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SCIENCE 



[N. S. Vol. XXVII. No. CSS 



anee, then the term "unknoiun" should be 

 substituted for it in the regions concerned. 



There are many general advantages of a 

 similar character to be gained by the sci- 

 entist from a slight acquaintance with 

 psychology, and not the least of these is 

 perhaps the more vivid appreciation on his 

 part of the elaborate technique which 

 modern psychology has worked out to meet 

 her needs and the substantial foundation 

 which now underlies modern psychological 

 doctrines. In so enlightened a body of 

 scientists as this which I now have the 

 honor to address, there is undoubtedly no 

 such shallow misconception of the attain- 

 ments of modern psychology, but there are 

 many who still dwell in the darkness of 

 intellectual night so far as concerns this 

 matter. 



I shall select simply a point or two to 

 illustrate the more specific and particular 

 ways in which psychology may contribute 

 to the natural sciences. The contemporary 

 naturalist often has occasion to make use 

 of the psychological principle of associa- 

 tion and I would urge on his thoughtful 

 consideration the psychological analyses of 

 this feature of mental life. The bland 

 naivete with which he often uses this prin- 

 ciple makes one gasp who has ever faced 

 its multitudinous complexities. It is a 

 safe surmise that Aristotle had forgotten 

 more about the principle of association 

 than certain modern naturalists have ever 

 known. It is respectfully submitted that 

 it is not good common sense in the use of a 

 principle like this wholly to disregard the 

 elaborate analyses of generations of 

 previous workers. Again, it is out of the 

 question for the neurologist, for instance, 

 studying the function of the auditory end- 

 organ apparatus to go far or safely with- 

 out a knowledge of such generally un- 

 familiar phenomena as those of combina- 

 tion tones with their many varieties. 

 Similarly the physiology of the visual 



processes must remain lamentably incom- 

 plete in the hands of an investigator un- 

 familiar with the important facts of color 

 vision: for example, the peculiarities of 

 such vision under dark and light adapta^ 

 tions respectively, the phenomena of con- 

 trast, peripheral retinal color deficiency, 

 the peculiarities of peripheral and foveal 

 space impressions, and so on. In other 

 words, psychology is in a position to 

 furnish a systematized statement of vast 

 ranges of mental phenomena which not 

 only may be taken into account by the 

 neurologist, but which must be taken into 

 account before his science can approach 

 completion, because these phenomena con- 

 stitute many of the concrete facts which 

 it is his business to explain. In other 

 words, psychology— or some other science 

 doing her work— sets many of the most im- 

 portant problems for the other biological 

 sciences. Facts which she finds, they must 

 take account of and, if possible, explain. 

 James Rowland Angell. 

 University of Chicago 



SCIENTIFIC BOOKS 

 The Value of Science. By H. Poinoare, 

 Member of the Institute of France. Au- 

 thorized Translation with an Introduction, 

 by George Bruce Halsted, Ph.D., F.E.A.S. 

 With a Special Prefatory Essay. Pp. iv + 

 147. New York, The Science Press. 190Y. 

 In calling attention to M. Poincare's mas- 

 terly little book, I propose — these columns 

 being what they are — to consider rather its 

 general significance than to traverse the tech- 

 nical problems of logic and epistemology 

 which it raises. For scientific workers at 

 large, the tendency of the monograph happens 

 to be the most important thing about it. It 

 adds another to the numerous contemporary 

 evidences that scientific investigation, when 

 subjected to reflection, and viewed with regard 

 to its , methodology and intellectual presup- 

 positions, leads unavoidably to difficulties that 

 belong in the field of philosophy. No doubt, 

 I may incline to exaggerate this view, but, as 



