Violent movements attract thugs and firebrands who enjoy the mayhem. Violent tactics provide a pretext for retaliation by the enemy and alienate third parties who might otherwise support the movement.

I have never been a fan of science fiction. For me, fiction has to explore the combinatorial possibilities of people interacting under the constraints imposed by our biology and history. When an author is free to suspend the constraints, it's tennis without a net.

Cognitive psychology tells us that the unaided human mind is vulnerable to many fallacies and illusions because of its reliance on its memory for vivid anecdotes rather than systematic statistics.

The human moral sense can excuse any atrocity in the minds of those who commit it, and it furnishes them with motives for acts of violence that bring them no tangible benefit.

We instinctively fear snakes, but we appear not to be afraid of fast cars, which are a real danger now. This suggests our emotions were shaped by our evolutionary environment not the one we grew up in.

The connections I draw between human nature and political systems in my new book, for example, were prefigured in the debates during the Enlightenment and during the framing of the American Constitution.

The moral, then, is that familiar categories of behavior - marriage customs, food taboos, folk superstitions, and so on - certainly do vary across cultures and have to be learned, but the deeper mechanisms of mental computation that generate them may be universal and innate.