This paper considers discourse models of knowledge and use and social problem solving that revive the tradition of dialectical reasoning (the broader term) or rhetoric, i.e., the art of using language, in speaking or writing, to convince others that something is true, right, or better. Discourse models of knowledge use allow taking the context-bound, tentative nature of research knowledge, as well as the beliefs and purposes of clients and patrons, into consideration. Problems derive from a failure to meet such empirical preconditions (e.g., social organization of discourse), and from the fact that such empirical preconditions pre-suppose concepts of knowledge with an egalitarian rather than an authoritative cast. Where people do not appeal to such standards, discourse may simply reinforce existing inequalities. Social reform and educational change depend in part on a rejection of the dialectical tradition insofar as it involves the language of persuasion rather than that of experiments. These problems are illustrated by looking at pre-suppositions and limitations of argument as a discourse model of knowledge use. In conclusion, argument is contrasted with conversation, and conversation itself is considered as a concept of education. (Author/JD)