CATEGORICAL SYLLOGISMS

1. For the mood and figure below, write out the syllogism it describes. Hint: Start with the figure, and lay out the positions of S, M, and P, then use the mood to fill in the quantifier and copula for that proposition.

IEO-2

2. Put the following syllogism into standard form (remember to put the major premise first), and then identify the mood and figure.

Some promilitary advertisements are not propaganda, because some of them are truthful, and no truthful advertisement is propaganda.

3. Put the following syllogism into standard form, and then identify the mood and figure. Then use the rules for testing to determine whether the argument is valid or invalid. If it is invalid, state all the rules it violates.

Some countries whose people need AIDS medications have illegitimate governments, and no legitimate government neglects the needs of its poor population. So some countries that neglect the needs of their poor are countries whose people need AIDS medication.

4. For the following syllogism, diagram the premises and the conclusion to determine whether the syllogism is valid. Describe your combined premise Venn diagram & conclusion Venn diagram using the numbered 7 quadrant Venn structure on p. 198.

EXTRA CREDIT: evaluate using the rules too. Do your evaluations agree?

Some M are P

All S are M

_____________________

Some S are not P

5. Use Venn diagrams to determine whether the following syllogism is valid. Describe your combined premise Venn diagram & conclusion Venn diagram using the numbered 7 quadrant Venn structure on p. 198.

EXTRA CREDIT: evaluate using the rules too. Do your evaluations agree?

No P is M

All S are M

_____________________

Some S are P

6. Put the following statement into standard form as a categorical proposition, and determine whether the subject and predicate terms are distributed.

Some restaurants that serve liquor do not have a license.

INDUCTIVE GENERALIZATIONS

7. Evaluate the following generalization inductively, drawing on your own experience. If you think you don’t know enough to tell whether it is true or false, identify the kind of evidence you would need in order to decide. In each case, indicate how each of the three rules for generalizing would guide your reasoning.

Heroes in tragic drama always have a fatal flaw.

8. Analyze the following inductive argument. First identify the conclusion. Is it positive or negative? Which factor is being said to be (or not to be) the cause of which effect? Then identify the method used to support the conclusion: agreement, difference, or the joint method. Use the standard schema to represent the cases. Finally, look for problems in the use of the methods.

In a controlled study, three cars of different types, of different ages, and from different manufacturers were tested for gas mileage before and after a tune-up. In every case, mileage improved after the tuneup, which shows that a well-tuned engine affects fuel efficiency.

9. Analyze the following inductive argument. First identify the conclusion. Which factor is being said to be the case of which effect? Then determine whether the method used to support the conclusion is concomitant variations or residues.

Scientific data show that the death rate from lung cancer increases with the amount that people smoke. For those who smoke up to a pack a day, the rate is six times that for nonsmokers; for those smoking over a pack a day, the rate is about 12 times higher. Smoking is clearly a cause of lung cancer.

10. Analyze the following inductive argument. First identify the conclusion. Which factor is said to be the case of which effect? Then determine which of the five methods is used to support the conclusion: agreement, difference, joint method, concomitant variations or residues.

It is not true that suicide bombings are always the result of mental illness, despite the seeming insanity of the act. For every suicide bomber who meets the clinical criteria for insanity, there are others who share the same political cause and religious beliefs but are not insane.