In the present day, however, the province of Rhetoric, in the widest acceptation that would reckoned admissible, comprehends all "Composition in Pros… - Richard Whately

No one complains of the rules of Grammar as fettering Language; because it is understood that correct use is not founded on Grammar, but Grammar on correct use. A just system of Logic or of Rhetoric is analogous, in this respect, to Grammar..

Cicero is hardly to be reckoned … for he delighted so much more in the practice, than in the theory, of his art, that he is perpetually drawn off from the rigid philosophical analysis of its principles, into discursive declamations, always eloquent indeed, and often highly interesting, but adverse to regularity of system, and frequently as unsatisfactory to the practical student as to the Philosopher.

He that is not aware of his ignorance, will be only misled by his knowledge.