The basis of social relationships is reciprocity: if you cooperate with others, others will cooperate with you.

I came into history from a primary concern with mathematics and science. This has been a tremendous help to me as a person and as a historian, although it must be admitted it has served to make my historical interpretations less conventional than may be acceptable of many of my colleagues in the field.

To this day the Arab influence is evident in southern Italy, northern Africa and, above all, in Spain.

The process by which civilization, as an abstract entity distinct from the societies in which it is embodied, dies or is reborn is a very significant one.

The argument that the two parties should represent opposed ideals and policies, one, perhaps, of the Right and the other of the Left, is a foolish idea acceptable only to doctrinaire and academic thinkers. Instead, the two parties should be almost identical, so that the American people can throw the rascals out at any election without leading to any profound or extensive shifts in policy. Then it should be possible to replace it, every four years if necessary, by the other party, which will be none of these things but will still pursue, with new vigor, approximately the same basic policies.

The difference between a stable society and an unstable one is that the restraints in an unstable one are external. In a stable society government ultimately becomes unnecessary; the restraints on people's actions are internal, they're self-disciplined.

Each individual in a society is a nexus where innumerable relationships of this character intersect.