Topic 6 Reading Exercises from:

Copi, Irving M.Introduction to Logic, 14th Edition. Routledge.

6.1 INSTRUCTIONS

Rewrite each of the following syllogisms in standard form, and name its mood and figure.(Procedure:first, identify the conclusion; second, note its predicate term, which is the major term of the syllogism; third, identify the major premise, which is the premise containing the major term; fourth, verify that the other premise is the minor premise by checking to see that it contains the minor term, which is the subject term of the conclusion; fifth, rewrite the argument in standard formmajor premise first, minor premise second, conclusion last; sixth, name the mood and figure of the syllogism.)

Example Problem

No nuclear-powered submarines are commercial vessels, so no warships are commercial vessels, because all nuclear-powered submarines are warships.

Example Solution

Step 1.	The conclusion is "No warships are commercial vessels."
Step 2.	"Commercial vessels" is the predicate term of this conclusion and is therefore the major term of the syllogism.
Step 3.	The major premise, the premise that contains this term, is "No nuclear-powered submarines are commercial vessels."
Step 4.	The remaining premise, "All nuclear-powered submarines are warships," is indeed the minor premise, because it does contain the subject term of the conclusion, "warships."
Step 5.	In standard form this syllogism is written thus:
	No nuclear-powered submarines are commercial vessels. All nuclear-powered submarines are warships. Therefore no warships are commercial vessels.
Step 6.	The three propositions in this syllogism are, in order,E, A, andE. The middle term, "nuclear-powered submarines," is the subject term of both premises, so the syllogism is in thethirdfigure. The mood and figure of the syllogism therefore areEAE-3.

PROBLEMS

2.Some evergreens are objects of worship, because all fir trees are evergreens, and some objects of worship are fir trees.

3.All artificial satellites are important scientific achievements; therefore some important scientific achievements are not U.S. inventions, inasmuch as some artificial satellites are not U.S. inventions.

4.No television stars are certified public accountants, but all certified public accountants are people of good business sense; it follows that no television stars are people of good business sense.

5.Some conservatives are not advocates of high tariff rates, because all advocates of high tariff rates are Republicans, and some Republicans are not conservatives.

6.All CD players are delicate mechanisms, but no delicate mechanisms are suitable toys for children; consequently, no CD players are suitable toys for children.

7.All juvenile delinquents are maladjusted individuals, and some juvenile delinquents are products of broken homes; hence some maladjusted individuals are products of broken homes.

8.No stubborn individuals who never admit a mistake are good teachers, so, because some well-informed people are stubborn individuals who never admit a mistake, some good teachers are not well-informed people.

9.All proteins are organic compounds, hence all enzymes are proteins, as all enzymes are organic compounds.

10.No sports cars are vehicles intended to be driven at moderate speeds, but all automobiles designed for family use are vehicles intended to be driven at moderate speeds, from which it follows that no sports cars are automobiles designed for family use.

6.3 INSTRUCTIONS

Write out each of the following syllogistic forms, using S and P as the subject and predicate terms of the conclusion, and M as the middle term. (Refer to the chart of the four syllogistic figures, if necessary, on p. 235.)

Example Problem

AEE-1

Example Solution

We are told that this syllogism is in the first figure, and therefore the middle term, M, is the subject term of the major premise and the predicate term of the minor premise. (See chart on p. 235.) The conclusion of the syllogism is an Eproposition and therefore reads: No S is P. The first (major) premise (which contains the predicate term of the conclusion) is an A proposition, and therefore reads: All M is P. The second (minor) premise (which contains the subject term of the conclusion) is an E proposition and therefore reads: No S is M. This syllogism therefore reads as follows:

All M is P.

No S is M.

Therefore no S is P.

PROBLEMS

2.EIO-2

3.OAO-3

4.AOO-4

5.EIO-4

INSTRUCTIONS

Put each of the following syllogisms into standard form, name its mood and figure:

PROBLEMS

1.Some reformers are fanatics, so some idealists are fanatics, because all reformers are idealists.

2.Some philosophers are mathematicians; hence some scientists are philosophers, because all scientists are mathematicians.

3.Some mammals are not horses, for no horses are centaurs, and all centaurs are mammals.

4.Some neurotics are not parasites, but all criminals are parasites; it follows that some neurotics are not criminals.

5.All underwater craft are submarines; therefore no submarines are pleasure vessels, because no pleasure vessels are underwater craft.

6.4INSTRUCTIONS

Identify the rule that is broken by any of the following syllogisms that are invalid, and name the fallacy that is committed:

Example Problem

All chocolate clairs are fattening foods, because all chocolate clairs are rich desserts, and some fattening foods are not rich desserts.

Example Solution

In this syllogism the conclusion is affirmative ("all chocolate clairs are fattening foods"), while one of the premises is negative ("some fattening foods are not rich desserts"). The syllogism therefore is invalid, violating the rule that if either premise is negative the conclusion must also be negative, thereby committing the fallacy of drawing an affirmative conclusion from a negative premise.

PROBLEMS

2.All inventors are people who see new patterns in familiar things, so all inventors are eccentrics, because all eccentrics are people who see new patterns in familiar things.

3.Some snakes are not dangerous animals, but all snakes are reptiles, therefore some dangerous animals are not reptiles.

4.Some foods that contain iron are toxic substances, for all fish containing mercury are foods that contain iron, and all fish containing mercury are toxic substances.

5.All opponents of basic economic and political changes are outspoken critics of the liberal leaders of Congress, and all right-wing extremists are opponents of basic economic and political changes. It follows that all outspoken critics of the liberal leaders of Congress are right-wing extremists.

6.No writers of lewd and sensational articles are honest and decent citizens, but some journalists are not writers of lewd and sensational articles; consequently, some journalists are honest and decent citizens.

7.All supporters of popular government are democrats, so all supporters of popular government are opponents of the Republican Party, inasmuch as all Democrats are opponents of the Republican Party.

8.No coal-tar derivatives are nourishing foods, because all artificial dyes are coal-tar derivatives, and no artificial dyes are nourishing foods.

9.No coal-tar derivatives are nourishing foods, because no coal-tar derivatives are natural grain products, and all natural grain products are nourishing foods.

10.All people who live in London are people who drink tea, and all people who drink tea are people who like it. We may conclude, then, that all people who live in London are people who like it.