Perhaps philosophy’s most famous defense of the freedom of speech was articulated by John Stuart Mill, who defended the ideal in his 1859 work, On Liberty. In chapter 2, “Of the Liberty of Thought and Discussion,” Mill sets out to establish that silencing any opinion is wrong, even if the opinion is false. To silence a false opinion is wrong, because knowledge arises only from the “collision [of truth] with error.” In other words, true belief becomes knowledge only by emerging victorious from the din of argument and disagreement and discussion.
