John Lancaster Spalding quote: “If our opinions rest upon solid ground, those who attack them do not make us angry, but themselves ridiculous.”

“We took the liberty to make some enquiries concerning the ground of their pretentions to make war upon nations who had done them no injury, and observed that we considered all mankind as our friends who had done us no wrong, nor had given us any provocation.”

Thomas Jefferson (1743–1826) 3rd President of the United States of America

1780s, Letter to John Jay (1786)

“We took the liberty to make some enquiries concerning the ground of their pretentions to make war upon nations who had done them no injury, and observed that we considered all mankind as our friends who had done us no wrong, nor had given us any provocation.”

John Adams (1735–1826) 2nd President of the United States

1780s, Letter to John Jay (1786)

“I am inclined to believe that few attacks either of ridicule or invective make much noise, but by the help of those they provoke.”

Samuel Johnson (1709–1784) English writer

Letter to Hester Thrale (5 July 1783) http://books.google.com/books?id=8JuiYLGldcsC&pg=PA169&lpg=PA169&dq=%22samuel+johnson%22+few+attacks+ridicule+invective+noise+provoke&source=web&ots=HMST_SM18L&sig=xovCcC2lKiTX9V0p61QvIC_yHW0&hl=en&sa=X&oi=book_result&resnum=1&ct=result

“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.”

John Stuart Mill book On Liberty

Source: On Liberty (1859), Ch. II: Of the Liberty of Thought and Discussion

“I do not agree with the extremists of either the left or the right, but I think they should be allowed to speak and to publish, both because they themselves have, and ought to have, rights, and once their rights are gone, the rights of the rest of us are hardly safe. Extremists typically want to squash not only those who disagree with them diametrically, but those who disagree with them at all.”

Jane Jacobs (1916–2006) American–Canadian journalist, author on urbanism and activist (1916-2006)

Political questionnaire response (1952)
Context: The other threat to the security of our tradition, I believe, lies at home. It is the current fear of radical ideas and of people who propound them. I do not agree with the extremists of either the left or the right, but I think they should be allowed to speak and to publish, both because they themselves have, and ought to have, rights, and once their rights are gone, the rights of the rest of us are hardly safe. Extremists typically want to squash not only those who disagree with them diametrically, but those who disagree with them at all. It seems to me that in every country where extremists of the left have gotten sufficiently in the saddle to squash the extremists of the right, they have ridden on to squash the center or terrorize it also. And the same goes for extremists of the right. I do not want that to happen in our country.