OF THE UNITY OF THOUGHT. 695 



On the other side Spencer recognised, what Comte 

 did not, the importance of the ideas of environment and 

 adaptation put forward by some of Comte's contem- 

 poraries. Eeference to these was to be found likewise 

 in von Baer's writings. 



In trying to solve the philosophical problem as he 

 denned it, viz., the unification of knowledge, Spencer 

 describes his special scheme of evolution in the following 

 words : " The processes everywhere in antagonism, and 

 everywhere gaining now a temporary and now a more or 

 less permanent triumph the one over the other, we call 

 Evolution and Dissolution. Evolution under its simplest 

 and most general aspect is the integration of matter and 

 concomitant dissipation of motion ; while Dissolution is 

 the absorption of motion and concomitant disintegration 

 of matter." 



He had before established two principles which he 

 termed respectively the " indestructibility of matter " 

 and the " continuity of motion." To these he added two 

 other principles : the " persistence of force " and the 

 " rhythm of motion." He then goes on to explain that 

 his use of the term Evolution is not identical with other 

 accepted meanings of the term. " While," he says, " we 

 shall by Dissolution everywhere mean the process tacitly 

 implied by its ordinary meaning the absorption of 

 motion and disintegration of matter we shall every- 

 where mean by Evolution the process which is always 

 an integration of matter and dissipation of motion, but 

 which ... is in most cases much more than this." 



From this definition of his highest principle we see 

 that the biologist Spencer, in trying to find the ultimate 



