Properly speaking, then, the religious theory of final causes does not
explain any of the phenomena of Nature: it merely re-states the
phenomena as observed--or, if we prefer so to say, it is itself an
ultimate and universal explanation of all possible phenomena taken
collectively. For it must be admitted that behind all possible
explanations of a scientific kind, there lies a great inexplicable,
which just because of its ultimate character, cannot be merged into
anything further--that is to say, cannot be explained. 'It is what it
is,' is all that we can say of it: 'I am that I am' is all that it could
say of itself. And it is in referring phenomena to this inexplicable
source of physical causation that the theory of Religion essentially
consists. The theory of Science, on the other hand, consists in the
assumption that there is always a practically endless chain of physical
causation to investigate--i.e. an endless series of phenomena to be
explained. So that, if we define the process of explanation as the
process of referring observed phenomena to their adequate causes, we may
say that Religion, by the aid of a general theory of things in the
postulation of an intelligent First Cause, furnishes to her own
satisfaction an ultimate explanation of the universe as a whole, and
therefore is not concerned with any of those proximate explanations or
discovery of second causes, which form the exclusive subject-matter of
Science. In other words, we recur to the definitions already stated, to
the effect that Religion is a department of thought having, as such,
exclusive reference to the Ultimate, while Science is a department of
thought having, as such, no less exclusive reference to the Proximate.
When these two departments of thought overlap, interference results, and
we find confusion. Therefore it was that when the religious theory of
final causes intruded upon the field of scientific inquiry, it was
passing beyond its logical domain; and seeking to arrogate the function
of explaining this or that phenomenon _in detail_, it ceased to be a