The power which a man's imagination has over his body to heal it or make it sick is a force which none of us is born without. The first man had it, the last one will possess it. If left to himself, a man is most likely to use only the mischievous half of the force—the half which invents imaginary ailments for him and cultivates them; and if he is one of these—very wise people, he is quite likely to scoff at the beneficent half of the force and deny its existence. And so, to heal or help that man, two imaginations are required: his own and some outsider's. The outsider, B, must imagine that his incantations are the healing-power that is curing A, and A must imagine that this is so. I think it is not so, at all; but no matter, the cure is effected, and that is the main thing. The outsider's work is unquestionably valuable; so valuable that it may fairly be likened to the essential work performed by the engineer when he handles the throttle and turns on the steam; the actual power is lodged exclusively in the engine, but if the engine were left alone it would never start of itself. Whether the engineer be named Jim, or Bob, or Tom, it is all one—his services are necessary, and he is entitled to such wage as he can get you to pay. Whether he be named Christian Scientist, or Mental Scientist, or Mind Curist, or King's-Evil Expert, or Hypnotist, it is all one; he is merely the Engineer; he simply turns on the same old steam and the engine does the whole work.
Mark Twain