If you teach a man anything, he will never learn.

It is easy - terribly easy - to shake a man's faith in himself. To take advantage of that to break a man's spirit is devil's work.

For the pre-Darwinian age had come to be regarded as a Dark Age in which men still believed that the book of Genesis was a standard scientific treatise, and that the only additions to it were Galileo'a demonstration of Leonardo da Vinci's simple remark that the earth is a moon of the sun, Sir Humphrey Davy's invention of the safety lamp, the discovery of electricity, the application of steam to industrial purposes, and the penny post.

Nothing can save us from a perpetual headlong fall into a bottomless abyss but a solid footing of dogma; and we no sooner agree to that than we find that the only trustworthy dogma is that there is no dogma.

All censorships exist to prevent anyone from challenging current conceptions and existing institutions. All progress is initiated by challenging current conceptions, and executed by supplanting existing institutions. Consequently, the first condition of progress is the removal of censorship.

The great secret...is not having bad manners or good manners...but having the same manner for all human souls.

I tell you that as long as I can conceive something better than myself I cannot be easy unless I am striving to bring it into existence or clearing the way for it.