"If men had been overwhelmingly benevolent, if each had aimed only at the happiness of all, if everyone had loved his neighbour as himself, there would. have been no need for the rules that constitute justice. Nor would there have been any need for them if nature had supplied abundantly, and without any effort on our part, all that we could want, if food and warmth had been as inexhaustibly available as, until recently, air and water seemed to be."