44 Darwin, and after Darwin. 
display a progressive advance of organization from 
below upwards. 
Now we have seen that although this tree-like 
arrangement of natural groups was as suggestive as 
anything could well be of all the forms of life being 
bound together by the ties of genetic relationship, 
such was not the inference which was drawn from it. 
Dominated by the theory of special creation, natu- 
ralists either regarded the resemblance of type subor- 
dinate to type as expressive of divine ideals mani- 
fested in such creation, or else contented themselves 
with investigating the facts without venturing to 
speculate upon their philosophical import. But even 
those naturalists who abstained from committing 
themselves’ to any theory of archetypal plans, did 
not doubt that facts so innumerable and so uni- 
versal must have been due to some one co-ordi- 
nating principle—that, even though they were not 
able to suggest what it was, there must have been 
some hidden bond of connexion running through the 
whole of organic nature. Now, as we have seen, it is 
manifest to evolutionists that this hidden bond can be 
nothing else than heredity ; and, therefore, that these 
earlier naturalists, although they did not know what 
they were doing, were really tracing the lines of 
genetic descent as revealed by degrees of structural 
resemblance,— that the arboresent grouping of organic 
forms which their labours led them to begin, and in 
large measure to execute, was in fact a family tree of 
life. 
Here, then, is the substance of the argument from 
classification. The mere fact that all organic nature 
thus incontestably lends itself to a natural arrange- 
