The Evolution of Mind. 2 1 9 



evolution of material forms, it is necessary for Mr. 

 Spencer to obtain a unit of intelligence analogous to 

 the chemical and physiological units which play 

 so important a part in his doctrine of inorganic 

 and organic evolution. This " unit of conscious- 

 ness " is indispensable to his hypothesis. Without 

 it, he can no more build up a mind than he could 

 build up an organism without his physiological units, 

 We shall examine this unit of consciousness some- 

 what closely. 



"There may be a single primordial element of 

 consciousness, and the countless kinds of consciousness 

 may be produced by the compounding of this element 

 with itself, and recompouiiding of its compounds with 

 one another in higher and higher degrees ; so produc- 

 ing increased multiplicity, variety, and complexity 

 ... It is possible then may we not say probable ? 

 that something of the same order as that which we call 

 a nervous shock is the ultimate unit of consciousness; 

 and that unlikeness among our feelings results from 

 unlike modes of integration of the ultimate unit. . . . 

 Our typical case of musical sound will exhibit the 



agreement Here the nerve pulses and the 



pulses of feeling clearly answer to one another ; and 

 it can scarcely be doubted that they do so through- 

 out." " Mind is certainly in some cases, and probably 

 in all, resolvable into nervous shocks ; and these 

 nervous shocks answer to the waves of molecular 

 motion that traverse nerves and nerve centres." . 



