Wow. Look at this definition! “Now syllogism is a statement [logos] in which, certain things having been posited, something other than the posited necessarily results through what is posited” (100a). We have something—and something else comes in to being from it! Where’s Aristotle’s On Coming to Be and Passing Away when I need it? J
“Apodeixis [logical demonstration] occurs whenever the syllogism is drawn from things that are true and primary or from things that are of the sort as to have taken the first principle of knowledge of them from what is primary and true; but a syllogism is dialectical when drawn from generally accepted opinions” (100a-100b18). Things that are true are persuasive in themselves and by themselves. Opinions, or endoxa, are things that seem right to all people or most people or the wise, meaning most of the wise, or the most well-known as authorities.
Dialectic is useful for 3 purposes: mental training as a method to undertake discussion on any subject, serious conversation that lets us restate what other say to us, and philosophical science, since dialectic enables us to state both sides of an issue and thereby more easily see what is true and what is false.
“We shall possess the method completely when we are in the same situation as in rhetoric and medicine and such faculties: that is, [able] to accomplish what we choose from the available means; for neither will the one with rhetorical skill persuade by every means nor will the doctor heal, but if none of the available means is neglected we shall say that he has knowledge adequately” (101b).
[What exactly is “available means”?]
From Topics Book 1.1-3