MICHAEL SHERMER: If we can't think and say what we want, how are we going to understand the nature of reality and the way the world works without communications? And without that then all other rights – the right to worship religiously or the right to assemble, the right to debate and dispute and criticize the government and then all the others that fall from that – civil rights, women's rights, gay rights, animal rights and so on...all of it depends on us understanding the nature of reality and it depends on us communicating. The reason for that comes straight out of cognitive psychology. That is, we are wrong about so much of what we believe that the only way to find out if you're on the right track or you've gone off the rails is to actually talk to other people.

Even if you're completely right, by listening to what somebody else says you have an opportunity to strengthen your own position, as John Stuart Mill said in his foundational text in 1859 "On Liberty": "He who knows only his own position doesn't even know that." So, for example, most of my students that I teach they're pretty liberal. They're pro-choice on the abortion issue. but when I ask them to articulate the pro-life position, which over half of Americans take, they mostly can't do it. I tell them that you don't really understand pro-choice arguments if you don't understand the pro-life arguments. You've got to have both sides.

Even if the pro-choice position is absolutely the right one, you're still not really understanding until you understand the other side. Then there's the fact that you might be wrong, partially wrong, or completely wrong. And again, the only way to find out is by listening to what other people say. Then there's the right not just of the speaker to speak, but of the listeners to listen. So when protesters shut down talks at say colleges and universities when a Conservative comes to speak, it's not just the right of the speaker to speak or the administrators or deans who brought that person in, but the audience. There might be a lot of students that want to hear what this person has to say. And even if they are completely liberal and totally opposed to this Conservative's ideas, they still have a right to hear if they want to. And so when protesters get these speakers de-platformed, that is they're not even allowed to speak, they don't even come to campus or if they do come and they try to speak and then they're shouted down – it's called the heckler's veto – that's violating the rights of listeners, not just the speakers.

I'll tell you how far I go in defending free speech. I would defend the free speech of Holocaust deniers. My example of this is David Irving, who's the most prominent of the Holocaust deniers. I've known him a long time, since the 1990's. He's definitely the smartest of the bunch and I think he's absolutely wrong, and I've confronted him with what I think, why I think he's wrong. And as is apparent in his trial, he's also pretty anti-Semitic, or at least he lies for Hitler. But that's beside the point. The idea that he went to Austria to give a talk and was arrested at the airport. They scan your passport and the name pops up and they call the police and they come and arrest him. He was tried and then convicted and put in jail. And he didn't even give a speech. He was just thinking about giving a speech. So that is the very definition of a thought crime. Do we really want to go down that road? I mean that's what countries like North Korea do. That's what the Soviet Union did under Stalin, arrest people for thought crimes. This is a terrible way to go and I even went so far as to write a letter to the judge in that case on behalf of David Irving, even though I completely disagree with him, because I just find this abhorrent. It's like in some countries you can't purchase "Mein Kampf." Are you kidding me? I mean this book should be widely read. It's a terrible read. It's really boring. It's pedantic and rambling and anti-Semitic to the core.

But if we don't understand why people think the way they do, we're never going to be able to end discrimination and hatred, bigotry, racism, anti-Semitism, and so on. That's the only way to do it. Expose it for the erroneous idea that it is and then move on.