Elements of the philosophy of the human mind. By Dugald Stewart. Rev. and abridged, with critical and explanatory notes, for the use of colleges and schools. By Francis Bowen ...

REASONING AND DEDUCTIVE EVIDENCE. 419
science, where the use of an ambiguous word is impossible, it may
1-e easily conceived how the solution of a problem may be
reduced to something resembling the operation of a mill - the
conditions of the problem, when once translated from the common language into that of algebra, disappearing entirely from
the view; and the subsequent process being almost mechanically
regulated by general rules, till the final result is obtained. In
the latter, the whole of the words about which our reasonings
are conversant, admit, more or less, of defferent shades of meaninug; and it is only by considering attentively the relation in
which they stand to the immediate context, that the precise idea
of the author in any particular instance is to be ascertained.
It these sciences, accordingly, the constant and unremitting exercise of the attention is indispensably necessary, to prevent us, at
every step of our progress, from going astray. In following
any train of reasoning, beyond the circle of the mathematical
sciences, the mind must necessarily carry on, along with the
logical deduction expressed in words, another logical process of
a far nicer and more difficult nature;- t]hat of fxiny, with a
rapidity which escapes our memory, the precise sense of every
word which is ambiguous, by the relation in which it stands to
the general scope of the argument. In proportion as the language of science becomes more and more exact, the difficulty
of this task will be gradually diminished; but let the improvement be carried to any conceivable extent, not one step will have
been gained in accelerating that era, so sanguinely anticipated
by Leibnitz and Condillac, when our reasonings in morals and
politics shall resemble, in their mechanical regularity, and in
their demonstrative certainty, the investigations of algebra. The
improvements which language receives, in consequence of the
progress of knowledge, consisting rather in a more precise distinction and classification of the various meanings of words,
than in a reduction of these meanings in point of number, the
task of mental induction and interpretation may be rendered
more easy and unerring; but the necessity of this task can never
be superseded, till every word which we employ shall be as