In Reply to: Speak rhetorically... posted by Ben on July 11, 2008 at 15:43:
: I would be grateful if someone cold explain meaning and origin of 'speak rhetorically, act in prose'
It's probably presumptuous of me to try to explain someone else's metaphor, especially one that I've never heard or read. But let's try.
Rhetorical speech is intended to keep up the attention and interest of the audience, and more often than not to presuade them of something. It tends, therefore, to rely on colorful modifiers, figures of speech, and the use of the hortatory, conditions and subjunctive moods of verbs. When you speak, you can speak in clouds of possibilities and fanciful suppositions.
When you act, you act in the indicative mood. Every act is a decision taken, a done deal, a fact, even if the action is to tell a lie. Prose does not all have to be in the indicative mood, but rhetoric does sometimes tend toward the poetical and imaginary. But I don't care for the metaphor precisely because it requires figuring it out. It relies on a comparison of dissimilar things.
As to the origin of this saying, I've never heard it, and Google can't find anyone else who has, either, except you.