Exercise 5.3
1. (a) No; Yes (d) No; No
(b) Yes; No (e) Yes; No
(c) Yes; No
ARGUMENT: Critical Thinking, Logic and the Fallacies
Chapter 5: Formal and Informal Logic
522
Exercise 7.1
1. Reflexive Symmetric Transitive (a) (b) (c) (d) (e) Note: (b) is not symmetric since Bill may be a brother of Sally without Sally being a brother of Bill (c) is not transitive since Bill may be a sibling of Sally and Sally may be a sibling
Exercise 13.3
1. Factors to consider include whether either or both twins are in a state of vital dependency upon each other; e.g., do the vital organs in question belong more to one twin than the other? whether there is anyone else who can provide this s
Exercise 1.3
1. Recall (p. 14) that an argument is an ad baculum if a conclusion is drawn or invited to be drawn on the basis of an appeal to force: (a) Yes (f) No (b) No (g) Yes (c) Yes (h) Yes (d) Yes (i) Yes (e) No (j) Yes
2. Recall (p. 14) that an ad
Exercise 1.2
1. (a) To think, a computer would need to be able to understand the meanings of words No computer, whatever its speed or sophistication, will ever be able to understand the meanings of words Therefore, no computer will ever think (b) The secr
Exercise 3.3
1. (a) I am a pacifist I am not a pacifist (c) I am a pacifist I am a loyalist (b) I am a pacifist I am not a pacifist (d) I am a pacifist I am a non-pacifist warmonger
(e) I am a pacifist I am not a pacifist and I am a warmonger I am not a p
Exercise 4.3
1. (a) True (f) False 2. p T T F F q T F T F
(b) True (g) True pq T F F F p F F T T
(c) False (h) True q F T F T p q F F F T
(d) True (i) True
(e) False (j) False pq T F F T
(p q) (p q) T F F T
Propositional forms (p q) (p q) and p q are equi
Exercise 4.4
1. (a) H = Bill is honest (b) E = Sue is encouraged by the result P = Sue is pleased with the process (c) B = Bill went to the movies S = Sue went to the movies (d) L = Bill was late E = Bill gave an excellent speech (e) L = Bill was late P =
Exercise 7.3
1. (a) 1. 2. 3. 4. 1. 2. 3. 4. 5. 6. (A B) (B A) (B A) (A B) [(A B) (B A)] [(B A) (A B)] (A B) (B A) A (A A) (A A) A AA AA (A A) (A A) AA A1 Sub A1 Sub 1, 2 Conj D3 Sub A3 Sub A2 Sub 1, 2 HS 3R 3, 4 Conj D3 Sub
(b)
ARGUMENT: Critical Thinking
Exercise 14.1
1. (a) Yes, since truth tables are effective, finite and mechanical (b) No, since although a coin flip is both finite and mechanical, it is not effective (c) No, since although consulting an encyclopedia is finite, it is likely not effective
Exercise 5.1
1. Recall (p. 102) that an argument is a uniform substitution instance of a given argument form if the argument can be obtained from the argument form by uniformly substituting propositions for propositional variables: (a) No 2. (a) No 3. (a)
Exercise 5.2
1. Recall (pp. 106f) that an equivocation occurs whenever an argument depends inappropriately on a semantic ambiguity and that an amphiboly occurs whenever an argument depends inappropriately on a grammatical ambiguity: (a) Equivocation; "pub
Exercise 14.3
1. (a) 1. K K p 2. K K + p 3. K K + p p (b) 1. K K p 2. If K K then (K ) + K + p p p p 3. (K ) + K + p p p (c) 1. If p K * then (K * ) + = K p p p 2. p K * p 3. (K * ) + = K p p
ARGUMENT: Critical Thinking, Logic and the Fallacies
(K2) (K+3)
Exercise 4.5
(a) P (R Q)
(b) P (~R ~Q)
(c) (P ~R) (~R Q)
(d) (P R) Q
(e) (P Q) R
(f) P (R Q)
(g) P R
1.
(h) P (R Q)
(i) P (R Q)
(j) Q (R (Q P)
2.
(a) D = Superman will die
K = Superman will be exposed to kryptonite
B = Superman will die because he is
expo
Exercise 4.2
1. (a) False (f) True 2. p T T F F q T F T F (b) False (g) False (p q) T F F F p F F T T (c) False (h) True q F T F T (d) True (i) False (e) False (j) False
(p q) F T T T
p v q F T T T
Propositional forms (p q) and p v q are equivalent truth
Exercise 3.1
1. Note: when evaluating a dialogue, consider each of the following: Are the participants equally matched? What is the goal? Is this a refutation? An instruction argument? An examination argument? Does the questioner ask clear and straightfor
Exercise 2.3
1. (a) Ad misericordiam (c) Ad hominem (circumstantial) (e) Ad populum (popularity) (g) Ad misericordiam (i) Ad hominem (circumstantial) 2. (a) Yes (f) Yes 3. -(b) Yes (g) No (c) Yes (h) No (b) Ad hominem (circumstantial) (d) Ad misericordiam
Exercise 2.1
1. (a) In a debate, the most helpful features for deciding an issue include being
rule-governed
presided over by a neutral speaker or chairperson
(b) In a debate, the most helpful features for advancing truth include having
multiple views bei
Exercise 1.4
1. Recall (p. 16) that an argument is an ad hominem if a conclusion is drawn or invited to be drawn on the basis of an appeal to some (alleged) fact about one's opponent: (a) Yes (f) Yes (b) Yes (g) Yes (c) No (h) Yes (d) Yes (i) No (e) Yes (