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.