The Philosophj of Evolution. 3^' 



THE PHILOSOPHY OF EVOLUTION. 



BY PROF. S. H. CARPENTER, LL. D., UNIVERSITY OF WISCONSIN. 



The intellectual processes of a rational being must proceed' 

 according to some law. They cannot succeed each other at 

 hap-hazard. The notion of rationality is conditioned upon this 

 regular procedure; if this be wanting, the essential character 

 of rational action is wanting. But to say that rational processes 

 are determined by law, and conditioned upon a regular proce- 

 dure, is simply to assert that the steps in ratiocination are so 

 related to each other that the relation of each to every other 

 may be determined by the application of the law — the differ- 

 ence between any two steps being analogous to the difference 

 between any other two. The astronomer determines the orbit 

 of a planet from three observations, because he thereby deter- 

 mines the law of variation between these points ; from which 

 he assumes that this law will be constant, presenting a series 

 of terms each differentiated accoiding the series of differ 

 ences already determined. 



Applying the same principle to mental phenomena, wc may 

 determine the law of intellectual action. Thoughts are dis- 

 criminated by the presence or absence of certain attributes. 

 At one extreme we find the summum genus, comprising the 

 fewest possible attributes distinguishing an idea; at the other 

 extreme we find the individual, comprising any number of at- 

 tributes. Between these two extremes we find a regular ser- 

 ies of intermediate terms. The movement of an idea from the 

 general to the individual is like the motion of a planet through 

 one-half of its orbit; while the return movement from the in- 

 dividual to the general, corresponds to the motion of the planet 

 over the remaining half of its orbit The same law governs 

 both movements and unites the two halves of the orbit into a 



