"A library is a sort of catalog or warehouse of all that men think about—so by cataloging a library I can make a more or less orderly and comprehensive list of all the symbols that sapient beings carry around in their heads. But rather than trying to dissect brains and ransack the actual gray matter for those symbols—rather than use the same sorts of symbolic representations that the brain manipulates—I simply assign a prime number to each. Numbers have the advantage that they may be manipulated and processed with the aid of machines—"