O'SIIEA — ASPECTS OF MENTAL ECONOMY. 45 



can be reduced to material terms. This conception becomes 

 easily established in the evolution alike of the racial and of 

 the individual mind, since the phenomena occurring in mental 

 disease, and particularly in injury to or degeneracy of the cen- 

 tral nervous mechanism lend themselves readily to such inter- 

 pretation. People remark that if the brain suffer damage from 

 any cause some mental defect or deficiency usually ensues ; and 

 when for whatever reason the cerebrum becomes inactive, there 

 is no evidence of any supra-cerebral activity remaining. So 

 far, in short, as we can observe mental activities ab extra, they 

 appear to be directly dependent upon or rather aspects of neural 

 processes. This second view then makes mind a phase or phe- 

 nomenon of matter, — one of a group of physical forces origi- 

 nating in the degradation of highly organized chemical sub- 

 stances. 



There is yet a third hypothesis 1 which regards the mind 

 and the body, so far as it passes opinion upon the essential 

 nature of each, as distinct entities, but in some inexplicable man- 

 ner bound to each other in such a way that the activities of the 

 one necessitate correlated activities in the other. The advocates 

 of this theory pin their faith to what may be styled a dynamic, 

 or better, energeic relation between mind and body. They do 

 not deem it needful to explain how this relation is possible, al- 

 though theories looking in this direction are not wanting. A 

 common one espoused by James and others considers the nerve 

 cell as the instrument, and the sole instrument, by which mind 

 may be displayed in a material world; and if the neural ele- 

 ments which constitute the via media for this physical exhibi- 

 tion of a non-physical order of being be deficient in any way, 

 then simply mind cannot manifest itself at all, or only in a 

 manner we call defective or abnormal. 



1 Typical presentations of this the now prevalent view may be found, among 

 many other references, in Lotze, Microcosmus ; Darwin, Descent of Man; Ro- 

 manes, Mental Evolution in Man; Wallace, Darwinism; Fiske, Destiny of Man 

 in the Light of His Origin; Drummond, Ascent of Man; Wundt, Human and 

 'Animal Psychology, pp. 5-7 and 440-445 ; James, The Will to Believe, chap, on 

 Reflex Action and Theism. 



