There is another line of thought which has to do with living organisms,
but which I shall beg leave to anticipate and bring in here at the close
of this chapter, since it follows as a direct corollary from the law of
the Conservation of Energy. Indeed, we might even term it the biological
aspect of that law.
As we have seen, we can neither create energy nor destroy it; though we
can _lose it_,--so far as this earth is concerned. The vast fund of
energy that daily comes streaming to us from the sun is transmuted back
and forth in a thousand ways, though little by little it is dissipated
off into space, and we are dependent upon a fresh supply from the ever
replenished fountain.
Just so, though in a somewhat idealistic sense, is it with what we may
term vital energy. Cells, organisms, even whole races, are subject to
degeneration and decay. They cannot acquire higher powers, though they
may gradually lose what they already have; as Bateson has recently told
us that whatever evolution there is must be by loss and not by gain.
Water very easily runs down hill; but cannot go up hill in and of
itself. Just so with the types of organic life. It was not merely an
idle sneer of the witty Frenchman, that science has not yet explained
how an ancestor can transmit what he has not got himself. He cannot
always transmit all that he himself actually possesses of nature's
gifts. Vitality becomes lowered, and the type degenerates. Weismann has
emphasized this idea in his doctrine of "panmixia," or the withdrawal of
selection, which always results in degeneration. Selection, artificial
or natural, may serve to counteract this universal tendency of organic
life, but only approximately. As Sir William Dawson says, "All things
left to themselves tend to degenerate." Little by little the endowment
of vitality bestowed upon our world at the beginning has, like radiant
energy, been returned to God who gave it; but, unlike the case of
radiant energy, the Creator has not established any regular source of
vital supply from without, no elixir of life for organic nature in
general. There is no longer within easy reach a tree of life from which
we may pluck and eat and live forever. And as the individual grows old
and dies, so do species and even whole tribes degenerate and become
extinct.
"From scarpéd cliff and quarried stone
She cries, 'A thousand types are gone.'"
The glorious flood of vitality, so prodigally lavished upon our world in
the beginning, has been ebbing lower and lower; and the theory of
organic nature steadily advancing from the lower to the higher is
manifestly just as puerile as the old hope of creating energy by a
perpetual-motion machine,--and a mistake of precisely the same nature.
Both are contradicted by the magnificent law of the Conservation of
Energy, which, as we have said, is only the scientific expression of the
Scriptural statement that Creation is completed, so far as our world is
concerned; though, as the "wages of sin," death has been decreed upon
the individual, and degeneration more or less marked upon every organic
type. The fossils of the past, as well as our own experience within the
historic period, confirm the view already arrived at on other grounds
that _Creation is a completed work and is not now going on_; and the
universal testimony from organic nature is that degeneration and decay
have marked the history of every living form. Just as the individual
grows old and dies, so do species degenerate and become extinct.