“legal investigation. As Clinton noted, “My goal in this deposition was to be truthful, but not particularly helpful.”

“Trivers, pursuing his theory of the emotions to its logical conclusion, notes that in a world of walking lie detectors the best strategy is to believe your own lies. You can’t leak your hidden intentions if you don’t think they are your intentions. According to his theory of self-deception, the conscious mind sometimes hides the truth from itself the better to hide it from others. But the truth is useful, so it should be registered somewhere in the mind, walled off from the parts that interact with other people.”

“Evolutionarily speaking, there is seldom any mystery in why we seek the goals we seek — why, for example, people would rather make love with an attractive partner than get a slap on the belly with a wet fish.”

“Morality, then, is not a set of arbitrary regulations dictated by a vengeful deity and written down in a book; nor is it the custom of a particular culture or tribe. It is a consequence of the interchangeability of perspectives and the opportunity the world provides for positive-sum games.”

“The more you think about and interact with other people, the more you realize that it is untenable to privilege your interests over theirs, at least not if you want them to listen to you. You can’t say that my interests are special compared to yours any more than you can say that the particular spot that I am standing on is a unique part of the universe because I happen to be standing on it that very minute.”

“Thinking is computation, I claim, but that does not mean that the computer is a good metaphor for the mind. The mind is a set of modules, but the modules are not encapsulated boxes or circumscribed swatches on the surface of the brain. The organization of our mental modules comes from our genetic program, but that does not mean that there is a gene for every trait or that learning is less important than we used to think. The mind is an adaptation designed by natural selection, but that does not mean that everything we think, feel, and do is biologically adaptive. We evolved from apes, but that does not mean we have the same minds as apes. And the ultimate goal of natural selection is to propagate genes, but that does not mean that the ultimate goal of people is to propagate genes.”

“I am sometimes asked, "How do you know there won't be a war tomorrow (or a genocide, or an act of terrorism) that will refute your whole thesis?" The question misses the point of this book. The point is not that we have entered an Age of Aquarius in which every last earthling has been pacified forever. It is that substantial reductions in violence have taken place, and it is important to understand them. Declines in violence are caused by political, economic, and ideological conditions that take hold in particular cultures at particular times. If the conditions reverse, violence could go right back up.”