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
These are the uses of syllogism, as a mode of verifying any given
argument. Its ulterior uses, as respects the general course of our
intellectual operations, hardly require illustration, being in fact the
acknowledged uses of general language. They amount substantially to
this, that the inductions may be made once for all: a single careful
interrogation of experience may suffice, and the result may be
registered in the form of a general proposition, which is committed to
memory or to writing, and from which afterwards we have only to
syllogize. The particulars of our experiments may then be dismissed from
the memory, in which it would be impossible to retain so great a
multitude of details; while the knowledge which those details afforded
for future use, and which would otherwise be lost as soon as the
observations were forgotten, or as their record became too bulky for
reference, is retained in a commodious and immediately available shape
by means of general language.
Against this advantage is to be set the countervailing inconvenience,
that inferences originally made on insufficient evidence, become
consecrated, and, as it were, hardened into general maxims; and the mind
cleaves to them from habit, after it has outgrown any liability to be
misled by similar fallacious appearances if they were now for the first
time presented; but having forgotten the particulars, it does not think
of revising its own former decision. An inevitable drawback, which,
however considerable in itself, forms evidently but a small set-off
against the immense benefits of general language.
The use of the syllogism is in truth no other than the use of general
propositions in reasoning. We _can_ reason without them; in simple and
obvious cases we habitually do so; minds of great sagacity can do it in
cases not simple and obvious, provided their experience supplies them
with instances essentially similar to every combination of circumstances
likely to arise. But other minds, and the same minds where they have not
the same pre-eminent advantages of personal experience, are quite
helpless without the aid of general propositions, wherever the case
presents the smallest complication; and if we made no general
propositions, few persons would get much beyond those simple inferences
which are drawn by the more intelligent of the brutes. Though not
necessary to reasoning, general propositions are necessary to any
considerable progress in reasoning. It is, therefore, natural and
indispensable to separate the process of investigation into two parts;
and obtain general formulæ for determining what inferences may be drawn,
before the occasion arises for drawing the inferences. The work of
drawing them is then that of applying the formulæ; and the rules of
syllogism are a system of securities for the correctness of the
application.