# Phil 103 Introduction to Logic

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```					Phil 103: Introduction to Logic
Ryan Hickerson

Solutions to Non-Starred Exercises, CIL 1.2

I.

2. Not an argument. This is a warning.

3. Argument! The premises are: (1) "without freedom of the press our other freedoms
would be immediately threatened," and (2) "freedom of the press provides the
fulcrum for the advancement of new freedoms," and the conclusion is: (3) "Freedom
of the press is the most important of our constitutionally guaranteed freedoms."

5. Not an argument. This is a piece of advice.

6. This is probably not an argument. We're tipped off that this is an illustration by the
phrase "for example." However, this could be what Hurley calls "an argument from
example." Imagine someone who didn't believe the conclusion that "Mosquito bites
are not always the harmless little irritations most of us take them to be." We might
try to convince that person of the contrary by offering the following premise as
evidence: "Some mosquitoes carry West Nile virus, and people who are infected can
become very sick or even die."

8. Explanation. The first and second sentences are the explanans, and the third sentence
is the explanandum.

9. Not an argument. I believe these are good examples of "statements of belief."

11. Argument. The premise is: "Mortality rates for women undergoing early abortions,
where the procedure is legal, appear to be as low as or lower than the rates for normal
childbirth. The conclusion is: "Any interest of the state in protecting the woman
from an inherently hazardous procedure, except when it would be equally dangerous
for her to forgo it, has largely disappeared."

12. This is an expository passage. Notice how the second, third, and fourth sentences all
elaborate upon the basic idea stated in the first.

14. Not an argument. This might be a warning (that's the way I interpret it.) It also
could be an explanation. The explanandum in that case would be: "All of the lions in
the park may be dead within ten years," and the explanans: "the disease is incurable,"
and "the lions have no natural resistance."

15. Argument. The conclusion is the first sentence. The premises are the second
sentence and the third sentence.

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17. Not an argument. These are "loosely associated statements."

18. Explanation. The author of the passage is not trying to convince us that most
businesses include a credit department. The author is trying to explain to us why most
business include a credit department. Consequently, that is the explanandum, and the
statement that "no business concern wants to sell on credit to a customer who will
prove unable or unwilling to pay his or her account" is the explanans. (Consequently,
notice that the word "consequently" isn't always a conclusion indicator word!)

20. Explanation.

21. This is not an argument. This is a joke. But if it were an argument, the conclusion
would be: "Dachshunds are ideal dogs for small children" and the premise would be:
"they are already stretched and pulled to such a length that the child cannot do much
harm."

23. This is not an argument. Perhaps it is an illustration (if the chair-pulling is being
offered as an example of a practical joke), or perhaps it is an explanation (of why the
practical joke is the coarsest form of humor.) Or perhaps it is expository. If none of
those, then it could fall into the category of "loosely associated statements." But it is
definitely not an argument.

24. Not an argument. This is a statement of belief or statement of opinion.

26. Whether or not this is an argument depends upon whether the passage is attempting
to prove, or provide evidence for, the claim that "words are slippery customers." If
the passage attempts to prove that this is so by citing the fact that full meaning doesn't
appear until the word is placed in a context, and even then would depend upon the
listener, speaker, the experience with the language, the knowledge of one another,
etc., and all of those things would constitute "slippery customer," then it is an
argument. But it is more likely that this is an explanation, or an expository passage.

27. This is a report.

29. This is either an explanation, where the explanandum is "many model changes are
not technologically substantive" and the explanans is the businessmen conspiring to
shorten the useful life of their products in order to guarantee replacement sales, or
these are loosely associated statements.

30. Illustration.

32. Explanation.

33. Argument. The first sentence is the conclusion and the second, third, and fourth
sentences are premises. This one might also plausibly be interpreted as an

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explanation, with the first sentence as the explanandum and the second, third, and
fourth sentences as explanans.

35. Illustration.

II.

2. Not an argument.
3. Not an argument.
5. Argument! The conclusion is: opposing obligatory prayer is not deserting god. The
premise is: god wants children to pray to him of their own free will and not because
some legislator forces them to.
6. Not an argument.
8. This is an argument. The conclusion is: We are soulless. The premises are: "Forty-
one million Americans cannot afford health insurance," and "nine people earned more
than \$10 million last year." There's an important suppressed premise in this
argument, however. In order for it to be a good, logically speaking, we must also
grant that "allowing the existence of a massive disparity of wealth makes us soulless."
(And lots of people would deny that, I think.)
9. Argument. The conclusion is the first sentence and the premises are: (1) "If there
were evolutionary advantages to harming one's mate's offspring of a different parent,
then by now there probably wouldn't be loving and generous stepparents around." (2)
I have a loving stepparent. (3) I am a loving stepparent. (4) There are plenty of
loving and generous stepparents around. Notice that there is a little "mini-argument"
embedded in the main argument of this passage. The "mini-argument" concludes (4)
from premises (2) and (3). But then the main argument uses (1) and (4) as premises
for the main conclusion (which is the first sentence of the passage.) Notice also that
premise (1) is a conditional statement.

III.

There are a variety of good, 100 word arguments in support of (or opposed to) the claims
1-10 of this section.

IV.

argument from example: an argument similar to an illustration insofar as an example is
used to attempt to prove the truth of a more general claim
conditional statement: an "if… then…" statement
antecedent: the component statement immediately following the "if" in a conditional
statement
consequent: the component statement immediately following the "then" in a conditional
statement

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sufficient condition: an event such that whenever it occurs, its effect follows
necessary condition: an event that must occur in order for its effect to follow
explanation: an expression that purports to shed light on (or make more intelligible)
some event or phenomenon
explanandum: an event or phenomenon that is being explained
explanans: a statement or group of statements that purports to explain something else
illustration: an expression involving one or more examples that is intended to show what
something means or how it is done
expository passage: discourse that begins with a topic sentence followed by one or more
sentences that develop the topic sentence

V.

1. True.
2. False.
3. False.
4. True.
5. True.
6. True.
7. True.
8. True.
9. True.
10. True.

VI.

2. necessary. If x is a tiger, then x is an animal.
3. sufficient. If one drinks water, then one will quench one's thirst.
5. necessary. If one drinks an expensive bottle of wine, then one pulls the cork. (This
actually isn't true anymore.)
6. sufficient. If one steps on the cat's tail, then one makes the cat yowl.
8. necessary. If one understands a lecture, then one attends to the lecture.
9. sufficient. If one takes a swim in the North Sea, then one cools off.

VII.

(Ryan skipped this section of the assignment!)

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