A System of Logic: Ratiocinative and Inductive, 7th Edition, Vol. II
John Stuart Mill · en
§ 8. We have seen in the last chapter that there is a point of
generality at which empirical laws become as certain as laws of nature,
or rather, at which there is no longer any distinction between empirical
laws and laws of nature. As empirical laws approach this point, in other
words, as they rise in their degree of generality, they become more
certain; their universality may be more strongly relied on. For, in the
first place, if they are results of causation (which, even in the class
of uniformities treated of in the present chapter, we never can be
certain that they are not) the more general they are, the greater is
proved to be the space over which the necessary collocations prevail,
and within which no causes exist capable of counteracting the unknown
causes on which the empirical law depends. To say that anything is an
invariable property of some very limited class of objects, is to say
that it invariably accompanies some very numerous and complex group of
distinguishing properties; which, if causation be at all concerned in
the matter, argues a combination of many causes, and therefore a great
liability to counteraction; while the comparatively narrow range of the
observations renders it impossible to predict to what extent unknown
counteracting causes may be distributed throughout nature. But when a
generalization has been found to hold good of a very large proportion of
all things whatever, it is already proved that nearly all the causes
which exist in nature have no power over it; that very few changes in
the combination of causes can effect it; since the greater number of
possible combinations must have already existed in some one or other of
the instances in which it has been found true. If, therefore, any
empirical law is a result of causation, the more general it is, the more
it may be depended on. And even if it be no result of causation, but an
ultimate coexistence, the more general it is, the greater amount of
experience it is derived from, and the greater therefore is the
probability that if exceptions had existed, some would already have
presented themselves.