ooked for causes, and
found them, when it was very young; but, up to the time of David Hume,
no one had shown what causality meant, and the explanation which he
offered is now rejected by modern science, as definitely as it is
rejected by philosophy. Meantime, while philosophy is still engaged in
exposing the fallacies of the theory of association as held by Hume,
science has gone beyond this category altogether; it is now establishing
a theory of the conservation of energy, which supplants the law of
causality by tracing it into a deeper law of nature.

There is some force in this argument, but it cuts both ways. For, even
if it be admitted that the category was successfully applied in the
past, it is also admitted that it was applied without being understood;
and it cannot now be questioned that the philosophers were right in
rejecting it as the final explanation of the relation of objects to each
other, and in pointing to other and higher connecting ideas. And this
consideration should go some way towards convincing evolutionists that,
though they may be able successfully to apply the idea of development to
particular facts, this does not guarantee the soundness of their view of
it as an instrument of thought, or of the nature of the final results
which it is destined to achieve. Hence, without any disparagement to the
new extension which science has received by the use of this new idea, it
may be maintained that the ordinary view of its tendency and mission is
erroneous.

"The prevailing method of explaining the world," says Professor Caird,
"may be described as an attempt to level 'downwards.' The doctrine of
development, interpreted as that idea usually is interpreted, supports
this view, as making it necessary to trace back higher and more complex
to lower or simpler forms of being; for the most obvious way of
accomplishing this task is to show analytically that there is really
nothing more in the former than in the latter."[A] "Divorced from
matter," asks Professor Tyndall, "where is life to be found? Whatever
our _faith_ may say our _knowledge_ shows them to be indissolubly
joined. Every meal we eat, and every cup we drink, illustrates the
mysterious _control of Mind by Matter_. Trace the line of life backwards
and see it approaching more and more to what we call the _purely
physical condition_."[B] And then, rising to the height of his subject,
or even above it, he proclaims, "By an intellectual necessity I c