67 



Thus the principle of psychophysical parallelism is estab- 

 lished. This principle states the general fact that "certain 

 changes in the organic, in those nerve and brain processes with 

 which consciousness is associated, are always accompanied by 

 changes in consciousness, and also that this last is a statement 

 which can be converted so that it is also true that all changes 

 in consciousness are accompanied by organic changes in the 

 brain and nerves." 1 There is what Baldwin calls an 'equal 

 continuity' in the two series, when the principle of psycho- 

 physical parallelism is applied in Evolution. 2 "Our theory 

 must explain the inheritance of both physical and mental 

 characters to the same degree." 3 "This principle of parallel- 

 ism assumed, we claim once for all the right to include the re- 

 lation of the two terms, mental and physical, in all circum- 

 stances whatever. * * * On this way of conceiving the scientific 

 enquiry, we may proceed unhampered by the problems which 

 trouble the philosopher. * * * We do not have one series of 

 genetic forms, the mental, evolving under shorthand formulae 

 of its own; and another series, the organic, doing the same 

 thing under different formulae. On the contrary, the two sets 

 of facts really go together in one set of formulae. This is what 

 I am arguing for. * * * When we recognize in places the absence 

 of the facts we should expect apparent breaks in either one 

 of the lines we may resort to the resource of using the 

 corresponding facts from the parallel line at the same level." 4 



The principle of psychophysical parallelism as above 

 stated, taken in itself, would not, however, imply the depend- 

 ence of the mental upon organic phenomena in the same 

 way that the theory of the Associationists implied, for in 

 Baldwin's view, the physical and the psychical are terms of 

 the same formulae. In Baldwin, the significance of the 

 principle of psychophysical parallelism for evolution seems to 

 be that psychological phenomena (as in the case of Spencer) 

 no longer remain beyond the pale of the evolutionistic for- 

 mula, that is, the formula of biological evolution. 



As the organic and nervous structures are rendered ever 

 more and more complex through the operation of the law of 

 natural selection; are determined, that is, by heredity and 

 environment, so the concomitant psychological phenomena 

 must likewise be determined, as both series of phenomena 

 come under the operation of the one law. Both are 'pro- 



'O.C. p. 10. 

 2 Ibid. 



3 O.C. p. 14. 

 4 O.C. p. 15. 



