THE BEGINNINGS OF LIFE. 121 



motion; and the change from a concentrated per- 

 ceptible state to a diffused imperceptible state is 

 an absorption of motion and concomitant disintegra- 

 tion of matter. These are truisms. Constituent parts 

 cannot aggregate without losing some of their relative 

 motion, and they cannot separate without more relative 

 motion being given to them ' .' To the former process 

 Mr. Spencer applies the term Evolution-, and to the 

 latter Dissolution. Both processes are constantly being 

 carried on, either separately or conjointly, in all exist- 

 ences whatsoever. 



But there are two modes of Evolution which we 

 shall do well to distinguish in their most divergent 

 aspects, although they are connected with one another 

 by almost insensible gradations. 



When the forces at work are strong and tend to 

 produce rapid aggregation, as in the case of the for- 

 mation of a Crystal, we have to do simply with an 

 ^integration of matter and concomitant dissipation 

 of motion;' but when integration takes place more 

 slowly, 'either because the quantity of motion con- 

 tained in the aggregate is relatively great ; or because 

 though the quantity of motion which each part pos- 

 sesses is not relatively great, the large size of the 



^ ' First Principles,' 2nd ed. p. 284. 



2 This use of the word * Evolution,' although arbitrary and open to 

 many objections, was rendered inevitable by previous use and custom. 

 As Mr. Spencer says : — ' The antithetical word Involution would much 

 more truly express the nature of the process ' (lop. cit., p. 285). 



\ 



