acts are, till yet, trivial events. 9/11 caused the death rate in the United States that year to tick up by 1/10 of one percent. Paris on Friday will raise the rate in that country 2/100 of one percent. These are cold numbers to recite, and doing so just now probably repels most readers.

But we should not ignore them. A few million years after the first hominids began to explore their remarkable abilities, we have built societies incapable of looking away from carnage, even when the whole purpose of the carnage is to make us look and to cringe. The multiplier effect for what these few killers have done is provided by...us.  

In a world of spectacles and science and ordinary human existence, what we pay attention to defines our experience. My spouse merits my attention, attends to me in return, and that is love. Terrorist acts and internet clickbait and vulgar politicians and telemarketers all profit when I pay attention to them instead. Why should I? Should we not school ourselves to attend to diseases, not symptoms?

Paris, and we, could all use Camus at this point, in the famous conclusion to his 1951 L'Homme Révolté (The Rebel):  

At this meridian of thought, the rebel thus rejects divinity in order to share in the struggles and destiny of all men. We shall choose Ithaca, the faithful land, frugal and audacious thought, lucid action, and the generosity of the man who understands. In the light, the earth remains our first and our last love. Our brothers are breathing under the same sky as we; justice is a living thing. Now is born that strange joy which helps one live and die, and which we shall never again postpone to a later time. On the sorrowing earth it is the unresting thorn, the bitter brew, the harsh wind off the sea, the old and the new dawn. With this joy, through long struggle, we shall remake the soul of our time, and a Europe which will exclude nothing. Not even that phantom Nietzsche, who for twelve years after his downfall was continually invoked by the West as the blasted image of its loftiest knowledge and nihilism; nor the prophet of justice without mercy who lies, by mistake, in the unbelievers' plot at Highgate Cemetery; nor the deified mummy of the man of action in his glass coffin; nor any part of what intelligence and energy of Europe have ceaselessly furnished to the pride of a contemptible period. All may indeed live again, side by side with the martyrs of 1905, but on condition that it is understood that they correct one another, and that a limit, under the sun, shall curb them all. Each tells the other that he is not God; this is the end of romanticism. At this moment, when each of us must fit an arrow to his bow and enter the lists anew, to reconquer, within history and in spite of it, that which he owns already, the thin yield of his fields, the brief love of this earth, at this moment when at last a man is born, it is time to forsake our age and its adolescent furies. The bow bends; the wood complains. At the moment of supreme tension, there will leap into flight an unswerving arrow, a shaft that is inflexible and free.

McEwan's words are powerful and a good start to a difficult conversation that indeed requires "deep, serious thinking and ideas based on empirical evidence", as Brockman rightly points out. This is too difficult a problem to solve with one magic hit but we can at least try to benefit from empirical evidence. Let's go back to 9/11/01 and ask which aspects of our response made the world better or even simply safer? I am not yet advocating any particular point of view but before deciding what to do next we can at least ask any hypothetical—from what if we had done nothing to what if we did any specific subset of our actions? Though it's hard to imagine a good response, we can at least learn from past mistakes.

How are we to understand minds that take joy in slaughtering the innocent? To oversimply stupefyingly, our minds evolved to operate in one of three modes: with cooperative rationality, predatory rationality, or subordinate rationality. These modes were tailored by selection to identify best bet behaviors given one’s social ecology and individual situation. Each mode equips us with goals, appetites, and strategic sensibilities appropriate to its corresponding situation; each makes particular interpretations of others' intentions (cooperative, malign) self-evident; each makes consonant cultural elements appealing. To one mode, the Falangist cry "¡Viva la Muerte!" sounds repulsive; to another exalting. To one mode, slaughtering people is horrifying; to another, a triumph. Most importantly, we do not intuitively see the modern world as it is, but instead in terms of simplifying interpretations supplied by these modes of rationality, forged in a small-scale social world.

Over evolution, humans have greatly expanded the range and importance of positive-sum, win-win interactions so that we evolved a cooperative rationality as a basic part of our nature. Because win-win interactions are highly productive, and fighting is self-defeating among the equally powerful, cultures of cooperative rationality can emerge. The core orientation is positive-sum; the default setting is to put some weight on others, and the expectation is that others will prefer to cooperate. (Of course, we are notoriously capable of being cooperative at home, and predatory with outgroups.)

However, aggression as exploitation of the weak by the strong has been with animals almost since multicellularity, and so our minds come equipped with a predatory rationality: If the individual or group is stronger, and the social ecology does not suppress it, then minds activate this mode. This rationality is self and group supremacist; is attracted to war and power; focuses on subordinating others; places little weight on others, or even revels in inflicting suffering as a display of power. History is full of predatory rationalists, most recently Young Turk supremacists, National Socialist German supremacists, white supremacists, fascists, Japanese militarists, Communist supremacists, and lately Islamist supremacists. The core world-view is zero-sum, and the goal is to win power over others and the benefits that go with it. As cooperators, we see Hitler or Stalin or Saddam Hussein as “insane”; we see terrorists’ violence as “senseless,”— rather than seeing them as operating rationally but in a different mode with different values.

The third mode is subordinate rationality, activated by nonconscious recognition that if there were fighting, the adversary (the predator) would win. This rationality makes decisions according to an evolved logic of managing one’s subordination so it is less bad—predators are to be deferred to, excused, propitiated, identified with and above all not provoked.

The Enlightenment, human rights, markets, the printing press, science, the dismantling of force-based privilege—all led to cultural regions of relative internal peace and remarkable prosperity. Born into a world that has been internally pacified for so long, it is easy (and convenient) to mistake this for the state of nature, and not something maintained by the costly self-sacrifice of some. People raised in cultures that are predominantly organized around cooperative rationality cannot imagine any other rationality: So when people use violence it must be that they are driven to it by desperation or searing injustice, and they will stop when given justice. No one, we think, could possibly prefer war. (They must be poor, because why would a wealthy, well-educated Muslim doctor or engineer or billionaire fight?) A cooperator wants to arrive at a win-win covenant among equals. But predators envision instead an I-win-you-lose domination.

Another side-effect of an enduringly cooperative society is a loss of confidence in the efficacy of defense. Humans are designed to cultivate costly aggressive skills to the extent it would pay off in their world; cooperative environments incline us to invest instead in positive-sum skills. It follows that when cooperators are challenged by serious predatory threats, we implicitly assess ourselves as weak, and move into a subordinate rationality: Don’t provoke them! It is our fault! We intuitively feel that if we conciliate, threats will disappear. In contrast, predatory rationalists see concessions like the Sudetenland or Crimea or withdrawal from Gaza as evidence that extortion is working, and should be intensified. 

It is immensely difficult to understand our world of billions, with millions of fractally overlapping identities, and new media rapidly shifting rationalities. In such a world, knowing what to do is hard: Retaliation can turn nonbelligerents into enemies, yet a failure to respond also intoxicates predators. Still, to have a scientific understanding of the complex anthropology of modernization, it will not do to simply view others through the lens of our own cooperative and subordinate rationalities—our hopes and our fears.