n, the same disturbing force probably acts as a modifying cause
in many other cases which no one will call exceptions.

Thus if it were stated to be a law of nature, that all heavy bodies fall
to the ground, it would probably be said that the resistance of the
atmosphere, which prevents a balloon from falling, constitutes the
balloon an exception to that pretended law of nature. But the real law
is, that all heavy bodies _tend_ to fall; and to this there is no
exception, not even the sun and moon; for even they, as every astronomer
knows, tend towards the earth, with a force exactly equal to that with
which the earth tends towards them. The resistance of the atmosphere
might, in the particular case of the balloon, from a misapprehension of
what the law of gravitation is, be said to _prevail_ over the law; but
its disturbing effect is quite as real in every other case, since though
it does not prevent, it retards the fall of all bodies whatever. The
rule, and the so-called exception, do not divide the cases between them;
each of them is a comprehensive rule extending to all cases. To call one
of these concurrent principles an exception to the other, is
superficial, and contrary to the correct principles of nomenclature and
arrangement. An effect of precisely the same kind, and arising from the
same cause, ought not to be placed in two different categories, merely
as there does or does not exist another cause preponderating over it.

It is only in art, as distinguished from science, that we can with
propriety speak of exceptions. Art, the immediate end of which is
practice, has nothing to do with causes, except as the means of bringing
about effects. However heterogeneous the causes, it carries the effects
of them all into one single reckoning, and according as the sum-total is
_plus_ or _minus_, according as it falls above or below a certain line,
Art says, Do this, or Abstain from doing it. The exception does not run
by insensible degrees into the rule, like what are called exceptions in
science. In a question of practice it frequently happens that a certain
thing is either fit to be done, or fit to be altogether abstained from,
there being no medium. If, in the majority of cases, it is fit to be
done, that is made the rule. When a case subsequently occurs in which
the thing ought not to be done, an entirely new leaf is turned over; the
rule is now done with, and dismissed: a new train of ideas is introduced,
between wh