452 PHYSIOLOGY CHAP. 



Every one will allow that our psychical capacity aiid inherited 

 cognitions develop and grow and increase progressively, in 

 consequence of the gradual and methodical exercise of our mental 

 powers. Every psychical experience, each new perception and 

 thought, leave a record in the mind, by adding to our inherited 

 memories, altering our affectivity, developing our habits, and 

 forming our tendencies. If we want to express these changes 

 and integrations, of the nature of which we are totally ignorant, 

 in terms of physiology, that is of external observation, we say 

 that every psychical experience leaves a material trace in the 

 higher nerve-centres, facilitates the conduction of the impulses 

 along given neural paths, creates, or at least opens up, new 

 associative ways between the different centres which are involved 

 in the manifold and complex psychical processes. If, on the 

 contrary, we want to express the same fact in psychological terms, 

 i.e. of introspection, we say that each new psychical experience is 

 a transitory phenomenon in relation to self, but persistent and 

 continuous in relation to the deeper and hidden regions of our 

 mind which are constantly active, even when this activity drops 

 below the threshold into the subconscious. 



Neither the one nor the other interpretation of the develop- 

 ment and integration of the mind gives a true scientific explanation 

 of it : they merely offer a working concept or hypothesis, with no 

 objective value, and are wholly inadequate to explain the mysterious 

 relation that exists between the mind and the nervous system. 

 This is evident, as Assagioli points out, from the severe criticism 

 of methods and scientific postulates made by the most modern 

 scientific philosophers, especially Pearson, Clerk-Maxwell, Ostwald, 

 Mach, Le Koy, Poincare. 



In favour of the psychological interpretation it should never- 

 theless be noted that the subconscious as a psychical activity 

 entirely divested of consciousness is inconceivable, and that there 

 are other facts which appear to confute the thesis of unconscious 

 cerebration, with its corollary of the absolutely unconscious in 

 vital phenomena. Some of the arguments based on these facts 

 have been well brought out by William James. 



In speaking of sleep, we saw that it is often accompanied by 

 dreams, which are in themselves an imperfect form of mental 

 activity, because when suddenly awakened during sleep we may 

 be vaguely, sometimes definitely, aware that we had been 

 dreaming. During somnambulance and in hypnosis a consider- 

 able amount of mental activity can be displayed, but all trace of 

 this activity is obliterated on waking. 



Both in the waking state and in conversation, ideas and 

 images often crop up in the mind which are instantaneously 

 effaced, and cannot be reinvoked, making an unpleasant break 

 in the thread of our reasoning. This shows that even during the 



