Aggression or Cooperation

"We start with the biological observation that no individual could survive in a world of scarce resources without a strong measure of self-interest, one that includes at the very least his own family and close associates. That self-interest can manifest itself in one of two ways when dealing with strangers; through either aggression or cooperation."

Richard Epstein, "Coercion vs. Consent," Reason, Vol. 35, No. 10, pp. 40-50.