CHAPTEE IX 



PSYCHO-PHYSICAL PHENOMENA OF CONSCIOUSNESS AND SLEEP 



CONTENTS. 1. The range of mental life includes unconscious as well as 

 conscious processes. 2. States of complete and incomplete' consciousness. 3. Sub- 

 conscious activity ; its great importance in relation to conduct and genius. 4. 

 Development and integration of the mind a function of the subconscious, based 

 on psycho-physical processes as distinct from conscious processes. 5. Disintegra- 

 tions of personality (double, consciousness, secondary personality, alternating 

 personality). 6. Physiology of sleep. 7. Theories of sleep. 8. Psychology of 

 sleep. 9. Dreams. 10. Telepathic phenomena. Vitalism and materialism. 

 Bibliography. 



IN analysing movements and sensations we have investigated the 

 two extreme phases, terminal and initial, of the processes of animal 

 life. We must now examine the intermediate phases of these 

 processes, which take place in the nervous system, and which 

 include the whole of the complex phenomena that occur as we 

 pass from the Unconscious to the Conscious, in which objective 

 or purely physiological factors assume a subjective or psychological 

 character. 



We know that the nervous system is the substrate of the 

 functions of animal life, and that it brings about the physiological 

 unity and reciprocal interdependence of the organs, on which the 

 psychological unity, expressed in the phenomena of the Ego, or 

 Consciousness, depends. 



Owing to its pragmatical rather than to its intrinsic philo- 

 sophical value, the hypothesis of "psycho-physical parallelism" 

 enables us still to deal with positive phenomena and controllable 

 laws, without crossing the threshold of metaphysics (Chap. I. 2-3). 

 By it we may conclude that each psychical phenomenon or state 

 of consciousness has a somatic basis, a concomitant neural process ; 

 and we may leave to metaphysicians the attempt to solve the 

 problem of how and why, during life, the "soul" whether 

 considered as an entity or as a complex of psychical phenomena 

 must remain intimately connected with the body, and act with 

 or parallel to it. 



Generally speaking, we class as psycho-physical phenomena all 

 those which we know both subjectively and objectively, which, 



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