64 COSMIC PHILOSOPHY. [n. ii. 



now agreed upon, there may be framed an outline of a 

 tolerably complete classification of agencies. Let us reduce 

 to a common form of expression the agencies contemplated 

 in this and in the two preceding chapters. 



Considered in the widest sense, the processes which we 

 have seen to cooperate in the evolution of organisms are all 

 processes of equilibration or adjustment. From the dyna- 

 mical point of view, as has been shown in previous chapters, 

 an organism is a complex aggregate of matter, in which per- 

 manent structural and functional differentiations and inte- 

 grations are rendered possible by the fact that it continually 

 receives about as much motion as it expends. Now a state 

 in which expended motion is continually supplied from 

 without, is called a state of dependent moving eq^uilibrium. 

 In other words, it is a state in which every change in the 

 distribution of external forces must be met by a change in 

 the distribution of internal forces, in order that the equili- 

 brium may be preserved. This is the case with every 

 organism. Its life is a perpetual balancing of external 

 forces by internal forces. And the complete accomplishment 

 of this end requires also that there shall be a continuous 

 internal equilibration, — a perpetual balancing of forces opera- 

 tive in the different parts of the organism. Thus the career 

 of an organism, or of a group of organisms, consists of two 

 kinds of equilibration, which we may briefly designate as 

 external and internal equilibration. And a moment's con- 

 sideration will show us that each of these kinds of equilibra- 

 tion may be either direct or indirect. The adjustment of a 

 group of organisms to changing external circumstances is 

 effected partly by such direct adaptations as we have above 

 considered, partly by the destruction of all those members of 

 the group which do not become directly adapted. In this 

 latter way equilibrium is maintained indirectly ; and natural 

 selection, or survival of the fittest, may be accurately cha- 

 racterized as " indirect equilibration." Turning now to the 



