512 



NATURE 



[June 24, 1920 



bar of varying, cross-section and with end-effects 

 in torsion. 



In the chapter dealing- with the elastica, the 

 section (265) which gives the computation of the 

 strain energy of the strut has been practically re- 

 written and much improved. It might be useful, 

 in dealing with buckling, to dispose of a fallacy 

 common among engineers that Euler's limit 

 implies failure of the strut, whereas all that occurs 

 is passage from one type of stable equilibrium to 

 another. 



Southwell's method of deahng with problems of 

 elastic stability comes in, naturally, for consider- 

 able notice. The buckling of a strut (§ 267 a), of 

 a rectangular plate (§ 332), and of a tube (§341) 

 are discussed as examples of this theory. 



An entirely new chapter (xxiv. a) has been 

 added, dealing very exhaustively with the equi- 

 librium of thin shells in the shape of surfaces of 

 revolution, including in particular a discussion of 

 Meissner's work on the spherical and conical 

 shells. 



A feature of this edition (as of the previous 

 ones) is the extraordinarily complete and careful 

 set of references to all the original papers and 

 memoirs dealing with the subject. Needless to 

 say, these references, which have been most 

 thoroughly brought up to date, are invaluable 

 to the reader who takes up the book as a guide 

 to research. The example set by such a master 

 as Prof. Love might well be commended to the 

 younger generation of scientific writers. Too 

 often nowadays, especially in papers dealing with 

 applied science, one comes across a statement of 

 reierences which betrays the author's ignorance of 

 the literature of his subject, both by the omission 

 of work (sometimes of fundamental importance) 

 done by his predecessors, and by the undue prom- 

 inence accorded to the minor efforts of contem- 

 poraries in his own circle. L. N. G. F. 



Behaviourism. 



Psychology from the Standpoint of a Behaviorist. 

 By Prof. John B. Watson. (LIppincott's Col- 

 lege Texts.) Pp. xiii + 429. (Philadelphia and 

 London: J. B. Lippincott Co., 1919.) Price 

 los. 6d. net. 



THERE has been a great deal of controversy, 

 especially in the philosophical journals of 

 America, concerning the theory of behaviourism. 

 Prof. Watson is, we believe, the originator of the 

 term and the recognised leader in its application 

 as a method in psychology. The book before us 

 is not an exposition of the theory ; it takes it as 

 accepted, and puts f orvvard an elementary, but 

 NO. 2643, VOL. 105] 



nevertheless complete, schematic outline of the 

 science of psychology, its scope and its method, 

 regarded from this point of view. It therefore, 

 better than any detailed exposition, sets before us 

 the advantages and the disadvantages, the limita- 

 tions and inclusions and exclusions, of psychology 

 as the behaviourist conceives it. 



Behaviourism is a theory of the science of 

 psychology based on two postulates. The first is 

 that the only thing the psychologist can study 

 scientifically is behaviour. The second is that 

 there is nothing else in psychology to study but 

 behaviour. When the description of an in- 

 dividual's behaviour is exhausted there is no 

 remainder, no psyche, left out of the account. The 

 first postulate is explicit, the second implicit. 

 It is clear at once, however, that the second is 

 fundamental. Analyse the response of an organ- 

 ised material being to the stimulus of a situation, 

 and you have exhausted psychology. Not only 

 have you gone as far as you can go, but there is 

 also no farther to go. 



When you have simplified your science to this 

 extent, the difficulty is to justify it at all. What 

 is the subject-matter of psychology which 

 demands a special method? This is Prof. 

 Watson's difficulty. Physiology is already in the 

 field ; it has accomplished a vast amount of this 

 very behaviour study. What is there left over 

 for psychology? What sort of responses are 

 there to which the physiologist can be, and is, 

 completely indifferent, and which fall under the 

 class-heading, psychological? The (further we 

 read in this book, the more intensely does this 

 inquiry present itself as the crucial question. 

 Three chapters of the book (no inconsiderable 

 portion of the whole) are acknowledged to be 

 pure physiology, and not psychology, and the 

 reader is told in the preface that he may skip 

 these if he likes, and that if he does so he need 

 be at no disadvantage from his point of view as 

 psychologist. But the physiology is not all so 

 easily excised. When Prof. Watson defines an 

 emotion he has to apologise for the impossibility 

 of avoiding physiological terms. How much, one 

 wonders, would be left of the book if all the 

 physiology were taken out and only pure psycho- 

 logy left? The present writer, at least; as he 

 reads the book finds himself in continual expecta- 

 tion that now he is coniing to the end of the 

 physiology and the beginning of the psychology, 

 but is "Continually disappointed, and the reason is 

 clear enough when Prof. Watson gives at last 

 his definition of the distinction of the two 

 sciences. Whenever, he tells us, we are study- 

 ing the response of a part of the organism to a 



