CLAST Logical Reasoning 2 — Questions and Answers
Question 1: Which of the following is an example of the logical fallacy known as 'ad hominem'?
- Attacking the person making an argument rather than the argument itself (Correct answer)
- Drawing a conclusion that doesn't follow from the premises
- Assuming that because two events are correlated they are causally related
- Appealing to the majority opinion to support a claim
Correct answer: Attacking the person making an argument rather than the argument itself
Ad hominem is a fallacy that attacks the character or credibility of the person making an argument instead of addressing the argument's content.
Question 2: If the statement 'No reptiles are warm-blooded' is true, which of the following must also be true?
- All warm-blooded animals are reptiles
- No warm-blooded animals are reptiles (Correct answer)
- Some reptiles are warm-blooded
- All reptiles are cold-blooded mammals
Correct answer: No warm-blooded animals are reptiles
If no reptiles are warm-blooded, then by conversion of the universal negative, no warm-blooded animals are reptiles.
Question 3: A researcher concludes that ice cream causes drowning because both increase in summer. This is an example of:
- Valid deductive reasoning
- Confusing correlation with causation (Correct answer)
- An ad hominem fallacy
- A valid inductive generalization
Correct answer: Confusing correlation with causation
Both ice cream consumption and drowning increase in summer due to hot weather — a third factor — not because one causes the other.
Question 4: Which argument form is VALID?
- If P then Q; Q is true; therefore P is true
- If P then Q; P is false; therefore Q is false
- If P then Q; P is true; therefore Q is true (Correct answer)
- If P then Q; Q is false; therefore P is true
Correct answer: If P then Q; P is true; therefore Q is true
Modus ponens — 'If P then Q; P is true; therefore Q is true' — is the fundamental valid conditional argument form.
Question 5: The argument 'Everyone on the team agrees with the plan, so it must be correct' commits which fallacy?
- False dilemma
- Appeal to authority
- Ad populum (appeal to the majority) (Correct answer)
- Hasty generalization
Correct answer: Ad populum (appeal to the majority)
Appeal to the majority (ad populum) mistakes widespread agreement for truth, which is not a logically valid basis for a conclusion.
Question 6: Given: 'All doctors are college graduates' and 'Maria is a college graduate.' What can be logically concluded?
- Maria is a doctor
- Maria may or may not be a doctor (Correct answer)
- Maria is not a doctor
- Maria went to medical school
Correct answer: Maria may or may not be a doctor
Being a college graduate is a necessary but not sufficient condition for being a doctor, so Maria's status as a doctor cannot be determined.
Question 7: Which of the following best describes a 'sound' argument?
- An argument that is valid and has at least one true premise
- An argument that is valid and has all true premises (Correct answer)
- An argument whose conclusion is impossible to disprove
- An argument that most people find persuasive
Correct answer: An argument that is valid and has all true premises
A sound argument must be both logically valid (the conclusion follows from the premises) and have all premises that are actually true.
CLAST Logical Reasoning 2
Which of the following is an example of the logical fallacy known as 'ad hominem'?