THE COMPOSITION OF MIND 



shocks answering to that sim^\t physical pulsation 

 which is the ultimate unit of nervous action. By 

 the manifold and diverse compounding of myr- 

 iads of such primitive psychical shocks, accord- 

 ing to the slight structural differences of differ- 

 ent nerves, are formed innumerable elementary 

 sensations, which appear to be generically differ- 

 ent ; just as aquafortis and laughing-gas, which 

 seem generically different, yet differ really only 

 in the proportions of nitrogen and oxygen which 

 compose them. By a similar differential com- 

 pounding of these elementary sensations, we 

 get complex sensations of blueness and redness, 

 warmth, pressure, sweetness, roughness, and of 

 various kinds of timbre and degrees of pitch. 

 Carrying still farther the same process of differ- 

 entiation and integration, we rise step by step to 

 perceptions of greater and greater complexity, to 

 conscious classifications, and to reasoning in its 

 various forms, from the crude inferences of the 

 child, barbarian, or boor, to the subtle and indi- 

 rect combinations of the artist and the scientific 

 discoverer. Thus amid all their endless diver- 

 sities we discern, though dimly, a fundamental 

 unity of composition throughout all orders of psy- 

 chical activity, from the highest to the lowest.^ 



^ [For a later criticism of this Taine-Spencer theory of the 

 composition of mind, which might well have modified Fiske's 

 acceptance of the theory had he rewritten this chapter, see 

 James, Principles of Psychology y vol. i. pp. 1 5 1 sqq. ] 



191 



