If my starting offer is “I get to rob, beat, enslave, and kill you and your kind, but you don’t get to rob, beat, enslave, or kill me or my kind,” I can’t expect you to agree to the deal or third parties to ratify it, because there’s no good reason that I should get privileges just because I’m me and you’re not. Nor are we likely to agree to the deal “I get to rob, beat, enslave, and ill you and your kind, and you get to rob, beat, enslave, and kill me and my kind,” despite its symmetry, because the advantages either of us might get in harming the other are massively outweighed by the disadvantages we would suffer in being harmed.

Steven Pinker, Enlightenment now: the case for reason, science, humanism, and progress, New York, 2018, p. 28