Philosophy 130: Quiz 3        Name:

Part 1: Key Concepts

Match the terms in the center column with the best fitting characterization or definition from the right.  Answer in the leftmost column. (1 pt. each)

1. _B_

2. _A_

3. _J_

4. _M_

5. _C_

6. _D_  

7. _K_

8. _F_

9. _H_

10. _G_

11. _L_  

12. _E_

13. _I_

1.  affirming the antecedent

2.  affirming the consequent

3.  categorical statement

4.  DeMorgan's Law 

5.  denying the antecedent

6. denying the consequent

7.  either-or dilemma 

8.  fallacy of accident

9.  fallacy of affirming an alternative

10.  process of elimination

11.  singular categorical statement 

12.  transitivity of implication

16.  universal statement

A. invalid deductive form as follows: If P then Q; Q; :. P.
B.  valid argument form -- aka modus ponens -- as follows: If P then Q; P; :.Q.
C.  invalid argument form as follows: If P then Q; not P; :. not Q.
D.  valid argument form -- aka modus tollens -- as follows: If P then Q; not Q; :. not P.
E. valid argument form -- aka hypothetical syllogism -- as follows: If P then Q; if Q then R; :. If P then R.
F. fallacy committed when an argument uses a conditional that generally holds given secondary assumptions that are false in the case in question. 
G. valid argument form aka disjunctive syllogism: P or Q; not P; :. Q.

H.  invalid argument form as follows: P or Q; P; :. not Q.

I. statement with a term like all, none, anything, or nothing.   All cats have whiskers, for example. 
J. statement of the form All F are G, No F are G, Some F are G, or Some F are not G.
K. valid deductive form such as follows: P or Q; if P then R; if Q then R; :. R.
L.  statement of the form A is F, or A is not F predicating class membership or exclusion of a particular individual.  Socrates was wise, for example.

M.  valid deductive form such as follows: Neither P nor Q; :. Not P and not Q.

 

Part 2: Multiple Choice: choose the best answer & write the letter of the answer on the left.

 

  1. Suppose P is certainly true and about Q you can’t tell: how should you evaluate P and Q?

    1. Certainly true.
    2. Probably true.
    3. Can’t tell.
    4. Probably false.

 

  1. Suppose P is certainly true and about Q you can’t tell: how should you evaluate P or Q?

    1. Certainly true.
    2. Probably true.
    3. Can’t tell.
    4. Certainly false.

  2. Suppose P is certainly true and about Q you can’t tell: how should you evaluate If P then Q?

    1. Certainly true.
    2. Can’t tell.
    3. Probably false.
    4. Certainly false.

  3. Suppose P is certainly true and Q is certainly false: how should you evaluate P and Q?

    1. Certainly true.
    2. Certainly false.
    3. Can’t tell.
    4. Probably false.

 

  1. Which of the following categorical syllogisms are valid.

    1. Some F are G; no G are H; some F are not H.
    2. No F are G; some G are not H; some F are H.
    3. All F are G; no G are H; some F are H.
    4. All of the Above.

 

  1. Suppose P is certainly true and Q is certainly false: how should you evaluate if P then Q?

    1. Certainly true.
    2. Certainly false.
    3. Can’t tell.
    4. Probably false.

  2. Suppose you can’t tell about P and you can’t tell about Q: how should you evaluate P and Q?

    1. Probably true.
    2. Probably false.
    3. Can’t tell.
    4. Certainly false.

  3.  Suppose you can’t tell about P and you can’t tell about Q: how should you evaluate P or Q?

    1. Probably true.
    2. Probably false.
    3. Can’t tell.
    4. Certainly true.

  4. Which of the following immediate inferences are invalid?

 

    1. Some F are G; :. Some G are F
    2. No F are G; :. No G are F
    3. Some F are not G; :. Not all F are G
    4. All F are G; :. All G are F

Name:

2.  SIMPLE ARGUMENTS: Clarify one of the following using the standard clarifying format.  Then evaluate following the standard format for evaluation.  (8 pts.)   DO ONE ONLY!

1.  “Although these textbooks purport to be a universal guide to learning of great worth and importance, there is a single clue that points to another direction.  In the six years I taught in city and county schools, no one ever stole a textbook.  (HINT: implicit if-then bridge.) EXERCISES 11j:5

CLARIFICATION
1.  If these textbooks were universal guides to learning of great worth and importance someone would have stolen one in six years.
2. No one has stolen one in six years.
:.
C. These textbooks aren’t universal guides to learning of great worth and importance.

TRUTH
1. Probably true.  Reasonable objection: Thieves usually favor things that have monetary worth.  I reply: six years is a long time.
2. Almost certainly true: he speaks with authority.
LOGIC: Valid by modus tollens: If P then Q; not Q; :. not P
SOUNDESS: Probably sound {(.7*.95) = MHO}

3.  “If each man had a definite set of rules of conduct by which he regulated his life he would be no better than a machine.  But there are no such rules.  So men cannot be machines.”  EXERCISES 11k:3

CLARIFICATION
1.  If men had definite set of rules by they regulated their lives they’d be machines.
2.  Men don’t have definite sets of rules by which they regulate their lives.
:.
C. Men are not machines. 

TRUTH
1. Certainly true: if by rules we mean rote (computable) procedures.
2. Can’t tell: certainly no one consciously follows any such set of rules but the hypothesis that the brain is a computer is widely accepted; our brains compute unconsciously, they say.

LOGIC: Invalid: it denies the antecedent: If P then Q; not P; :. Not Q
SOUNDNESS: Certainly unsound since it’s invalid.

3.  Leroy’s argument. (HINT: Implicit premise)



Alternative clarification
1. All times are times I do something or don’t.
2. All times I do something are times when what I do is wrong
3. All times I don’t do something are when I’m wrong.
:.
C. All times are times I am wrong or what I’m doing is wrong.

CLARIFICATION
[1. Either I do something or I don’t.]
2. If I do something it’s wrong.
3. If I don’t do something I’m wrong.
:.
C. Either I do wrong or I’m wrong.
TRUTH
1. Certainly true by the law of excluded middle.
2. Certainly false: nobody always does wrong
3. Certainly false: certainly false; not always.
LOGIC: Valid dilemma: P or Q; If P then R; If R then S; :. R or S. 
SOUNDNESS: Certainly unsound due to the certainly false premises.
CONVERSATIONAL RELEVANCE: Leroy is exaggerating to make the point that Loretta’s expectations are excessive.

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3.  COMPLEX ARGUMENTS: Clarify one of the following using the standard clarifying format.  Then evaluate following the standard format for evaluation.  (10 pts.)  DO ONE ONLY!

1.  If former Federal Emergency Management Agency (FEMA) director Mike Brown knew about the people stranded at the New Orleans Convention Center and didn’t order their immediate evacuation, then he was uncaring.  If he didn’t know about them he was incompetent.  Either way, he shouldn’t have been in charge of an agency like FEMA.  (HINT: Implicit premise)  

CLARIFICATION
[1. Either M.B. knew or M.B. didn’t know.]
2. If M.B. knew he was uncaring.
3. If M.B. didn’t know he was incompetent.
:.
4. Either M.B. was uncaring or incompetent.
[5. If someone is incompetent or uncaring they shouldn’t be in charge of an agency like FEMA.]
:. C. M.B. shouldn’t have been in charge of an agency like FEMA

TRUTH TO 4
1. Certainly true by the law of excluded middle.
2. Almost certainly true: he was supposedly in charge and it wouldn’t have been that difficult to evacuate them according to all reports.
3. Certainly true: everyone else knew – it was all over the news.
LOGIC to 4: Valid dilemma: P or Q; if P then R; if R then S; :. R or S
SOUNDNESS to 4: Almost certainly sound
TRUTH TO C
4. Almost certainly true by the preceding.
5. Certainly true – emergency management requires both.
LOGIC TO  C: Valid by singular modus ponens: if P then Q; P; :. Q
SOUNDNESS: Almost certainly sound.

2.  All wars kill innocent people and killing innocents is never right.  America’s invasion of Iraq was wrong because all wars are wrong.

CLARIFICATION
1. All war kills innocents.
2. All killing innocents is wrong.
:.
3. All war is wrong.
4. The
U.S. invasion of Iraq was war.
:. C. The U.S. Invasion of Iraq was wrong.

TRUTH TO 3
1. Almost certainly true.
2. Can’t tell.  Perhaps if the cause is righteous and important enough – as in World War 2 -- a certain amount of “collateral damage” is acceptable.
LOGIC: Valid categorical syllogism: All F are G; All G are H; :. All F are H
SOUNDNESS: Can’t tell.
TRUTH TO C
3. Can’t tell: the argument preceding argument for pacifism tempts me.
4. Certainly true: military invasion of another country is war.
LOGIC: valid categorical syllogism
SOUNDNESS: Can’t tell because I can’t tell about pacifist principle 3.

3.  If I get a job this summer, then, come fall, I'll either get a better car or move into a nicer apartment.  If I move into a nicer apartment then the money I earn will be gone by next spring.  If I get a better car the money I earn will be gone already this fall.  So, if I get a job this summer, the money I earn will be gone before next summer.  (Evaluate this on the assumption that it applies to you.  (HINT: if-then bridges may be needed to specify this complex argument.)  EXERCISES  12g:1 (adapted)

CLARIFICATION
1.  If I get a job this summer then I’ll either get a better car or move into a nicer apartment.
2. If I get a better car then the money I earn will be gone already in the fall.
3. If I get a better apartment then the money will be gone by next spring.
:.
4.  If I get a summer job the money will be gone this fall or by next spring.
5.  If the money is gone by this fall or next spring it will be gone before next summer.
:.
C. If I get a job this summer the money I earn will be gone before next summer.

TRUTH TO 4
1. Certainly false; I’m not in the market for either a car or an apartment. 
2.  Probably true for any job I could get by summer and any car that would be an upgrade on my 2004 Ion.
3.  Probably true for any job I could get by summer and any apartment that would be an upgrade to my current digs.
LOGIC: Valid if-then dilemma: If P then Q or R; If Q then S; if R then T; if P then Q or R
SOUNDNESS: Certainly unsound due to the certain falsity of 1.
TRUTH TO C
4. Can’t tell … if I did get this job, how much would it pay?
5.  Certainly true by the meanings of the terms.
LOGIC: Valid by Transitivity of Implication
SOUNDNESS: Can’t tell since I can’t tell on 4.