Wilson, Douglas, and Nathan D. Wilson. The Rhetoric Companion: A Student's Guide to Power in Persuasion. Moscow, Idaho: Canon, 2011.

Lesson 13, “Syllogisms” pp. 67-70.

Wilson introduces the reader to the world of syllogisms, both categorical and hypothetical. A categorical syllogism is deductive in nature. It will be valid or invalid. If valid, assuming the premises are true, the conclusion is true. Wilson introduces some terminology on p. 67. Of the three statements in a syllogism, two are premises and the other is a conclusion. There are also three terms, which are the categories of the syllogism. In his example, “All P are Q. Some Q are R. Therefore, Some R are P” the terms are P, Q, and R. The “major term” is P, the “minor” term is R. The “middle term” is contained in both premises (Wilson 2011, 67). Without deliberately referring the reader to his prior lesson on the square of opposition, Wilson organizes his syllogism. This one has an A, then an I statement and concludes with an I statement. He also categorizes the syllogism according to its figure - where the middle term is (Wilson 2011, 68). Wilson then gives five rules to test validity, not making it clear, but implying that the rules iwll work for all syllogisms.

Wilson next discusses “mixed hypothetical syllogisms”, observing that there are two kinds which are valid and two which are invalid. He refers readers to his book on logic and leaves the reader now with the necessary basis for rhetorical reasoning. The material was very compressed and not easy to follow. Yet he will move along to deal with various logical fallacies in the next lesson.