Aristotle has just finished discussing his division of propositions and problems into three categories by subject. He continues his discussion of the tools of argument by discussing how to use propositions in arguments. He does this in Topics, Book 1.
For purposes of philosophy we must treat of these things according to their truth, but for dialectic only with an eye to opinion. All propositions should be taken in their most universal form- then, the one should be made into many. E.g. The knowledge of opposites is the same- next, The knowledge of contraries is the same, and of relative terms. In the same way these should again be divided, as long as division is possible, e.g. the knowledge of good and evil, of white and black, of cold and hot. Likewise also in other cases.
When using dialectic for philosophical reasons we should argue based on the truth of our starting propositions. When we are using dialectic for the other purposes, we should only consider how convincing our argument is. All propositions should be extended to the most universal form possible. For example, contraries is a genus that includes opposites. So The knowledge of contraries is the same is a more universal proposition than The knowledge of opposites is the same. The same is true with the relative terms and contrary terms. We should also take that most general form and divide it into many very specific forms. We should try to be as specific as possible. Using the previous example, we should pick specific examples of the knowledge of relative terms. These would include a knowledge of good and evil, white and black and hot and cold. We should do this with all propositions we are going to use in argument.
This first claim of Aristotles creates numerous problems. I suggest rejecting it. All dialectic arguments should aim at the truth rather than being convincing. It promotes bad intellectual habits that contribute to problems in society.
Next, Aristotle will discuss what the second tool is.