The test of real and vigorous thinking, the thinking which ascertains truths instead of dreaming dreams, is successful application to practice.

We often hear the teachers of all creeds lamenting the difficulty of keeping up in the minds of believers a lively apprehension of the truth which they nominally recognize, so that it may penetrate the feelings, and acquire a real mastery over the conduct.... When it has come to be a hereditary creed, and to be received passively, not actively ... there is a progressive tendency to forget all of the belief except the formularies ... until it almost ceases to connect itself at all with the inner life of the human being.

The beliefs which we have most warrant for, have no safeguard to rest on, but a standing invitation to the whole world to prove them unfounded.

All that makes existence valuable to any one depends on the enforcement of restraints upon the actions of other people.

Trade is a social act.

To refuse a hearing to an opinion, because they are sure that it is false, is to assume that their certainty is the same thing as absolute certainty. All silencing of discussion is an assumption of infallibility.

Experience has taught me that those who give their time to the absorbing claims of what is called society, not having leisure to keep up a large acquaintance with the organs of opinion, remain much more ignorant of the general state either of the public mind, or of the active and instructed part of it, than a recluse who reads the newspapers need be.