on the ethics of discourse

(for the purposes of this post, i will be using a very primitive notion of right and wrong)

how okay is it to use as much rhetoric, outside of logic, in order to argue for something in the course of some discourse?

my gut reaction is to say that it's not okay at all. but there seems to be a very big difference, though, if you consider certain types of rhetorical devices (mostly the aesthetically inclined ones) than if you consider certain rhetorical methods that directly contradict logic (affirming the consequent, or whatever.)

let's take some concrete examples. using anaphora is a well known method for capturing the attention of the audience, especially if spoken. This seems harmless, and it sure does sound good.

on the other hand, affirming the consequent is a straightforwardly false in deductive logic. and unless used in a provisional and very specifically delineated discussion (where it might be justifiable under the guise of an abductive inference), it would be either a formal fallacy (to some uninformed speaker) or an intentional manipulation (where it would be used as a rhetorical device). either way, some shady stuff is going on and there very clearly see that something bad is going on here.

but even upon reconsideration of the previous example, of the aesthetically-motivated rhetoric, is there more to these devices than meets the eye? could it be that these rhetorical methods are distracting from the point of the message? in some way, is discourse supposed to be just presenting the facts in a logical manner without the hooplah and smoke and mirrors that any rhetorical device other than the clear argumentation only cold hard logic can offer?

no way, that can't be right either. i need to unstiffen my requirements for an acceptable discourse, as those aesthetically motivated rhetorical devices add a lot to some speeches, they help deliver the message more than hinder it. such as in dr. king's "i have a dream" speech, which is in english language anthologies nationwide.

could it be that any of these methods are acceptable if the GOAL of the discourse if justified, or in any case "right" by some other standard? this is a question i'll leave for another time