ON THE PSYCHO-PHYSICAL VIEW OF NATURE. 501 



We must bear in mind this twofold source of Lotze's 

 reflections if we want to estimate correctly the value of 

 his early criticisms regarding the then prevalent treat- 

 ment of such questions as life and mind in the medical 

 sciences. On the one side he had the object of clear- 

 ing the way for purely mechanical explanations. We 

 learnt in an earlier chapter how he was one of those 

 who successfully chased out of biology the vague idea of 

 a vital force. And when he approached the problem 

 of mind and body, we find him insisting on the presence 

 of a psycho-physical mechanism which rules l the inter- 



1 The opinion of Lotze regarding 

 the relation of soul and body, or 

 rather of psychical and physical phe- 

 nomena, has been stated by him, 

 variously, as parallelism, occasional- 

 ism, pre-established harmony, and 

 was ultimately crystallised in the 

 term psycho-physical mechanism. 

 The question is fully discussed in 

 the articles, " Leben und Lebens- 

 kraft," "Instinct," "Seele und 

 Seelenleben," which he contributed 

 to R. Wagner's ' Handworterbuch 

 der Physiologic.' They are re- 

 printed in Lotze's ' Kleine Schrif ten,' 

 ed. D. Peipers, 4 vols. (Leipzig, 

 1885-91). He there says, "The 

 conception of a psycho-physical 

 mechanism can be stated as fol- 

 lows : As ideas, volitions, and other 

 mental states cannot be compared 

 with the quantitative and special 

 properties of matter, but as, never- 

 theless, the latter seem to follow 

 upon the former, it is evident that 

 two essentially different, totally 

 disparate, series of processes, one 

 bodily and one mental, run par- 

 allel to each other. In the intensive 

 quality of a mental process, the 

 extensive definiteness of the material 

 process can never be found ; but if 

 the one is to call forth the other, 



the proportionality between them 

 must be secured through a connec- 

 tion which appears to be extrinsic 

 to both. There must exist general 

 laws, which ensure that with a 

 modification a of the mental sub- 

 stance a modification b of the bodily 

 substance shall be connected, and it 

 is only in consequence of this inde- 

 pendent rule, and not through its 

 own power or impulse, that a 

 change in the soul produces a 

 corresponding one in the body " 

 (vol. i. p. 193). Lotze destroyed 

 the idea of vital force, but he 

 only chased the conception of 

 the soul beyond the limit of the 

 psycho-physical mechanism, and he 

 maintains that natural and medical 

 science have no interest in pursuing 

 the question beyond that limit, 

 "however interesting the further 

 discussion of this subject may be to 

 speculative psychology " (vol. i. p. 

 197) " for it is quite indifferent to 

 medicine, wherein the mysterious 

 union of body and soul consists, as 

 this is the constant event which 

 lies equally at the bottom of all 

 phenomena. But it is of the 

 greatest interest to medicine to 

 know what affections of the soul 

 are connected in that mysterious 



