“Warfare is ultimately not a denial of the human capacity for cooperation, but merely the most destructive expression of it.”
The roots of human cooperation may lie in human aggression. We are selfish by nature, yet also follow rules requiring us to be nice to others.
“That’s why we have moral dilemmas,” Dr. Tomasello said, “because we are both selfish and altruistic at the same time.”
"We May Be Born With an Urge to Help"
- Some Biologists Find an Urge in Human Nature to Help - NYTimes.com (view on Google Sidewiki)