"The only source of improvement is liberty, combined with the power of individuals to think for themselves."

"The object of this Essay is to assert one very simple principle, as entitled to govern absolutely the dealings of society with the individual in the way of compulsion and control, whether the means us…"

"The whole of mankind has a right to the benefit of the best ideas, which can only be produced by freedom of thought."

"To be prevented from doing what one is inclined to do, is bondage."

"The only security against error is in the discussion of every subject, with the greatest freedom of speech."