A System of Logic: Ratiocinative and Inductive, 7th Edition, Vol. I — John Stuart Mill — John Shaqi
A System of Logic: Ratiocinative and Inductive, 7th Edition, Vol. I
John Stuart Mill · en
The statement, that the uniformity of the course of nature is the
ultimate major premise in all cases of induction, may be thought to
require some explanation. The immediate major premise in every inductive
argument, it certainly is not. Of that, Archbishop Whately's must be
held to be the correct account. The induction, "John, Peter, &c. are
mortal, therefore all mankind are mortal," may, as he justly says, be
thrown into a syllogism by prefixing as a major premise (what is at any
rate a necessary condition of the validity of the argument) namely, that
what is true of John, Peter, &c. is true of all mankind. But how came we
by this major premise? It is not self-evident; nay, in all cases of
unwarranted generalization, it is not true. How, then, is it arrived at?
Necessarily either by induction or ratiocination; and if by induction,
the process, like all other inductive arguments, may be thrown into the
form of a syllogism. This previous syllogism it is, therefore, necessary
to construct. There is, in the long run, only one possible construction.
The real proof that what is true of John, Peter, &c. is true of all
mankind, can only be, that a different supposition would be inconsistent
with the uniformity which we know to exist in the course of nature.
Whether there would be this inconsistency or not, may be a matter of
long and delicate inquiry; but unless there would, we have no sufficient
ground for the major of the inductive syllogism. It hence appears, that
if we throw the whole course of any inductive argument into a series of
syllogisms, we shall arrive by more or fewer steps at an ultimate
syllogism, which will have for its major premise the principle, or
axiom, of the uniformity of the course of nature.[10]
It was not to be expected that in the case of this axiom, any more than
of other axioms, there should be unanimity among thinkers with respect
to the grounds on which it is to be received as true. I have already
stated that I regard it as itself a generalization from experience.
Others hold it to be a principle which, antecedently to any verification
by experience, we are compelled by the constitution of our thinking
faculty to assume as true. Having so recently, and at so much length,
combated a similar doctrine as applied to the axioms of mathematics, by
arguments which are in a great measure applicable to the present case, I
shall defer the more particular discussion of this controverted point in
regard to the fundamental axiom of induction, until a more advanced
period of our inquiry.[11] At present it is of more importance to
understand thoroughly the import of the axiom itself. For the
proposition, that the course of nature is uniform, possesses rather the
brevity suitable to popular, than the precision requisite in
philosophical language: its terms require to be explained, and a
stricter than their ordinary signification given to them, before the
truth of the assertion can be admitted.