CHAPTER XIII. 



HUMAN POPULATION IN THE FUTURE. 



371. Any further evolution in the most-highly evolved 

 of terrestrial beings, Man, must be of the same nature as 

 evolution in general. Structurally considered, it may consist 

 in greater integration, or greater differentiation, or both 

 augmented bulk, or increased heterogeneity and definiteness, 

 or a combination of the two. Functionally considered, it 

 may consist in a larger sum of actions, or more multiplied 

 varieties of actions, or both a larger amount of sensible and 

 insensible motion generated, or motions more numerous in 

 kind and more intricate and exact in co-ordination, or 

 motions that are greater alike in quantity, complexity, and 

 precision. 



Expressing the change in terms of that more special 

 evolution displayed by organisms ; we may say that it must 

 be one which further adapts the moving equilibrium of 

 organic actions. As it was pointed out in First Principles, 

 133, " the maintenance of such a moving equilibrium, re- 

 quires the habitual genesis of internal forces corresponding 

 in number, directions, and amounts to the external incident 

 forces as many inner functions, single or combined, as there 

 are single or combined outer actions to be met." And it 

 was also pointed out that " the structural complexity accom- 

 panying functional equilibration, is definable as one in which 

 there are as many specialized parts as are cnpable, separately 



