And here I should wish to give a much wider generality to this principle, and to argue that if there be within us a secondary self aiming at manifestation by physiological means, it seems probable that its readiest _path of externalisation_--its readiest outlet of visible action--may often lie along some track which has already been shown to be a line of low resistance by the disintegrating processes of disease. Or, varying the metaphor, we may anticipate that the partition of the primary and the secondary self will lie along some plane of cleavage which the _morbid_ dissociations of our psychical synergies have already shown themselves disposed to follow. If epilepsy, madness, etc., tend to _split up_ our faculties in certain ways, automatism is likely to split them up in ways somewhat resembling these. But in what way then, it will be asked, do you distinguish the supernormal from the merely abnormal? Why assume that in these aberrant states there is anything besides hysteria, besides epilepsy, besides insanity? The answer to this question has virtually been given in previous chapters of this book. The reader is already accustomed to the point of view which regards all psychical as well as all physiological activities as necessarily either developmental or degenerative, tending to evolution or to dissolution. And now, whilst altogether waiving any teleological speculation, I will ask him hypothetically to suppose that an evolutionary _nisus_, something which we may represent as an effort towards self-development, self-adaptation, self-renewal, is discernible especially on the psychical side of at any rate the higher forms of life. Our question, Supernormal or abnormal?--may then be phrased, Evolutive or dissolutive? And in studying each psychical phenomenon in turn we shall have to inquire whether it indicates a mere degeneration of powers already acquired, or, on the other hand, the "promise and potency," if not the actual possession, of powers as yet unrecognised or unknown. Thus, for instance, Telepathy is surely a step in _evolution_.[160] To learn the thoughts of other minds without the mediation of the special senses, manifestly indicates the possibility of a vast extension of psychical powers. And any knowledge which we can amass as to the conditions under which telepathic action takes place will form a valuable starting-point for an inquiry as to the evolutive or dissolutive character of unfamiliar psychical states.[161]