There is the greatest difference between presuming an opinion to be true, because, with every opportunity for contesting it, it has not been refuted, and assuming its truth for the purpose of not permitting its refutation. Complete liberty of contradicting and disproving our opinion is the very condition which justifies us in assuming its truth for purposes of action; and on no other terms can a being with human faculties have any rational assurance of being right. (pp. 26-27)

Ages are no more infallible than individuals; every age having held many opinions which subsequent ages have deemed not only false but absurd; and it is as cer…

In the case of any person whose judgment is really deserving of confidence, how has it become so? Because he has kept his mind open to criticism of his opinion…

In proportion to a man's want of confidence in his own solitary judgment, does he usually repose, with implicit trust, on the infallibility of 'the world' in g…

'No man -prince, peasant, pope, -has all the light, who says else is a mountebank. I claim no private lien on truth, only a liberty to seek it, prove it in deb…

Much may be said on both sides.

I agree with everything you say, but I would attack to the death your right to say it.