What is the rhetorical term for PREMISE of argument?

A course of reasoning aimed at demonstrating truth or falsehood. Argument is one of the traditionalmodes of discourse. Adjective: argumentative.

Daniel J. O'Keefe, a professor of communication and persuasion theory, has distinguished two senses of argument. Put simply, "Argument1, the first sense, is a thing people make, as when an editorialist argues that some public policy is wrong. Argument2 is a kind of interaction people have, as when two friends argue aboutwhere to have lunch.

(For the specialized use of this term in language studies, see Argument [Linguistics].)So argument1 comes close to the ancient rhetorical notion of argument, while argument2legitimates the modern interactional research"

(quoted by Dale Hample in "A Third Perspective on Argument." Philosophy and Rhetoric, 1985).