It were a mere unprofitable dispute about
words, did we entertain and discuss the question, whether the import of
the term "law" might not be so extended as to include under it _powers_,
_properties_, and _causes_, as well as the _rules_ and _conditions_ of
their operation: for, even were this question answered in the
affirmative, there would still be room for a real distinction between
the two, and there could be no reason for saying that the knowledge of
"causes," as distinguished from "laws," is wholly inaccessible to the
human faculties. There is thus a real and important distinction between
"laws" considered simply as general facts, and "causes" considered as
efficient agents; and the two cannot be reduced to the same category,
otherwise than by giving such an extension to the term "law" as shall
make it comprehensive of _causation_; and even then, the distinction
remains between the mere formulas of Science and the actual forces of
Nature. "The laws of Nature," says the sagacious Dr. Reid, "are the
_rules_ according to which the effects are produced, but there must be a
_cause_ which operates according to these rules. The rules of navigation
never navigated a ship; the rules of architecture never built a
house."[190]

It might be shown, were it needful for our present purpose, that the
object of Science is _threefold: first_, to ascertain particular facts;
_secondly_, to reduce these facts under general laws; and, _thirdly_, to
investigate the "causes" by which both _facts_ and _laws_ may be
accounted for. The exclusion of any one of the three would be fatal to
Philosophy as well as Religion; and it is prohibited by the "natural
laws" of the human mind, which has the capacity not only of observing
particular facts, but of comparing and contrasting them so as to deduce
from them a knowledge of general laws, and which is also imbued with an
instinctive and spontaneous tendency to ascribe every change that is
observed to some "power" or "cause" capable of producing such an effect.
It might further be shown, that in every instance a "cause," properly so
called, is a _substance_ or _being_ possessing certain properties or
powers,--properties which may be called, if you will, the "laws" of that
substance, but which necessarily include the idea of _causation_ or
_efficiency_; that in the case of mere physical agency, there must be a
plurality of substances so related as that the one shall act on the
other in certain con