gan and every part of each animal or plant has been designed to
serve some purpose useful to the animal, and this not only useful at
some past time, but useful now, and for all time to come. He who
believes species to be mutable will see in many organs signs of the
history of the individual, but nothing more. Buffon, as I have said, is
explicit in his denial of final causes in the sense expressed above.
After pointing out that the pig is an animal whose relation to other
animals it is difficult to define, he says:--

"In a word, it is of a nature altogether equivocal and ambiguous, or,
rather, it must appear so to those who believe the hypothetical order of
their own ideas to be the real order of things, and who see nothing in
the infinite chain of existences but a few apparent points to which they
will refer everything.

"But we cannot know Nature by inclosing her action within the narrow
circle of our own thoughts.... Instead of limiting her action, we should
extend it through immensity itself; we should regard nothing as
impossible, but should expect to find all things--supposing that all
things are possible--nay, _are_. Doubtful species, then, irregular
productions, anomalous existences will henceforth no longer surprise us,
and will find their place in the infinite order of things as duly as any
others. They fill up the links of the chain; they form knots and
intermediate points, and also they mark its extremities: they are of
especial value to human intelligence, as providing it with cases in
which Nature, being less in conformity with herself, is taken more
unawares, so that we can recognize singular characters and fleeting
traits which show us that her ends are much more general than are our
own views of those ends, and that, though she does nothing in vain, yet
she does but little with the designs which we ascribe to her."[84]

"The pig," he continues, "is not formed on an original, special, and
perfect type; its type is compounded of that of many other animals. It
has parts which are evidently useless, or which at any rate it cannot
use--such as toes, all the bones of which are perfectly formed but
which are yet of no service to it. Nature then is far from subjecting
herself to final causes in the composition of her creatures. Why should
she not sometimes add superabundant parts, seeing she so often omits
essential ones?" "How many animals are there not which lack sense and
limbs? Why is it considered so nec