A balanced sentence is a sentence made up of two parts that are roughly equal in length, importance, and grammatical structure, as in the advertising slogan for KFC: "Buy a bucket of chicken and have a barrel of fun." In contrast with a loose sentence, a balanced sentence is composed of a paired construction on the level of the clause.
Although not necessarily indicative of meaning by themselves, Thomas Kane notes in "The New Oxford Guide to Writing" that "balanced and parallel constructions do reinforce and enrich meaning." Because the words that comprise the sentence are the true conveyers of intent, then, Kane intends balanced sentences to be understood as modifiers to rhetoric.
Balanced sentences can come in a variety of forms. For instance, a balanced sentence that makes a contrast is called antithesis. Additionally, balanced sentences are considered rhetorical devices because they often sound unnatural to the ear, elevating the perceived intellect of the speaker.
How Balanced Sentences Reinforce Meaning
Most linguists agree that the primary utility of a well-stated balanced sentence is to provide perspective for the intended audience, though the concept does not convey meaning by itself. Rather, the optimum grammar tools to convey meaning are, of course, words.
In John Peck and Martin Coyle's "The Student's Guide to Writing: Spelling, Punctuation, and Grammar," the authors describe the elements of balanced sentences: "Their symmetry and neatness of structure… lend an air of being carefully thought out and weighed." Using this type of balance and symmetry can be particularly helpful for speechwriters and politicians to emphasize their points.
Typically, though, balanced sentenced are considered to be a more conversational and, therefore, are most often found in poetic prose, persuasive speeches, and verbal communication than in academic publications.
Balanced Sentences as Rhetorical Devices
Malcolm Peet and David Robinson describe balanced sentences as a type of rhetorical device in their 1992 book "Leading Questions," and Robert J Connors notes in "Composition-Rhetoric: Backgrounds, Theory, and Pedagogy" that they developed in rhetorical theory later in its practice.
Peet and Robinson use Oscar Wilde's quote "children begin by loving their parents; after a time they judge them; rarely, if ever, do they forgive them" to express balanced sentences as unnatural to the ear, "used to impress, to suggest 'wisdom' or 'polish,' because they contain two contrasting and 'balanced' elements." In other words, it presents a duality of ideas in order to convince the listener - or in some cases reader - that the speaker or writer is being especially explicit in his or her meaning and intent.
Although first used by the Greeks, Connors notes that balanced sentences aren't presented clearly in classical rhetoric, and often confused with antithesis - which is a different type of balanced sentence. Academics, Edward Everett Hale, Jr. notes, do not often use the form, as this form is "rather an artificial form," conveying a "natural style" to prose.