All attempts by the State to bias the conclusions of its citizens on disputed subjects, are evil.

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.

A [psychological] difficulty is not an impossibility.

There is an imaginary circle drawn around every human being, over which no government should be able to step.

Pleasure and freedom from pain, are the only things desirable as ends.

Truth gains more even by the errors of one who, with due study and preparation, thinks for himself, than by the true opinions of those who only hold them because they do not suffer themselves to think.

Whether moral and social phenomena are really exceptions to the general certainty and uniformity of the course of nature; and how far the methods, by which so many of the laws of the physical world have been numbered among truths irrevocably acquired and universally assented to, can be made instrumental to the gradual formation of a similar body of received doctrine in moral and political science.