We start out postulating sharp boundaries, such as between humans and apes, or between apes and monkeys, but are in fact dealing with sand castles that lose much of their structure when the sea of knowledge washes over them. They turn into hills, leveled ever more, until we are back to where evolutionary theory always leads us: a gently sloping beach.

The primate laugh is given in playful contexts, and as such has a strong similarity to the human laugh.

Most men probably wouldn't want to live the lives of bonobos. They're constantly clinging to their mothers' apron strings. They lack the ability to make decisions about their own fates, something that we and male chimpanzees practically consider our birthright.

Personally, I think it is possible to build a society that is moral on a nonreligious basis, but the jury is still out on that.

The more self-aware an animal is, the more empathetic it tends to be.

The sturdiest pillars of human morality are compassion and a sense of justice.

If you want to design a successful human society you need to know what kind of animal we are. Are we a social animal or a selfish animal? Do we respond better when we're solitary or living in a group?