But as precedents survive like the clavicle in the cat, long after the use they once served is at an end, and the reason for them has been forgotten,… - Oliver Wendell Holmes

When men have realized that time has upset many fighting faiths, they may come to believe even more than they believe the very foundations of their own conduct that the ultimate good desired is better reached by free trade in ideas – that the best test of truth is the power of the thought to get itself accepted in the competition of the market, and that truth is the only ground upon which their wishes safely can be carried out. That, at any rate, is the theory of our Constitution. It is an experiment, as all life is an experiment.

I think that, as life is action and passion, it is required of a man that he should share the passion and action of his time at peril of being judged not to have lived.

Freedom of expression matters most where the expression in question is unpopular: if it is to mean anything, it must mean ‘freedom for the thought that we hate.