Syllogisms and Logic

University of Phoenix Material

Syllogisms and Logic

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.

valid

2. All clowns are funny individuals.

Some sad people are clowns.

Therefore, some sad people are funny individuals.

invalid

3. Some sticky substances are yucky things.

All taffy is a sticky substance.

Therefore, some taffy is a yucky thing.

valid

4. All items made of gold are expensive items.

Some rings are items made of gold.

Therefore, some rings are expensive items.

valid

5. All flies are winged creatures.

All butterflies are winged creatures.

Therefore, all butterflies are flies.

invalid

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

1. All fragile things are breakable things.

Some glasses are fragile things.

Therefore all glasses are breakable things

6. All mammals are warm-blooded animals.

All whales are mammals.

Therefore all whales are warm-blooded animals

7. All books are things with pages.

Some books are mysteries.

Therefore some mysteries are things with pages

8. All flowers are pretty objects.

All pansies are flowers.

Therefore all pansies are pretty objects

9. No animals are plants.

All sheep are animals.

Therefore no sheep are plants.

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

PART II: LOGIC & EMOTION QUESTIONS:

There are two ways to make an argument: through inductive and deductive reasoning. Answer the questions below.

Deductive Argument

1. What makes an argument...