STEVEN PINKER: One reason why we need to keep channels of expression open is that it's possible for people to get trapped in a vicious circle of delusion if they believe something that is not true and if people are punished for pointing out that it's not true. In fact, you could even have a circumstance which no one actually believes something but no one is afraid to express the opposite of that idea out of fear of being punished if they do. And you can – it's sometimes called pluralistic ignorance. It can lead to the madness of crowds where everyone is under some collective delusion or at least expresses a collective of delusion because they don't want to be the first person to break the spiral of silence. They're afraid of being the little boy who says the emperor is naked and entire societies can be under a collective delusion. The ability to express an idea can puncture a bubble of collective false knowledge and is one of the reasons that we have to cherish that freedom.

Let's say you wanted to make an argument against free speech. If I said you can't say that you would immediately say well, wait a sec. I haven't even made my argument yet. The very fact that you're making an argument for anything presupposes that you have the right to express an idea. It may be incorrect but how will we know if it's incorrect or not until it's expressed and it can be evaluated. Also, we know that people are not infallible. They are not omniscient. That throughout the history of ideas there have been people who are absolutely certain that they are correct and history has shown that they've been mistaken. So the fact that we as a species can come up with good ideas, explanations of how the world works in science, ideas about how best to organize our government in politics, ideas about what is morally defensible and indefensible have all come about because people have expressed ideas, thrown them out there, allowed them to be evaluated by others.

The better ones win out but the only reason they won out is that they were expressed in the first place. We just don't know any route to knowledge other than what Karl Popper called conjecture and refutation, throwing an idea out there, seeing if it withstands attempts to falsify it.

In universities above all free speech and freedom of inquiry have to be encouraged because universities are given many perequisites by society. Tax free status, sometimes direct government support, the institution of tenure, the credentialing function that people often can't get a job unless they have a piece of paper from a university. So we invest a lot of trust and resources in a university because they ought to be idea factories, places where ideas are broached, evaluated, tested. If universities aren't doing that then they really don't deserve all the perquisites that societies are giving them. And one of them has to be the airing of ideas that make you uncomfortable. Simply because the fact that an idea makes you uncomfortable has nothing to do with whether it's a good idea or not. It is just a fact of human nature that it's pleasant and enjoyable and empowering to hear ideas that you agree with, that people in your tribe endorse.

It's annoying and upsetting, sometimes hurtful to hear ideas that you disagree with, that your tribe disagrees with. It might call into question your own credibility, your own competence but it ought to be aired for all that because if your feelings are hurt sometimes that's just too bad. You might be wrong no matter how painful it is for that fact to become known. And if you aren't wrong, if you are right how can you know it. How can anyone else know it unless the opposing idea is broached and flaws with it are pointed out. So there's a – our own feelings of discomfort can't be a guide as to which opinions ought to be expressed. And again we just know that no one's smart enough to think up all the good ideas on their own. Successful institutions, successful societies are at intellectual crossroads where people and ideas can flow in and out, the bad ones weeded out, the good ones accumulated. Any vibrant culture, any successful body of knowledge is kind of a greatest hits collection.

It's an assembly of all of the ideas that have at least for now stood the test of time. Now there are cases in which we already restrict free speech in say extortion and bribery and libel, inducements to imminent violence. There are lines that we can draw but they are circumscribed zones in which we say that we feel we have the right to regulate speech. The default is ideas can be aired with a few carefully justified exceptions.