The theory that religion is a force for peace, often heard among the religious right and its allies today, does not fit the facts of history.

I think that communism was a major force for violence for more than 100 years, because it was built into its ideology - that progress comes through class struggle, often violent.

The last 100 years of research into the human brain...sees the brain as an organ that works by physical principles just like the other organs in the body...our emotions and higher callings, such as religion, as well as our grubby low-level physical systems like stereo vision and motor control, are products of a machine.

No one knows what the nongenetic causes of individuality are. Perhaps people are shaped by modifications of genes that take place after conception, or by haphazard fluctuations in the chemical soup in the womb or the wiring up of the brain or the expression of the genes themselves.

As long as your ideology identifies the main source of the world's ills as a definable group, it opens the world up to genocide.

Dominance in an adaptation to anarchy and it serves no purpose in a society that has undergone a civilising process or in an international system regulated by agreements and norms. Anything that deflates the concept of dominance is likely to drive down the frequency of fights between individuals and wars.

Societies that empower women are less violent in every way.