…for rhetorical discourse, in their estimation, stands higher than dialectic, and that first interpretation is the one favored by their earlier, more exacting authorities. Neither rhetorical nor dialectical argument, they say, is required to be non-demonstrative, just as it is no condition of a demonstrative argument that it never be used to address the populace or to refute an opponent. Indeed, when a demonstrative premise is also well-known, it serves both demonstration and rhetoric; when a dialectical premise turns out to be demonstrative, it is fit for demonstration as well as for dialectic. Likewise, if a proposition is proven and at the same time famous—being conceded by the disputant—it is suitable for demonstration, rhetoric, and dialectic alike.
Poetic discourse, by contrast, is of another order, for its purpose is to move the soul, not to impart either knowledge or even conjecture; hence it is not counted with the previous three. Moreover, rhetorical arguments are intended for the general public and therefore rely on propositions that are well-known among them, even if merely probable; should those propositions be certain, so much the better—there is no rule that they must fall short of certainty. Dialectical argument, on the other hand, is directed to specific interlocutors; once they grant the premises, the dialectician’s goal is achieved even if those premises are not commonly known.
As for the sophistical, it is the deceptive semblance—falsehood dressed in the garb of truth. It is mentioned only to expose its corruption, for no one is permitted to advance it in earnest: it is a lie in the guise of veracity, falsehood in the form of right. Its citation serves merely to identify it and to exercise minds in dissolving sophistical doubts.
One of their sharp-witted men, eager to link their path with that of the prophets, may even say that the three divisions—demonstration, dialectic, and rhetoric—are alluded to in the Almighty’s words:
“Call to the way of your Lord with wisdom and good admonition, and argue with them in the manner that is best.”
The philosophers’ discourse concerning the prophets—peace be upon them—then proceeds: they maintain that what the prophets brought is a form of rhetorical address aimed at the masses, not a disclosure of realities. This, they say, pertains to practical matters; even in the theoretical realm they sometimes relegate its first principles not to demonstrative proofs but to well-known propositions, such as knowledge of the goodness of justice and the repugnance of