Okay, before I explain how to find a unified principle which can be applied to all of those sorts of problems. Let me just examine common criticism or concern about formulating human behavior via mathematical model. Okay? I do research in game theory, and whenever I say I do research in game theory in a party, for example, I get three common reactions. Reaction number one oh, wonderful, you do research in video games. Well, I have to disappoint the person, saying that game theory is not about the video game. Common reaction number two, you know, suddenly, you know, they get very defensive, thinking that I'm a very good strategist and I'm going to exploit them by using game theory. Well, I'd say that game theory is not for use, not so usable in exploiting other people, and at least I don't use game theory in that way. The third criticism is that, third common reaction is that well, it shouldn't work, okay? And the reasoning are based on the following three points. So eventually, I'm going to tell you that game theory tries to predict human behavior by a mathematical formula. And the using mathematical formula to explain things have been very successful in natural sciences. A wonderful example is Newton's Law, okay? A, a, the falling ball here goes down at a constant acceleration, that's the Newton's Law and the every time you know, a ball is falling it perfect follow this Newton's Law. Okay. So the question which was posed by the fathers of game theory, von Neumann and Morgenson what's to find something like Newton's Law, which can be applied to all social problems. So the task of game theory is to find a general unified principle to explain people's behavior. By means of some mathematical formula. And people that say well I know this shouldn't work, okay? They are reasoning the following. Number one, it shouldn't work because I have free will. Okay? So I have a freedom to choose any behavior. So the skeptic's point of view number one, is that free will defeats any attempt to predict human behavior by a mathematical formula, okay? Suppose game theory tells you that you must choose, well you should choose certain strategy in a certain social situation. Well, you can always deviate because you have free will, okay? So just by the fact that humans have free will defeats any attempt to predict human behavior. That's the criticism number one, okay? Number two says well, we don't need mathematical theories to explain a perfect human behaviour because eventually, you can ask why did you do that? Why did you do that? RIght? You cannot ask this question to falling ball. It's very silly to ask the ball, why are you falling in this particular way? That's a silly question. But if your subjects are humans, you can ask a question. Why you did that? Okay? Lots of social sciences, sociology, political science, and economics, took that kind of approach, and in good old days economics, was collecting detailed facts about economic phenomenon and economics conducted detailed interviews about the relevant party. And we used to argue that that is a scienti, scientific way of finding out what is happening in a society. This is a down to earth empirical work which finds, which try to find detailed, which try to collect detailed facts and conducting interviews are all we need in social sciences. Basically, that's the, that's what criticism number two says. Okay, criticism number three says, well, I have never seen or heard that game theory works. Okay? If game theory has a wonderful formula to explain everything in human interaction, we must have some evidence but I have never heard of it. And that's the last criticism. Okay? A wonderful example can be found in episode about an economist and a mathematician. And this episode happened sometime around 1939 between two young researchers. Stan Ulam he is a mathematician. And Paul Samuelson, he was a theoretical economist. So they were, they were good friends, and they enjoyed a stimulating conversation every day. But always the mathematicians Stan Ulam was teasing Paul Samuelson by posing the following question. So name me one proposition in all of the social sciences which is both true and non-trivial? Well, Samuelson was studying economics and the economy presents lots of predictions and laws. The famous one says that if the price goes up, the supply goes up, right? And you can prove it by mathematical model. But it's Right? The price of your product is going up then you have an incentive for this more. This is true but it's really trivial. So Stan Ulam was teasing also social sciences by saying that we're also social sciences are saying many things but they are all trivial. And unlike, you know, natural sciences, there is no proposition, no single proposition in all humanity and social sciences which is both true and non-trivial. Well, back in 1939, before the birth of game theory, what did the economist Paul Samuelson say? Well, he couldn't say anything. He said this was a test that I always failed, okay? But then, game theory was created, and now we have some evidence that mathematical approach actually works very well. And I'm going to show you some examples in this week and the next few weeks.