Motor automatisms, as I define them, are phenomena of very wide range. We have encountered them already many times in this book. We met them in the first place in a highly developed form in connection with multiplex personality in Chapter II. Numerous instances were there given of motor effects, initiated by secondary selves without the knowledge of the primary selves, or sometimes in spite of their actual resistance. All motor action of a secondary self is an automatism in this sense, in relation to the primary self. And of course we might by analogy extend the use of the word still further, and might call not only post-epileptic acts, but also maniacal acts, automatic; since they are performed without the initiation of the presumedly sane primary personality. Those degenerative phenomena, indeed, are not to be discussed in this chapter. Yet it will be well to pause here long enough to make it clear to the reader just what motor automatisms I am about to discuss as _evolutive_ phenomena, and as therefore falling within the scope of this treatise;--and what kind of relation they bear to the dissolutive motor phenomena which occupy so much larger a place in popular knowledge. In order to meet this last question, I must here give more distinct formulation to a thesis which has already suggested itself more than once in dealing with special groups of our phenomena. _It may be expected that supernormal vital phenomena will manifest themselves as far as possible through the same channels as abnormal or morbid vital phenomena, when the same centres or the same synergies are involved._ To illustrate the meaning of this theorem, I may refer to a remark long ago made by Edmund Gurney and myself in dealing with "Phantasms of the Living," or veridical hallucinations, generated (as we maintained), not by a morbid state of the percipient's brain, but by a telepathic impact from an agent at a distance. We observed that if a hallucination--a subjective image--is to be excited by this distant energy, it will probably be most readily excited in somewhat the same manner as the morbid hallucination which follows on a cerebral injury. We urged that this is _likely_ to be the case--we showed ground for supposing that it _is_ the case--both as regards the mode of evolution of the phantasm in the percipient's brain, and the mode in which it seems to present itself to his senses.