Discussion Questions

I. Validity and Counterexample Method
(1) Explaining the difference between true, valid, and sound syllogisms.
(2) Describe how the counterexample method for testing the validity of syllogisms can be very helpful in everyday life.

II. Evaluating Validity: Rules 1 and 2
(1) Explain the difference between “terminological” and “qualitative” rules of validity.
(2) Explain how equivocation plays a part in the construction of invalid syllogisms (avoid using a pun to make your point).
(3) Explain why the inferential process of a syllogism is disrupted when there are four terms. (Hint: You may want to use the analogy of conduction provided in lesson 8.2 to help you clarify your answers.)
(4) Explain why the inferential process is disrupted in a syllogism when the middle term appears in the conclusion. (You may want to again refer to the conduction example provided in lesson 8.2.)

III. Evaluating Validity: Rules 3 and 4
(1) Explain the concept of “distribution” as it relates to valid syllogism construction. Cover:
(a) Why do we consider both the subject and predicate terms of an E statement to be distributed?
(b) Why do we consider only the subject term of an A statement to be distributed?
(c) Why do we consider neither the subject nor the predicate terms of an I statement to be distributed?
(d) Why do we consider only the predicate term of an O statement to be distributed?
(2) Think back to chapter 6 (Relationships of Equivalence) and reconsider how obversion, conversion, and contraposition are affected by issues of distribution of terms. Explain why certain propositions can and cannot be converted in equivalent statements in light of distribution.

IV. Evaluating Validity: Qualitative Rules
(1) In your own words explain why:
(a) no conclusion can follow two negative premises, and why there must always be at least one affirmative premise in a syllogism.
(b) if both of the premises are affirmative, the conclusion must be affirmative.
(c) if either premise is negative, the conclusion must be negative.