For the sake of clearness I have assumed that the physical causes with
which we are already acquainted are sufficient to explain the observed
phenomena of organic nature. But it clearly makes no difference whether
or not this assumption is conceded, provided we allow that the observed
phenomena are all due to physical causes of some kind, be they known or
unknown. That is to say, in whatever measure we exclude the hypothesis
of the direct or immediate intervention of the Deity in organic nature
(miracle), in that measure we are reducing the evidence of design in
organic nature to precisely the same logical position as that which is
occupied by the evidence of design in inorganic nature. Hence I conceive
that Mill has shown a singular want of penetration where, after
observing with reference to natural selection, 'creative forethought is
not absolutely the only link by which the origin of the wonderful
mechanism of the eye may be connected with the fact of sight,' he goes
on to say, 'leaving this remarkable speculation (i.e. that of natural
selection) to whatever fate the progress of discovery may have in store
for it, in the present state of knowledge the adaptations in nature
afford a large balance of probability in favour of creation by
intelligence.' I say this passage seems to me to show a singular want of
penetration, and I say so because it appears to argue that the issue
lies between the hypothesis of special design and the hypothesis of
natural selection. But it does not do so. The issue really lies between
special design and natural causes. Survival of the fittest is one of
these causes which has been suggested, and shown by a large accumulation
of evidence to be probably a true cause. But even if it were to be
disproved as a cause, the real argumentative position of teleology would
not thereby be effected, unless we were to conclude that there can be no
other causes of a secondary or physical kind concerned in the
production of the observed adaptations.