Private property was the original source of freedom. It still is its main bulwark.

When everyone thinks the same, nobody is thinking.

There is no arguing with the pretenders to a divine knowledge and to a divine mission. They are possessed with the sin of pride, they have yielded to the perennial temptation.

For in the absence of debate unrestricted utterance leads to the degradation of opinion. By a kind of Greshams law the more rational is overcome by the less rational, and the opinions that will prevail will be those which are held most ardently by those with the most passionate will. For that reason the freedom to speak can never be maintained merely by objecting to interference with the liberty of the press, of printing, of broadcasting, of the screen. It can be maintained only by promoting debate.

The radical novelty of modern science lies precisely in the rejection of the belief... that the forces which move the stars and atoms are contingent upon the preferences of the human heart.

The unexamined life, said Socrates, is unfit to be lived by man. This is the virtue of liberty, and the ground on which we may justify our belief in it, that it tolerates error in order to serve truth.

The tendency of the casual mind is to pick out or stumble upon a sample which supports or defies its prejudices, and then to make it the representative of a whole class.