THE NATURE OF THE SOUL. 93 



basis of all psychic activity, without which it is incon- 

 ceivable, the provisional name of " psychoplasrn "; 

 and for this good reason — that chemical analysis 

 proves it to be a body of the group we call proto- 

 plasmic bodies, the albuminoid carbon-combinations 

 which are at the root of all vital processes. In the 

 higher animals, which have a nervous system and 

 sense-organs, " neuroplasm," the nerve-material, has 

 been differentiated out of psychoplasrn. Our con- 

 ception is, in this sense, materialistic. It is at the 

 same time empirical and naturalistic, for our scientific 

 experience has never yet taught us the existence of 

 forces that can dispense with a material substratum, 

 or of a spiritual world over and above the realm of 

 nature. 



Like all other natural phenomena, the psychic pro- 

 cesses are subject to the supreme, all-ruling law of 

 substance ; not even in this province is there a single 

 exception to this highest cosmological law (compare 

 chap. xii.). The phenomena of the lowly psychic 

 life of the unicellular protist and the plant, and of the 

 lowest animal forms — their irritability, their reflex 

 movements, their sensitiveness and instinct of self- 

 preservation — are directly determined by physiological 

 action in the protoplasm of their cells — that is, by 

 physical and chemical changes which are partly due 

 to heredity and partly to adaptation. And we must 

 say just the same of the higher psychic activity of the 

 higher animals and man, of the formation of ideas 

 and concepts, of the marvellous phenomena of reason 

 and consciousness ; for the latter have been phylo- 

 genetically evolved from the former, and it is merely 

 a higher degree of integration or centralisation, of 

 association or combination of functions which were 



