STEVEN PINKER: My name is Steven Pinker. I am a professor of psychology at Harvard University. I am a cognitive scientist and my new book is called “When Everyone Knows That Everyone Knows, Common Knowledge and the Mysteries of Money, Power and Everyday Life. “The Hidden Psychology Behind Common Knowledge.” There is a big, powerful idea floating around linguistics and philosophy and economics and game theory. That’s really a psychological phenomenon. I am a cognitive psychologist. And it drives many phenomena, explains many mysteries, and not enough people know about it. It is the concept called common knowledge. It has a bit of a technical meaning that is not the same as the way we use common knowledge in everyday conversation. We often say, “Well, it’s common knowledge around here that you could bribe the police.” Kind of an open secret. But common knowledge in a technical sense almost means the opposite. Namely, it’s something that not only does everyone know it, but everyone knows that everyone knows it and everyone knows that and everyone knows …