When it comes to explaining human thought and behavior, the possibility that heredity plays any role at all still has the power to shock. To acknowledge human nature, many think, is to endorse racism, sexism, war, greed, genocide, nihilism, reactionary politics, and neglect of children and the disadvantaged. Any claim that the mind has an innate organization strikes people not as a hypothesis that might be incorrect but as a thought it is immoral to think.

Most wars are not fought over shortages of resources such as food and water, but rather over conquest, revenge, and ideology.

The strongest argument against totalitarianism may be a recognition of a universal human nature; that all humans have innate desires for life, liberty and the pursuit of happiness. The doctrine of the blank slate... is a totalitarian's dream.

Sex and excretion are reminders that anyone's claim to round-the-clock dignity is tenuous. The so-called rational animal has a desperate drive to pair up and moan and writhe.

My laptop has freed me to travel.

What is true for the emotions may also be true for the intellect. Some of our perplexities may come from a mismatch between the purposes for which our cognitive faculties evolved and the purposes to which we put them today.

Reason is non-negotiable. Try to argue against it, or to exclude it from some realm of knowledge, and you've already lost the argument, because you're using reason to make your case. ... We don't "believe" in reason.