natural theology proceeds upon the ground that the inference for a
final cause of the structure of the hand and of the valves in the
veins is just as valid now, in individuals produced through natural
generation, as it would have been in the case of the first man,
supernaturally created. Why not, then, just as good even on the
supposition of the descent of men from Chimpanzees and Gorillas, since
those animals possess these same contrivances? Or, to take a more
supposable case: If the argument from structure to design is
convincing when drawn from a particular animal, say a Newfoundland
dog, and is not weakened by the knowledge that this dog came from
similar parents, would it be at all weakened, if, in tracing his
genealogy, it were ascertained that he was a remote descendant of the
mastiff or some other breed, or that both these and other breeds came
(as is suspected) from some wolf? If not, how is the argument for
design in the structure of our particular dog affected by the
supposition that his wolfish progenitor came from a post-tertiary
wolf, perhaps less unlike an existing one than the dog in question is
from some other of the numerous existing races of dogs, and that this
post-tertiary came from an equally or more different tertiary wolf?
And if the argument from structure to design is not invalidated by our
present knowledge that our individual dog was developed from a single
organic cell, how is it invalidated by the supposition of an analogous
natural descent, through a long line of connected forms, from such a
cell, or from some simple animal, existing ages before there were any
dogs? Again, suppose we have two well-known and very decidedly
different animals or plants, A and D, both presenting, in their
structure and in their adaptations to the conditions of existence, as
valid and clear evidence of design as any animal or plant ever
presented: suppose we have now discovered two intermediate species, B
and C, which make up a series with equable differences from A to D. Is