“Beware of false knowledge; it is more dangerous than ignorance.”

“Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity.”

“The one thing that is more dangerous than true ignorance is the illusion of understanding.”

“Beware: the Government Is Armed and Dangerous.”

“In friendship as well as love, ignorance very often contributes more to our happiness than knowledge.”

“It is almost as difficult to make a man unlearn his errors as his knowledge. Mal-information is more hopeless than non-information; for error is always more busy than ignorance. Ignorance is a blank sheet, on which we may write; but error is a scribbled one, on which we must first erase. Ignorance is contented to stand still with her back to the truth; but error is more presumptuous, and proceeds in the same direction. Ignorance has no light, but error follows a false one. The consequence is, that error, when she retraces her footsteps, has further to go, before she can arrive at the truth, than ignorance.”

“They say a little knowledge is a dangerous thing, but it's not one half so bad as a lot of ignorance.”

“Truth is harder to bear than ignorance, and so ignorance is valued more— also because the status quo depends on it; but love depends on self-knowledge and self-knowledge depends on being able to bear the truth.”

“There is no method of reasoning more common, and yet none more blameable, than in philosophical debates to endeavour to refute any hypothesis by a pretext of its dangerous consequences to religion and morality. When any opinion leads us into absurdities, 'tis certainly false; but 'tis not certain an opinion is false, because 'tis of dangerous consequence.”

“Even as a youngster, though, I could not bring myself to believe that if knowledge presented danger, the solution was ignorance.”