The Province of Rhetoric

All worthy discourse aims at producing some change in the mind addressed. It may be a change of knowledge, or instruction ; a change of opinions, or conviction ; a change of disposition, or persuasion ; or a change of the passing emotion for its own sake, or mere entertainment. Whatever this change be, it is produced by ideas. These ideas are effective in pro¬ducing the change only when they are assimilated to the dominant ideas of the mind addressed. The rhet¬orical process extends farther than the mere presenta¬tion of ideas ; it is complete only when those ideas are referred to the preexisting ideas of the person addressed in such a manner that they will effect the desired change. All mental changes take place in accordance with certain laws. As an art, Rhetoric communicates ideas according to these laws ; as a science, it discovers and establishes these laws. Rhetoric is, therefore, the science of the laws of effective discourse.
Discourse aims to produce a change (1) in the mind, (2) by means of ideas, 3) expressed through language. The science of producing mental changes must include an account of the laws of the mind, the idea, and the form. The laws of mind which affect the change of ideas, the peculiar characteristics of the main classes of ideas, the special properties of language as a medium of expression, all belong to the sphere of Rhetoric.