Old men are dangerous: it doesn't matter to them what is going to happen to the world.

Power does not corrupt men; fools, however, if they get into a position of power, corrupt power.

The nation's morals are like its teeth: the more decayed they are the more it hurts to touch them.

Discussing vaccination with a doctor is like discussing vegetarianism with a butcher.

The truth is, hardly any of us have ethical energy enough for more than one really inflexible point of honor.

It seems as though every time you learn something new you have to give up something.

Social progress takes effect through the replacement of all institutions by new ones; and since every institution involves the recognition of the duty of conforming to it, progress must involve the repudiation of an established duty at every step.