We are all members of the same flawed species. Putting our moral vision into practice means imposing our will on others. The human lust for power and esteem, coupled with its vulnerability to self-deception and self-righteousness, makes that an invitation to a calamity, all the worse when the power is directed at a goal as quixotic as eradicating human self-interest.

Nature is a hanging judge," goes an old saying. Many tragedies come from our physical and cognitive makeup. Our bodies are extraordinarily improbable arrangements of matter, with many ways for things to go wrong and only a few ways for things to go right. We are certain to die, and smart enough to know it. Our minds are adapted to a world that no longer exists, prone to misunderstandings correctable only by arduous education, and condemned to perplexity about the deepest questions we can ascertain.

Equality is not the empirical claim that all groups of humans are interchangeable; it is the moral principle that individuals should not be judged or constrained by the average properties of their group.

There is no society ever discovered in the remotest corner of the world that has not had something that we would consider the arts. Visual arts - decoration of surfaces and bodies - appears to be a human universal.

Academics lack perspective. In a debate on whether the world is round, they would argue, 'No,' because it's an oblate spheroid. They suffer from 'the curse of knowledge': the inability to imagine what it's like not to know something that they know.

Of course genes can’t pull the levers of our behavior directly. But they affect the wiring and workings of the brain, and the brain is the seat of our drives, temperaments and patterns of thought. Each of us is dealt a unique hand of tastes and aptitudes, like curiosity, ambition, empathy, a thirst for novelty or for security, a comfort level with the social or the mechanical or the abstract. Some opportunities we come across click with our constitutions and set us along a path in life.

I teach classes 28 weeks of the year, but the rest of the time I do research and write books.