Introductory . i 7 



species. But now that a very reasonable explanation 

 of the origin of species has been offered by science, it 

 is but in accordance with all previous historical 

 analogies that many minds should prove themselves 

 unable all at once to adjust themselves to the new 

 ideaS; and thus still linger about the more venerable 

 ideas of supernaturalism. But we are now in pos- 

 session of so many of these historical analogies, that 

 all minds with any instincts of science in their 

 composition have grown to distrust, on merely ante- 

 cedent grounds, any explanation which embodies a 

 miraculous element. Such minds have grown to 

 regard all these explanations as mere expressions of 

 our own ignorance of natural causation; or, in other 

 words, they have come to regard it as an a priori 

 truth that nature is everywhere uniform in respect of 

 method or causation ; that the reign of law universal ; 

 the principle of continuity ubiquitous. 



Now, it must be obvious to any mind which has 

 adopted this attitude of thought, that the scientific 

 theory of natural descent is recommended by an 

 overwhelming weight of antecedent presumption, as 

 against the dogmatic theory of supernatural design. 



To begin with, we must remember that the fact of 

 evolution — or, which is the same thing, the fact of 

 continui.y in natural causation — has now been un- 

 questionably proved in so many other and analogous 

 departments of nature, that to suppose any interruption 

 of this method as between species and species becomes, 

 on grounds of such analogy alone, well-nigh incredible. 

 For example, it is now a matter of demonstrated fact 

 that throughout the range of inorganic nature the 

 principles of evolution have obtained. It is no longer 



