“The idea that human beings are endowed with a special faculty for reasoning about other minds fits into a much wider and older tradition of debate about the origin of all concepts, especially relatively complex ones. Most psychologists would grant that some basic perceptual primitives—for example, color, sound, and depth—are derived from the physical world by dedicated innate mechanisms in the mind. But where do more abstract concepts come from—concepts such as house, belief, or justice? How, for example, does a child originally learn that other people have beliefs?” —Rebecca Saxe, Boston Review