Syllogisms

University of Phoenix Material

Syllogisms, Logic, and Emotion

Part I: Syllogisms

TO BE A VALID SYLLOGISM, THE CONCLUSION MUST BE PROVEN BY THE REASONS. CAREFULLY STUDY THE FOLLOWING SYLLOGISMS AND DECIDE IF THEY ARE VALID OR INVALID:

1. All zebras are striped animals. No zebras are polar bears. Therefore, no polar bears are striped animals.

2. All clowns are funny individuals. Some sad people are clowns. Therefore, some sad people are funny individuals.

3. Some sticky substances are yucky things. All taffy is a sticky substance. Therefore, some taffy is a yucky thing.

4. All items made of gold are expensive items. Some rings are items made of gold. Therefore, some rings are expensive items.

5. All flies are winged creatures. All butterflies are winged creatures. Therefore, all butterflies are flies.

The following are examples of syllogistic arguments that are missing the conclusions. Study the reasons carefully and complete the syllogism with the conclusion that logically follows.

6. All fragile things are breakable things. Some glasses are fragile things. Therefore,

7. All mammals are warm-blooded animals. All whales are mammals. Therefore,

8. All books are things with pages. Some books are mysteries. Therefore,

9. All flowers are pretty objects. All pansies are flowers. Therefore,

10. No animals are plants. All sheep are animals. Therefore,

Reprinted with permission of the authors Elizabeth T. Tice, PhD, and Jay Gallagher, PhD.

Hypothetical Syllogism—Conditional Argument

Hypothetical syllogisms, or conditional arguments, can have two valid and two invalid structures. The two valid structures are affirming the antecedent, or modus ponens, and denying the consequent, or modus tollens. The two invalid structures, or fallacies, are denying the antecedent and affirming the consequent. Determine if the following arguments are valid or invalid and what form they take. The first one has been completed for you....