32 THE HISTORY OF CREATION. 



posteriori cannot rightly be placed in opposition, as is 

 usually done. On the contrary, sensuous experience is 

 the original source of all knowledge. For this reason alone, 

 all oui' knowledge is limited, and we can never apprehend 

 the first causes of any phenomena. The force of crystal- 

 lization, the force of gravitation, and chemical affinity 

 remain in themselves just as incomprehensible as do 

 Adaptation and Inheritance. 



Seeing that Darwin's theory explains from a single point 

 of view the totality of all those phenomena of which we 

 have given a brief survey, that it demonstrates one and 

 the same quality of the organism as the active cause in all 

 cases, we must allow that it gives us for the present all 

 that we can desire. Moreover, we have good reason to hope 

 that at some future time we shall learn to explain the first 

 causes at which Darwin has arrived, namely, the properties 

 of Adaptation and Inheritance ; and that we shall succeed in 

 discovering in the composition of albuminous matter certain 

 molecular relations as the remoter, simpler causes of these 

 phenomena. There is indeed no prospect of this in the 

 immediate future, and we content ourselves for the present 

 with the tracing back of organic phenomena to two 

 mysterious properties, just as in the case of Newton's 

 theory we are satisfied with tracing the planetary motions 

 to the force of gravitation, which itself is likewise a mys- 

 tery to us and not cognizable in itself. 



Before commencing our principal task, which is the care- 

 ful discussion of the Doctrine of Descent, and the conse- 

 quences that arise out of it, let us take an historical retro- 

 spect of the most important and most widely spread of those 

 views, which before Darwin men had elaborated concernin^^ 



I 



