Phil 106: Critical Thinking

LARKIN: Fall 2002

 

TEST #2: Review

Truth-Functional Logic

 

I.                     Multiple Choice: (Directions: Choose the best available answer for each of the questions below.  Clearly record your choices on the separate answer sheet provided.)

A.      Truth and Validity

1.        Example:

If an argument is invalid, then we definitely know which of the following:

a.        It has all true premises and a true conclusion

b.        It has all true premises and a false conclusion

c.        It has some false premise

d.        None of the above

 

2.        Read: Chapter One 1.7 and 1.9

 

B.       Translations

1.        Example:

Which of the following is the best symbolic translation of the English sentence “Both Barry will hit a home run if the Cardinals do not win and Barry will hit a home run unless the Cardinals win” (B = Barry will hit a home run, C = Cardinals will win):

a.        (B É C) · (B É C)

b.        (B É ~C) · (B É C)

c.        (C É B) · (B v C)

d.        (~C É B) · (B v C)

 

2.        Read:  Chapter Eight: 8.1-8.3

3.        Practice:  p. 311 IV, p. 320 III

 

C.      Truth-Value Computations

1.        Example:

If  A and B are true but P and Q are unknown, which of the following claims are definitely true:

a.        (A · ~B) · (P v Q)

b.         (A · ~B) v (P v A)

c.        (A · ~B) É (P v Q)

d.        both a and b

e.        both b and c

 

2.        Read: Chapter Eight: 8.1-8.3

3.        Practice: p. 310 II and III, p. 319 I, II

 

D.      Argument Form Identification

1.        Example:

“If the Cardinals do not win, then Barry will go deep at least once.  Since the Cardinal will win, Barry will not go deep at least once.”  This argument is best described as which of the following:

a.        Affirming the Antecedent

b.        Affirming the Consequent

c.        Denying the Antecedent

d.        Denying the Consequent   

 

2.        Read:  Chapter Eight: 8.5 C and D

 

II.                   Truth Table Analysis (Directions:  Determine whether the following arguments are valid or not by constructing a truth table)

A.      Example:

(P v Q) É (Q · R)

~(R v Q)

/\  ~P

B.      Read:  Chapter Eight: 8.5 B

C.      Practice:  p. 333 III