58 Journal of Comparative Neurology and Psychology. 



affect the biologist's conception of the nature of what he calls 

 an organism. Biology, in so far as it pretends to be an exact 

 science, regards the organism as a complicated mechanism 

 whose elements are to be understood in terms of the physical 

 laws which hold for these elements outside the organism. Hence, 

 if, for example, the study of the electrical properties of matter 

 results in transforming our chemical and physical notions, and 

 some form of an energic is substituted for the atomic theory, 

 this dynamic view ultimately must reach into biology with trans- 

 forming effect. 



In a similar way, the conception of the nature of conscious- 

 ness is undergoing reconstruction in psychological science, in 

 part due to this same energistic theory which is transforming 

 physical science. The traditional formula which is satisfied to 

 postulate a soul back of consciousness, just as it postulates ma- 

 terial atoms back of motion or force, appears likely to be 

 eclipsed by the results of inquiries which seek to discover the 

 nature of the intimate relation which certainly seems to exist 

 between mind and matter. There is no blinking the facts of 

 brain structure nor of mental functioning ; the problem is to 

 understand what we mean by each in terms of the other. 



This it has been almost impossible to do in the past be- 

 cause of the diverse historical conditions and techniques associ- 

 ated with the two sciences. Biology had its roots in the natu- 

 ral and positive sciences ; psychology arose as a branch of phil- 

 osophy and was long known as "mental philosophy." But now 

 that the basis has been laid for a scientific psychology, there is 

 hope of its being possible for the psychologist and neurologist 

 to get together in their work on this common problem. 



As has been intimated, this will involve a revision of psy- 

 chological conceptions on many fundamental points. That this 

 is already taking place is evident from recent tendencies in psy- 

 chological thought. Consciousness is coming to be stated more 

 and more in terms of action, in terms of the motor aspect of 

 the organic circuit, instead of being stated exclusively in terms 

 of the sensory aspect, which was the tendency with the older 

 intellectualistic psychology. Great emphasis is now being placed 



