Females avoid conflict. They are afraid of violence. The males, on the other hand, are less averse to strife. But once conflict breaks out, the males are much better at reconciling. In a study done in Finland, children who had quarreled were asked how much longer they intended to be angry at one another. The boys proudly said: "Oh, at least one or two days." The girls said "forever".

When someone brutally kills someone else, we call him "animalistic." But we consider ourselves "human" when we give to the poor.

The intuitive connection children feel with animals can be a tremendous source of joy. The unconditional love received from pets, and the lack of artifice in the relationship, contrast sharply with the much trickier dealings with members of their own species.

We would much rather blame nature for what we don't like in ourselves than credit it for what we do like.

As in a Russian doll, however, the outer layers always contain an inner core. Instead of evolution having replaced simpler forms of empathy with more advanced ones, the latter are merely elaborations on the former and remain dependent on them. This also means that empathy comes naturally to us. It is not something we only learn later in life, or that is culturally constructed.

Humans became easy prey when they moved from the forest to the savanna, which deprived them of the option of climbing trees to flee predators. This shift made it necessary for the men to actively protect the women and their babies. Only as a result of this protection were women able to give birth in shorter intervals, perhaps once every two or three years. This meant that they could produce offspring about twice as frequently as apes. I would be willing to bet that this rapid reproduction is one of the reasons why we dominate the world today, and not the apes.

Morality, after all, has nothing to do with selflessness. On the contrary, self-interest is precisely the basis of the categorical imperative.