Rhetoric - the theory and principles concerned with the effective use of language or the theory and practice of eloquence, both written and oral. It consists of the rules that govern all prose composition or speech designed to influence the judgment or feelings of people, but is only loosely connected with specific details of mechanics, grammar, etc.; it is concerned with a consideration of the fundamental principles according to which oratorical discourses are composed: invention, arrangement, style, memory, and delivery.
The term is from the Greek rhetorike or rhetor, meaning “an orator,” especially a professional one.
The actual founder of rhetoric as a science is said to be Corax of Syracuse in 465 B.C., while Homer is considered the Father of Oratory. To the ancient Greeks, rhetoric was essential for argumentation and oratory. By the medieval era, it became one of the trivium of The Seven Liberal Arts (the other two were grammar and logic) taught at universities. According to Aristotelian theory, rhetoric was a way of organizing material for the presentation of the truth. Socrates, conversely, considered it a superficial art.
Rhetoric was used by Nestor, Odysseus, and, in Homer’s Iliad, Achilles. Satan makes use of rhetoric in Paradise Lost when, in the form of a serpent, he attempts to persuade Eve that eating the forbidden fruit will not kill her:
“ye shall not die: How should ye? By the fruit? It gives you life
To knowledge; by the threatener? look on mee,
mee who have touch’d and tasted,
yet both lives.
And life more perfect have attained than fate
Book IX: lines 685-690