Logic is a general guide to the discovery of truth, and teaches us
its systematic communication to others. This definition is intended to
combine logic and rhetoric into one system. According to a quotation in
Pinnock's Guide to Knowledge, Locke defined logic as 'that art by which
we rightly use our mental faculties in the discovery and communication
of truth,' a definition, called by the writer, the definition of nature
echoed by genius. There exists a natural connection between logic
and rhetoric. The discovery of truth could avail us little if we were
without the means of communicating it; and it is easy to see that it
would be in vain to possess the means of communicating truth, unless we
had the truth to communicate. Therefore, ingenuity is but ill employed
in separating these mutual departments of learning which nature has
connected together. Besides, the skill of the logician is as serviceable
in the statement of a case, as in arguing it. Arrangement is as much a
matter of logic as ratiocination; and to impress this neglected
truth upon the young inquirer, is one reason for proposing a combined
definition.
The mutual connection of logic and rhetoric is illustrated by the
fact, that the Logic of the Schools is purely a branch of rhetoric. It
consists in putting an argument into 'the most perspicuous form in
which it can be exhibited,'*--i. e., in _communicating_ it in the most
efficient way to others.
* Dr. Whatetly: Anal. Ont., chap. 1, aec. 6, p. 45.
Indeed, Dr. Whately (who makes logic to consist in reasoning) defines
reasoning as _discourse_, and discourse is rhetoric. '_Grammar_,'
says Doherty,' represents the mechanism of letters in forming
words--_Rhemar_, the mechanism of words in forming sentences. We have
_Grammar_ for letters, _Rhemar_ for words, _Logic for arguments_, and
_Rhetoric_ for discourse.' Locke-logic, therefore--i. e., logic in the
sense in which Locke treated it--seems to come nearer the truth, as well
as nearer the common requirement, than the restricted definition of it
by others insisted on.