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.

Exclusive homosexuality is not very common in nature.

When it comes to social interaction, the chimpanzees appear to be just as intelligent as we are.

People want to work with somebody who feels shame, who worries about the perceptions of others. Dishonesty is something we don't like in others.

Future benefits rarely figure in the minds of animals.

The development of family entities enables men to cooperate far more effectively. Instead of constantly competing for the women with other men, each man essentially has a partner assigned to him, one with whom he can establish a family.

We are territorial, power-hungry and even more brutal than chimpanzees.