6 Darwin's Predecessors 
the mutability of species, and he was far ahead of his age in his 
suggestion of what we now call a Station of Experimental Evolution. 
Leibnitz discusses in so many words how the species of animals may 
be changed and how intermediate species may once have linked those 
that now seem discontinuous. “All natura] orders of beings present 
but a single chain ”....All advances by degrees in Nature, and nothing 
by leaps.” Similar evolutionist statements are to be found in the 
works of the other “philosophers,” to whom Prof. Osborn refers, who 
were, indeed, more scientific than the naturalists of their day. It 
must be borne in mind that the general idea of organic evolution— 
that the present is the child of the past—is in great part just the 
idea of human history projected upon the natural world, differentiated 
by the qualification that the continuous “Becoming” has been 
wrought out by forces inherent in the organisms themselves and 
in their environment. 
A reference to Kant? should come in historical order after Buffon, 
with whose writings he was acquainted, but he seems, along with 
Herder and Schelling, to be best regarded as the culmination of the 
evolutionist philosophers—of those at least who interested themselves 
in scientific problems. In a famous passage he speaks of “the agree- 
ment of so many kinds of animals in a certain common plan of 
structure”...an “analogy of forms” which “strengthens the sup- 
position that they have an actual blood-relationship, due to derivation 
from a common parent.” He speaks of “the great Family of creatures, 
for as a Family we must conceive it, if the above-mentioned con- 
tinuous and connected relationship has a real foundation.” Prof. 
Osborn alludes to the scientific caution which led Kant, biology being 
what it was, to refuse to entertain the hope “that a Newton may one 
day arise even to make the production of a blade of grass comprehen- 
sible, according to natural laws ordained by no intention.” As Prof. 
Haeckel finely observes, Darwin rose up as Kant’s Newton” 
The scientific renaissance brought a wealth of fresh impressions 
and some freedom from the tyranny of tradition, and the twofold 
stimulus stirred the speculative activity of a great variety of men 
from old Claude Duret of Moulins, of whose weird transformism 
1 See Brock, +“ Di y ie.” Be 
1p, l= “Pa el an wa Daet eater 
2 Mr Alfred Russel Wallace writes: ‘‘We claim for Darwin that he is the Newton of 
natural history, and that, just so surely as that the discovery and demonstration by 
raneete of the law of gravitation established order in place of chaos and laid a sure 
oundation for all future study of the starry heavens, so surely has Darwin, by his discovery 
