CATEGORICAL PROPOSITIONS

1. Identify the subject and predicate terms, the quality, and the quantity. Then name the form (A, E, I, O).

Some works of art are not beautiful things.

2. Put the following proposition into standard form. Identify the subject and predicate terms, the quality, the quantity, and name the form (A, E, I, O).

Not a single doctor can figure out what’s wrong with my son.

3. For the following pair of propositions, given that the first one is true, determine whether the second is true, false or undetermined, in accordance with the traditional square of opposition.

A. No S is P.

B. Some S is P.

4. Put the following statement into standard form as a categorical proposition. Then construct a Venn diagram for the proposition — or describe one. Diagram interlocking circles S and P.

Some stores don’t charge high prices for trendy clothes.

5. State the converse of the following proposition, and indicate whether the proposition and its converse are equivalent.

All geniuses struggle with madness.

6. State the obverse of the following proposition. Make sure you use genuinely complementary terms.

No sighting of a UFO is a thing that has been confirmed.

7. State the contrapositive of the following proposition. Determine whether the contrapositive is the equivalent of the original.

All S are non-P.

9. Additional Exercises D #5

State the logical relationship that exists between the following pair of propositions. Then state whether the second one is equivalent to the first.

A. Some people are persons unlucky in love.

B. Some people are not persons lucky in love.

10. Additional Exercises D #6

For each pair of propositions, use Venn diagrams to determine whether they are equivalent. In both diagrams, the Scircle represents the subject of the first proposition and the P circle represents the predicate of the first proposition.

A. None of my acquaintances is in trouble with the law.

B. No one who is in trouble with the law is an acquaintance of mine.