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 practice, indeed, is recommended by considerations far too obvious
to require a formal justification. Logic is a portion of the Art of
Thinking: Language is evidently, and by the admission of all
philosophers, one of the principal instruments or helps of thought; and
any imperfection in the instrument, or in the mode of employing it, is
confessedly liable, still more than in almost any other art, to confuse
and impede the process, and destroy all ground of confidence in the
result. For a mind not previously versed in the meaning and right use of
the various kinds of words, to attempt the study of methods of
philosophizing, would be as if some one should attempt to become an
astronomical observer, having never learned to adjust the focal distance
of his optical instruments so as to see distinctly.
Since Reasoning, or Inference, the principal subject of logic, is an
operation which usually takes place by means of words, and in
complicated cases can take place in no other way; those who have not a
thorough insight into the signification and purposes of words, will be
under chances, amounting almost to certainty, of reasoning or inferring
incorrectly. And logicians have generally felt that unless, in the very
first stage, they removed this source of error; unless they taught their
pupil to put away the glasses which distort the object, and to use
those which are adapted to his purpose in such a manner as to assist,
not perplex, his vision; he would not be in a condition to practise the
remaining part of their discipline with any prospect of advantage.
Therefore it is that an inquiry into language, so far as is needful to
guard against the errors to which it gives rise, has at all times been
deemed a necessary preliminary to the study of logic.
But there is another reason, of a still more fundamental nature, why the
import of words should be the earliest subject of the logician's
consideration: because without it he cannot examine into the import of
Propositions. Now this is a subject which stands on the very threshold
of the science of logic.