Once you understand game theory, you understand the world.

- This is a video about the most famous problem in game theory. Problems of this sort pop up everywhere, from nations locked in conflict to roommates doing the dishes. Even game shows have been based around this concept. Figuring out the best strategy can mean the difference between life and death, war and peace,

flourishing and the destruction of the planet. And in the mechanics of this game, we may find the very source of one of the most unexpected phenomena in nature: cooperation. (upbeat music) On the 3rd of September, 1949, an American weather monitoring plane collected air samples over Japan. In those samples, they found traces of radioactive material.

The Navy quickly collected and tested rainwater samples from their ships and bases all over the world. They also detected small amounts of Cerium-141 and Yttrium-91. But these isotopes have half lives of one or two months, so they must have been produced recently and the only place they could have come from was a nuclear explosion.

But the US hadn't performed any tests that year, so the only possible conclusion was that the Soviet Union had figured out how to make a nuclear bomb. This was the news the Americans had been dreading. Their military supremacy achieved through the Manhattan Project was quickly fading. - This makes the problem of Western Europe

and the United States far more serious than it was before and perhaps makes the imminence of war greater. - Some thought their best course of action was to launch an unprovoked nuclear strike against the Soviets while they were still ahead. In the words of Navy Secretary Matthews to become "aggressors for peace". John von Neuman, the founder of game theory,