selection has been satisfactorily established as a cause adequate to
account for all these effects. Given the facts of heredity, variation,
struggle for existence, and the consequent survival of the fittest, what
follows? Why that each step in the prolonged and gradual development of
the eye was brought about by the elimination of all the less adapted
structures in any given generation, i.e. the selection of all the better
adapted to perpetuate the improvement by heredity. Will the teleologist
maintain that this selective process is itself indicative of special
design? If so, it appears to me that he is logically bound to maintain
that the long line of seaweed, the shells, the stones and the little
heap of garnet sand upon the sea-coast are all equally indicative of
special design. The general laws relating to specific gravity are at
least of as much importance in the economy of nature as are the general
laws relating to specific differentiation; and in each illustration
alike we find the result of the operation of known physical causes to be
that of selection. If it should be argued in reply that the selection in
the one case is obviously purposeless, while in the other it is as
obviously purposive, I answer that this is pure assumption. It is
perhaps not too much to say that every geological formation on the face
of the globe is either wholly or in part due to the selective influence
of specific gravity, and who shall say that the construction of the
earth's crust is a less important matter in the general scheme of things
(if there is such a scheme) than is the evolution of an eye? Or who
shall say that because we see an apparently intentional adaptation of
means to ends as the result of selection in the case of the eye, there
is no intention served by the result of selection in the case of the
sea-weeds, stones, sand, mud? For anything that we can know to the
contrary, the supposed intelligence may take a greater delight in the
latter than in the former process.