Introductory. 1 
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@ priord 
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- 
reel proved in so many other and analogous 
of this ened as Debveen 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 zzorganic nature the 
principles of evolution have obtained. It is no longer 
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