According to Nabokov, when ancient people first invented arithmetic, it was an artificial system designed to impose order on the world. Over the course of centuries, as the system grew more and more intricate, “mathematics transcended their initial condition and became as it were a natural part of the world to which they had been merely applied. . . . The whole world gradually turned out to be based on numbers, and nobody seems to have been surprised at the queer fact of the outer network becoming an inner skeleton.”