There is an amusing story of an opium-eater who, half asleep, half awake, was lying on the grass with his hat on his knees, thinking, "Suppose a thief came along, what would I do?" And no sooner had he thought this than he saw a thief before him. He looked for a stick, and he struck the thief hard, whereupon he woke up suddenly and said, "Well, you gave it to me, but I gave it to you back all right!" There was no thief; it was his own knee; his knee with his hat on it appeared for the moment to be a thief because the thought of a thief was in his mind. He gently, slowly, raised his stick, and when he struck he never thought that he would strike himself. In this moment there was fear, there was a thief, there was a fight, and there was a hurt; and what was it all? He himself.