... All ideas need to be heard, because each idea contains one aspect of the truth. By examining that aspect, we add to our own idea of the truth. Even ideas that have no truth in them whatsoever are useful because by disproving them, we add support to our own ideas.

Genius can only breathe freely in an atmosphere of freedom.

A state of things in which a large portion of the most active and inquiring intellects find it advisable to keep the genuine principles and grounds of their convictions within their own breasts, and attempt, in what they address to the public, to fit as much as they can of their own conclusions to premises which they have internally renounced, cannot send forth the open, fearless characters, and logical, consistent intellects who once adorned the thinking world.

Protection, therefore, against the tyranny of the magistrate is not enough; there needs protection against the tyranny of the prevailing opinion and feeling, against the tendency of society to impose, by other means than civil penalties, its own ideas and practices as rules of conduct on those who dissent from them.

What a country wants to make it richer is never consumption, but production. Where there is the latter, we may be sure that there is no want of the former. To produce, implies that the producer de_sires to consume; why else should he give himself useless labor? He may not wish to consume what he himself produces, but his motive for producing and selling is the desire to buy. Therefore, if the producers generally produce and sell more and more, they certainly also buy more and more.

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

The moment one asks himself whether he is happy, he ceases to be so.