382 



SCIENCE 



[N. S. Vol. XXVII. No. 



of some of the contributions which it is in 

 position to offer in return for favors re- 

 ceived. I choose this course in the hope of 

 furthering among the distinguished nat- 

 uralists here present a fuller understand- 

 ing and appreciation of the ideals, aims, 

 and necessities of modern psychology. 



In emphasizing the demands psychology 

 makes I am by no means oblivious to the 

 inestimable services already rendered her 

 by the natural sciences, but I may safely 

 assume that the more important of these 

 services are familiar to you and I prefer to 

 attempt to make vivid the future favors 

 for which we look. 



It should be remembered at the outset 

 that historically psychology arose out of 

 philosophy, and it still retains a large 

 measure of intimate filial relations with its 

 first parent. In recent years, however, it 

 has been increasingly adopting the man- 

 ners and point of view of its brothers and 

 sisters, the natural sciences. This has been 

 particularly true since the introduction 

 into psychology of experimental methods. 

 - Although there are not at present any 

 sharp lines of division between what may 

 be called philosophical psychology and 

 psychology as a natural science, the dis- 

 tinction in emphasis is none the less real. 

 I shall, for the present pui'pose, disregard 

 the more philosophical branches of psy- 

 chology and confine myself to those of a 

 more scientific character whose relations to 

 the biological sciences are necessarily most 

 intimate. 



It should perhaps be added that the 

 psychology of this stripe conceives its busi- 

 ness as the study of the organization and 

 operations of mind; broadly and meta- 

 phorically, this field may be called the 

 anatomy and physiology of mind. More- 

 over, it regards the mind not as a remote, 

 abstract metaphysical entity, but as a con- 

 crete vital function bound up in the most 



intimate connection with physiological 

 processes which must be taken into account 

 before it can be properly and fully under- 

 stood. 



Perhaps the most persistent and im- 

 portant levies which psychology imder- 

 takes to make are at the expense of neu- 

 rology, using this term to designate the 

 scientific study of both the anatomy and 

 physiology of the nerves, it being under- 

 stood that this includes certain phases of 

 physiological physics and chemistry. The 

 situation here is so obvious and so familiar 

 as to require little elaboration. For 

 modern psychology, the hypothesis that the 

 mind is functionally dependent upon the 

 nervous system has become substantially a 

 postulate. Whatever we can learn, there- 

 fore, about the nervous system, is clear 

 gain to us in our efforts to disentangle the 

 complexity of mental life and to apprehend 

 its principles of organization. We wish to 

 know everything which the neurologists 

 can tell us regarding the ways in which 

 nervous currents act, how they reinforce 

 one another, how they are inhibited, and 

 what are the conditions of their original 

 arousal. We wish to know also, more com- 

 pletely than we now do, what the great 

 typical pathways are through the nervous 

 system and what junction arrangements 

 these pathways have with one another. 

 These facts we wish for the light which 

 they may throw upon certain recognized 

 peculiarities of mental process. What ex- 

 planation, for example, can the neurologist 

 offer us for such peculiar facts as are dis- 

 closed by the syntesthesias, in which the 

 stimulation of one sense organ like the ear 

 is immediately followed by sensations not 

 only of sound but of color or taste ? What 

 explanation can he offer for the fact that 

 - the color threshold is lowered by the simul- 

 taneous stimulation of the ear ? 



We should like to know what occurs as 



