"The peculiar evil of silencing the expression of an opinion is that it is robbing the human race; posterity as well as the existing generation, those who dissent from the opinion, still more than those who hold it. If the opinion is right, they are deprived of the opportunity of exchanging error for truth; if wrong, they lose, what is almost a great a benefit, the clearer perception and livelier impression of truth, produced by its collision with error."
~John Stuart Mill
"Truth is one forever absolute, but opinion is truth filtered through the moods, the blood, the disposition of the spectator." ~Wendell Phillips
"We should be eternally vigilant against the attempts to check the expression of opinions that we loathe."
~Oliver Wendell Holmes, Jr.