We are naturally moral beings, but our environments can enhance - or, sadly, degrade - this innate moral sense.

A growing body of evidence suggests that humans do have a rudimentary moral sense from the very start of life.

Humans are social beings, and we are happier, and better, when connected to others.

Technology is unlocking the innate compassion we have for our fellow human beings.

Natural selection shaped the human brain to be drawn toward aspects of nature that enhance our survival and reproduction, like verdant landscapes and docile creatures. There is no payoff to getting the warm fuzzies in the presence of rats, snakes, mosquitoes, cockroaches, herpes simplex and the rabies virus.

If our moral attitudes are entirely the result of nonrational factors, such as gut feelings and the absorption of cultural norms, they should either be stable or randomly drift over time, like skirt lengths or the widths of ties. They shouldn't show systematic change over human history. But they do.