The unconscious is shy, elusive, and unwieldy, but it is possible to learn to tap it at will, and even to direct it. The conscious mind is meddlesome, opinionated, and arrogant, but it can be made subservient to the inborn talent through training. By isolating as far as possible the functions of these two sides of the mind, even by considering them not merely as aspects of the same mind but as separate personalities, we can arrive at a kind of working metaphor, impossible to confuse with reality, but infinitely helpful in self-education.