The Better Angels of Our Nature: Why Vio - By Steven Pinker Page 0,399

comprehend each other’s reasoning. That assumption too is not logically necessary. One could imagine a Robinson Crusoe who reasons in solitude, or a Galactic Overlord who is untouchable by his subjects. But natural selection could not have manufactured a solitary reasoner, because evolution works on populations, and Homo sapiens in particular is not just a rational animal but a social and language-using one. As for the Overlord, uneasy lies the head that wears a crown. Even he, in principle, must worry about the possibility of a fall from power that would require him to deal with his erstwhile underlings.

As we saw at the end of chapter 4, the assumptions of self-interest and sociality combine with reason to lay out a morality in which nonviolence is a goal. Violence is a Prisoner’s Dilemma in which either side can profit by preying on the other, but both are better off if neither one tries, since mutual predation leaves each side bruised and bloodied if not dead. In the game theorist’s definition of the dilemma, the two sides are not allowed to talk, and even if they were, they would have no grounds for trusting each other. But in real life people can confer, and they can bind their promises with emotional, social, or legal guarantors. And as soon as one side tries to prevail on the other not to injure him, he has no choice but to commit himself not to injure the other side either. As soon as he says, “It’s bad for you to hurt me,” he’s committed to “It’s bad for me to hurt you,” since logic cannot tell the difference between “me” and “you.” (After all, their meaning switches with every turn in the conversation.) As the philosopher William Godwin put it, “What magic is there in the pronoun ‘my’ that should justify us in overturning the decisions of impartial truth?”221 Nor can reason distinguish between Mike and Dave, or Lisa and Amy, or any other set of individuals, because as far as logic is concerned, they’re just a bunch of x’s and y’s. So as soon as you try to persuade someone to avoid harming you by appealing to reasons why he shouldn’t, you’re sucked into a commitment to the avoidance of harm as a general goal. And to the extent that you pride yourself on the quality of your reason, work to apply it far and wide, and use it to persuade others, you will be forced to deploy that reason in pursuit of universal interests, including an avoidance of violence.222

Humans, of course, were not created in a state of Original Reason. We descended from apes, spent hundreds of millennia in small bands, and evolved our cognitive processes in the service of hunting, gathering, and socializing. Only gradually, with the appearance of literacy, cities, and long-distance travel and communication, could our ancestors cultivate the faculty of reason and apply it to a broader range of concerns, a process that is still ongoing. One would expect that as collective rationality is honed over the ages, it will progressively whittle away at the shortsighted and hot-blooded impulses toward violence, and force us to treat a greater number of rational agents as we would have them treat us.

Our cognitive faculties need not have evolved to go in this direction. But once you have an open-ended reasoning system, even if it evolved for mundane problems like preparing food and securing alliances, you can’t keep it from entertaining propositions that are consequences of other propositions. When you acquired your mother tongue and came to understand This is the cat that killed the rat, nothing could prevent you from understanding This is the rat that ate the malt. When you learned how to add 37 + 24, nothing could prevent you from deriving the sum of 32 + 47. Cognitive scientists call this feat systematicity and attribute it to the combinatorial power of the neural systems that underlie language and reasoning.223 So if the members of species have the power to reason with one another, and enough opportunities to exercise that power, sooner or later they will stumble upon the mutual benefits of nonviolence and other forms of reciprocal consideration, and apply them more and more broadly.

This is the theory of the expanding circle as Peter Singer originally formulated it.224 Though I have co-opted his metaphor as a name for the historical process in which increased opportunities for perspective-taking led to sympathy for more diverse groups of people, Singer himself did not