Imagination is celebrated as our vehicle for escape from the mundane here and now. It transports us to distant lands of magic and make-believe. It provides us with diversions during boring meetings or long bus rides. It enables creation of new things that the world has never seen. Yet the focus on imagination as a means of escape from the real world minimizes the fact that imagination seems also to furnish us with knowledge about it. Imagination seems an essential component in our endeavor to learn about the world in which we live--whether we're planning for the future, aiming to...