Liberals have always held that opinion should be formed by untrammeled debate, not by allowing only one side to be heard. Tyrannical governments, both ancient and modern, have taken the opposite view... Among the academic victims of German persecution in Poland there are, to my knowledge, some eminent logicians who are completely orthodox Catholics. I should do everything in my power to obtain academic positions for these men, in spite of the fact that their coreligionists do not return the compliment.
The fundamental difference between the liberal and the illiberal outlook is that the former regards all questions as open to discussion and all opinions as open to a greater or less measure of doubt, while the latter holds in advance that certain opinions are absolutely unquestionable, and that no argument against them must be allowed to be heard. What is curious about this position is the belief that if impartial investigation were permitted it would lead men to the wrong conclusion, and that ignorance is .... therefore, the only safeguard against error. This point of view is one which cannot be accepted by any man who wishes reason rather than prejudice to govern human action...
Uniformity in the opinions expressed by teachers is not only not to be sought, but is, if possible, to be avoided, since diversity of opinion among preceptors is essential to any sound education. No man can pass as educated who has heard only one side on questions as to which the public is divided. One of the most important things to teach in the educational establishments of a democracy is the power of weighing arguments, and the open mind which is prepared in advance to accept whichever side appears the more reasonable. As soon as a censorship is imposed upon the opinions which teachers may avow, education ceases to serve this purpose and tends to produce, instead of a nation of men, a herd of fanatical bigots. Since the end of the Great War, fanatical bigotry has revived until it has become over a great part of the world as virulent as during the wars of religion. All those who oppose free discussion and who seek to impose a censorship upon the opinions to which the young are to be exposed are doing their share in increasing this bigotry and in plunging the world further into the abyss of strife and intolerance from which Locke and his coadjutors gradually rescued it...
In every state, I repeat, no matter what its form of government, the preservation of freedom demands the existence of bodies of men having a certain limited, independence of the state, and among such bodies it is important that universities should be included...
The persecution of unpopular forms of intelligence is a very grave danger to any country, and has not infrequently been the cause of national ruin. The stock example is Spain, where the expulsion of the Jews and Moors led to the decay of agriculture and the adoption of a completely mad finance...
I think there is still some justice, though less than in De Tocqueville’s day, in the following passage:
In America the majority raises very formidable barriers to the liberty of opinion: within these barriers an author may write whatever he pleases, but he will repent it if he ever step beyond them. Not that he is exposed to the terrors of an auto-da-fe, but he is tormented by the slights and persecutions of daily obloquy. His political career is closed forever, since he has offended the only authority which is able to promote his success. Every sort of compensation, even that of celebrity, is refused to him. Before he published his opinions he imagined that he held them in common with many others; but no sooner has he declared them openly than he is loudly censured by his overbearing opponents, whilst those who think without having the courage to speak, like him,abandon him in silence. He yields at length, oppressed by the daily efforts he has been making, and he subsides into silence, as if he was tormented by remorse for having spoken the truth.
... all serious intellectual progress depends upon a certain kind of self respect, a certain kind of independence of outside opinion, which cannot exist where the will of the majority is treated with that kind of religious respect which the orthodox give to the will of God. A respect for the will of the majority is more harmful than respect for the will of God, because the will of the majority can be ascertained...
Collective wisdom, alas, is no adequate substitute for the intelligence of individuals. Individuals who opposed received opinions have been the source of all progress, both moral and intellectual. They have been unpopular, as was natural. Socrates, Christ, and Galileo all equally incurred the censure of the orthodox. But in former times the machinery of suppression was far less adequate than it is in our day, and the heretic, even if executed, still obtained adequate publicity...
Of what importance, it may be said, is such a question as academic freedom in a world distracted by war, tormented by persecution, and abounding in concentration camps for those who will not be accomplices in iniquity ? In comparison with such things, I admit, the issue of academic freedom is not in itself of the first magnitude. But it is part and parcel of the same battle. Let it be remembered that what is at stake, in the greatest.issues as well as in those that seem smaller, is the freedom of the individual human spirit to express its beliefs and hopes for mankind, whether they be shared by many or by few or none. New hopes, new beliefs, and new thoughts are at all times necessary to mankind, and it is not out of a dead uniformity that they can be expected to arise."
--- Freedom and the Colleges / Bertrand Russell