August 4, 1898J 



NATURE 



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pursuance of this task Mr. Cornelius first devotes 

 a chapter to the question, " What are the ulti- 

 mate elements into which mental processes can be 

 resolved by analysis ? " and then proceeds to trace in 

 detail the formation of derivative psychical products of 

 ever-increasing complexity. In this way he passes in 

 review, one after another, all the most important con- 

 cepts of physics, .-esthetics and ethics. The most 

 noticeable feature of the chapter on the elementary pro- 

 cesses is the admission of "ideas" by the side of sens- 

 ations as a distinct class of primitive mental facts. It 

 is significant that the two best " Psychologies" of recent' 

 years, those of Stout and Ebbinghaus, agree in this 

 rejection of the old theory that an " idea " is merely a 

 weaker " impression." Among the many admirable 

 things in Mr. Cornelius' work, which space will not allow 

 me to mention in detail, specially admirable are the 

 careful and elaborate account in Chapter ii. of the growth 

 and meaning of the concept of objective existence and 

 the discussion of the concept of "truth" in Chapter vi. 

 Mr. Cornelius' philosophical position is, as becomes a 

 follower of Avenarius, one of " naive realism " ; that is, 

 he contents himself with explaining how the plain man's 

 ordinary notions of objective existence, of things and of 

 causes, naturally arise from the workings of the psycho- 

 logical mechanism; and he abstains from any metaphysical 

 theories as to the agreement or disagreement of these 

 notions with " reality." P'erhaps it may be necessary to 

 remark, for the benefit of any one to whom the term is 

 new, that " naive realism " is, in fact, almost the same 

 doctrine as the " idealism " of Berkeley's " Three 

 Dialogues." 



Physiological psychology falls outside the scope of 

 Mr. Cornelius' treatise, and is explicitly relegated in his 

 introduction to its proper place as a useful appendage to 

 the direct investigation of mental phenomena ; he has, 

 however, some ingenious remarks on the "ambiguous" 

 character of the relation between stimulus and sens- 

 ation which challenge the validity of current methods 

 of formulating the results gained by the " method of 

 just perceptible alterations." His contention, which 

 certainly seems reasonable, is that as the position of the 

 " Unterschiedschwelle " in any series of experiments 

 depends largely upon the direction in which the changes 

 of stimulus have been taking place, it is not permissible 

 to assign to it a value derived by taking the arithmetical 

 mean of the values obtained by varying the stimulus in 

 both directions. 



Prof. Titchener's " Primer " is a brief and brightly- 

 written account of the main facts of psychology as seen 

 by a disciple of Wundt, and is better adapted than any 

 work which has as yet come into the present reviewer's 

 hands to serve as a first book for the beginners for whom 

 it is designed. Two most excellent features of the little 

 book, from this point of view, are the price list of psycho- 

 logical apparatus, and the often singularly ingenious 

 problems and exercises appended to the various chapters 

 for home or class work. As was to be expected from 

 Prof Titchener, the standpoint adopted throughout is 

 that of the new "experimental" school. Here and there 

 one may notice little points of detail, which it is to be 

 hoped the author will improve in a second edition. For 

 instance, the statement on p. 40, that "colours" are 

 NO. 1 50 1, VOL. 58] 



" really mixtures of pure colour and brightness " seems 

 to involve a confusion between colour as directly per- 

 ceived (psychological colour) and the physical and 

 physiological conditions of colour perception. Again, 

 the treatment of " Weber's law," on p. 50, is so brief and 

 meagre as to be rather harmful than helpful to a 

 beginner. There should surely have been some attetript 

 to explain to the beginner what is meant by saying that 

 a certain sensation of pressure, 2P, is double another 

 sensation P. In asserting, with rather more confidence 

 than the ascertained facts seem to warrant, the existence 

 of special "pain-spots" in the skin, as well as in ex- 

 tending the conception of association to cover virtually 

 the whole ground of mental synthesis. Prof Titchener is 

 presumably following the lead of his master's " Physi- 

 ologische Psychologie."' There is also, perhaps, an excess 

 of loyalty in the adoption of the Wundtian theory about 

 the functions of the frontal lobes (p. 90-91). These 

 however are, after all, very minor blemishes in a work 

 which is on the whole admirably adapted for interesting 

 the young student in a difficult and to some extent 

 repellent subject. It should perhaps be mentioned that 

 the present work is quite independent of the author's 

 " Outlines of Psychology.'' 



Prof. Ladd's " Outlines of Descriptive Psychology " 

 covers much the same ground as Prof Titchener's little 

 book, and is addressed to the same class of readers. As 

 compared with Prof Titchener, Prof Ladd can hardly be 

 recommended to the beginner as a good master. His 

 style is difficult and slightly verbose, while the comparative 

 paucity of experimental detail and the constant reitera- 

 tion of vague qualifying phrases, like " as it were," " so 

 to say," suggest that he does not always feel quite sure of 

 his ground. The fact is there is far too much for the 

 beginner in Prof. Ladd's " Outlines." There is a good 

 deal of implied metaphysics which can only puzzle a 

 young student, and even apart from the metaphysics, 

 which are probably unconscious, some of the more com- 

 plicated psychological problems are dealt with in a way 

 that is at once too difficult for the beginner, and too 

 short and easy for the advanced psychologist. It would 

 for instance, have perhaps been better in a work designed 

 as a first book for beginners, to say nothing about the 

 controversy between "nativist " and "empiricist" views 

 of space-perception ; but, if the matter was to be intro- 

 duced at all, a view that has the support of such authori- 

 ties as Stumpf and James, should not have been dismissed 

 with the curt reflection, " this view is . . . obviously 

 false." Prof Ladd is perhaps at his best in one or two 

 of the later and more specially philosophical chapters, 

 notably in the last of all, which contains, besides a good 

 summary of the ascertained facts about brain localisation 

 — in which, however, Flechsig is rather disrespectfully 

 treated — a really excellent defence of the popular view of 

 the relation of mind to body. 



The posthumously published little pamphlet of W. 

 Przibram is devoted to an attempt to construct a mathe- 

 matical theory of sensation by means of the symbol 

 t(= \/-i) and its successive powers. Of the value of 

 Mr. Przibram's tract as a contribution to mathematics, 

 I am hardly competent to judge ; the singular arbitrari- 

 ness of its psychological assumptions seems to me to 

 deprive it 0/ any serious significance for the psychologist. 



