, now, how all the phraseology employed in speaking of these
successive generalizations of science is borrowed from the action of
mind. The word _action_ itself has no real significance, except when
applied to the _doings_ of an intelligent agent; we cannot speak of the
doings of matter, as we could if the word _action_ were applicable to it
in any other than a figurative sense. Again, in speaking of the
similarity of facts and the regularity of sequences, we refer them to a
_law_ of nature, just as if they were sentient beings acting under the
will of a sovereign. Parts of pure matter--the chemical elements, for
instance--do not _act_ at all; being brute and inert, it is only by a
strong metaphor that they are said to be subject to law. Again, we
attribute _force_, _power_, &c., to the primitive particles of matter,
and speak of their natural _agencies_. Just so, we talk of _tone_ in
coloring, and of a _heavy_ or _light_ sound; though, of course, in their
proper significance, tone belongs only to sound, and heaviness to
gravitating bodies. These modes of speech are proper enough, if their
figurative character be kept in view; but it is a little too bad, when a
whole scientific theory is made to rest upon a metaphor as its sole
support. _Agency_ is the employment of one intelligent being to act for
another; _force_ and _power_ are applicable only to will; they are
characteristic of volition. It is a violent trope to apply either of
these words to senseless matter. Chemical _affinities_ are spoken of, as
if material elements were united by family ties, and manifested choice,
and affection or aversion.

An obvious corollary from these remarks is, that all _causation_ is an
exertion of mind, and is only figuratively applied to matter. It
necessarily implies power, will, and action. An efficient cause--we are
not speaking now of a mere antecedent--is that which is necessarily
followed by the effect, so that, if it were known, the effect might be
predicted antecedently to all experience. Cicero describes it with
philosophical accuracy. "_Causa ea est, quae id efficit, cujus est
causa._ _Non sic causa intelligi debet, ut quod cuique antecedat, id ei
causa sit; sed quod cuique_ EFFICIENTER _antecedat. Causis enim
efficientibus quamque rem cognitis, posse denique sciri quid futurum
esset._" Now, in the world of matter, we discover nothing but
antecedents and consequents; the former are the mere signs, not the
causes, of the lat