All instructional materials copyright, W.D. Godfrey. In the real world, an effective argument may consist of a number of elements that combine to persuade the audience of the soundness of the conclusions.
Logic is a little more particular about what makes a good argument.
It speaks of the validity of a syllogism. It speaks of the proof of a propositional argument. And it speaks of the soundness of an argument which bases its support on probability of truth rather than technical certainty. In the sections on Class Logic and Propositional Logic, we deal with the specific fallacies which may weaken or defeat an argument of these types. An argument may be technically weak and yet effective.