Nothing can be more hopeless than to attempt to explain this similarity
of pattern in members of the same class, by utility or by the doctrine
of final causes. The hopelessness of the attempt has been expressly
admitted by Owen in his most interesting work on the "Nature of Limbs."
On the ordinary view of the independent creation of each being, we can
only say that so it is; that it has pleased the Creator to construct all
the animals and plants in each great class on a uniform plan; but this
is not a scientific explanation.