You’ve got to love John Stuart Mill:
[…] the peculiar evil of silencing the expression of an opinion is, that is robbing the human race, posterity as well as the current generation, those who dissent from the opinion, even 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 as great a benefit, the clearer perception and livelier impression of truth, produced by its collision with error.
