Every established fact which is too bad to admit of any other defence is always presented to us as an injunction of religion.

The struggle between Liberty and Authority is the most conspicuous feature in the portions of history with which we are earliest familiar; particularly in that of Greece, Rome, and England

The peculiar evil of silencing the expression of an opinion is, that it is robbing the human race; posterity as well as the existing generation; those who dissent from the opinion, still more than those who hold it. If the opinion is right, they are deprived of the opportunity of exchanging error for truth: if wrong, they lose, what is almost as great a benefit, the clearer perception and livelier impression of truth, produced by its collision with error.

A population may be too crowded, though all be amply supplied with food and raiment. It is not good for a man to be kept perforce at all times in the presence of his species.

The peculiarity of the evidence of mathematical truths is that all the argument is on one side.

To think that because those who wield power in society wield in the end that of government, therefore it is of no use to attempt to influence the constitution of the government by acting on opinion, is to forget that opinion is itself one of the greatest active social forces. One person with a belief is a social power equal to ninety-nine who have only interests.

Liberty consists in doing what one desires.