 My own view is that Aristotle’s texts support a somewhat different understanding. He also tells us that dialectical premises differ from demonstrative ones in that the former are questions, whereas the latter are assumptions or assertions: “the demonstrator does not ask, but takes”, he says. This fits most naturally with a view of dialectic as argument directed at another person by question and answer and consequently taking as premises that other person’s concessions. Anyone arguing in this manner will, in order to be successful, have to ask for premises which the interlocutor is liable to accept, and the best way to be successful at that is to have an inventory of acceptable premises, i.e., premises that are in fact acceptable to people of different types.