When human brains try to do things, they can run into some very strange problems. Self-deception, confirmation bias, magical thinking-it sometimes seems our ingenuity is boundless when it comes to shooting ourselves in the foot. In Map and Territory, decision theorist Eliezer Yudkowsky asks what a "martial art" of rationality would look like, beginning with the basic fighting stance-the orientation toward the world that lets us get the most bang for our cognitive buck, that best positions us to understand and react to brains' strange acts of self-destruction.