Although little folk are often told to live with man and to help him, they vanish wailing if man lies in wait for them and watches them. Their behaviour is surprisingly analogous to the functioning of instincts. Instincts work, as it were, in the dark, in an unconsidered and unconscious way and consciousness has no part in their hidden game. Conscious and instinctive behaviour even exclude each other. On the other hand the little folk and their clandestine activities are strangely akin to the phenomena of all kinds of spooks. For if, in the morning, the rooms are swept, the saucepans scoured and the cheese ready without a human being having stirred a finger, this is a happy and fairy-like transposition of certain parapsychological or ghostly phenomena. In such phenomena mechanical changes may take place without assignable cause. The legend of the dwarfs who do not want to be seen points to the difficulty, indeed the impossibility, of getting to the bottom of these phenomena; they vanish when we "lie in wait" for them, i.e. when we begin to measure, to photograph, to make statistics and to attempt to capture them with the complex apparatus of modern science. These apparitions apparently have to do with creative, acausal processes, closely bound up with instinct and with man's unconscious nature. They can scarcely be herded into the field of human intellect, and that of time, space and causality. They happen, and if we look closer, they are not there. This is no proof that they do not exist, but it may be a proof of their existence in a domain which is to a large extent removed - for the present at any rate - from the arbitrariness of intellect and the world of the ego.