Reasoning
Logic and Fallacies
1,803 Questions
Understand the fundamentals of propositional logic, logical inference rules, and paradoxes. This set includes identifying logical fallacies, including those found in classical Nyaya logic. Strong grasp of these concepts is crucial for scoring well in the reasoning sections of competitive tests.
Propositional logic modelsLogical inference rulesTypes of logical fallaciesParadoxes and contingent truthsNyaya logic concepts
Logic and Fallacies Questions
Which of the following is a tautology?
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If it is raining, then the ground is wet.
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If it is raining, then the ground is dry.
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If it is raining, then the sun is shining.
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If it is raining, then the sun is not shining.
A
Correct answer
Explanation
A tautology is a propositional formula that is always true, regardless of the truth values of its component propositions. In this case, the proposition "If it is raining, then the ground is wet" is always true, because it is impossible for it to rain and the ground not to be wet.
Which of the following is a contingent proposition?
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If it is raining, then the ground is wet.
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If it is raining, then the ground is dry.
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If it is raining, then the sun is shining.
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If it is raining, then the sun is not shining.
C
Correct answer
Explanation
A contingent proposition is a propositional formula that is neither a tautology nor a contradiction. Its truth value depends on the truth values of its component propositions. In this case, the proposition "If it is raining, then the sun is shining" is contingent, because it is possible for it to be true (if it is raining and the sun is shining) or false (if it is raining and the sun is not shining).
Which of the following is a necessary proposition?
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If it is raining, then the ground is wet.
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If it is raining, then the ground is dry.
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If it is raining, then the sun is shining.
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If it is raining, then the sun is not shining.
A
Correct answer
Explanation
A necessary proposition is a propositional formula that is always true, regardless of the circumstances. In this case, the proposition "If it is raining, then the ground is wet" is necessary, because it is impossible for it to rain and the ground not to be wet.
Which of the following is a sufficient condition for it to be raining?
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The ground is wet.
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The sun is shining.
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The clouds are dark.
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The wind is blowing.
A
Correct answer
Explanation
A sufficient condition is a condition that, if it is true, guarantees the truth of another condition. In this case, if the ground is wet, then it is necessarily the case that it is raining.
Which of the following is a syllogism?
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Either it is raining or it is not raining.
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Either it is raining and the ground is wet, or it is not raining and the ground is dry.
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Either it is raining or the sun is shining.
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All men are mortal. Socrates is a man. Therefore, Socrates is mortal.
D
Correct answer
Explanation
A syllogism is a type of argument that consists of three parts: a major premise, a minor premise, and a conclusion. The major premise makes a general statement about a category of things. The minor premise identifies something as a member of that category. The conclusion then draws a conclusion about that thing based on the two premises. In this case, the major premise is "all men are mortal", the minor premise is "Socrates is a man", and the conclusion is "Socrates is mortal".
The slippery slope argument is a type of logical fallacy that warns against:
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Taking small steps towards a larger, undesirable outcome
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Ignoring the consequences of one's actions
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Relying on emotions rather than reason
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Failing to consider alternative perspectives
A
Correct answer
Explanation
The slippery slope argument is a logical fallacy that warns against taking small steps towards a larger, undesirable outcome. It suggests that once a certain action or decision is taken, it will inevitably lead to a series of subsequent actions or decisions that result in an undesirable outcome.
Which of the following is a common type of epistemic modal operator?
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K (knows)
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B (believes)
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M (might)
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P (possibly)
A
Correct answer
Explanation
The epistemic modal operator K is used to represent the knowledge of an agent.
Which of the following is a valid inference rule in epistemic logic?
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From Kφ and φ, infer Kφ
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From Bφ and φ, infer Kφ
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From Kφ and ¬φ, infer ¬Kφ
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From Bφ and ¬φ, infer ¬Bφ
A
Correct answer
Explanation
The inference rule Kφ ∧ φ ⊢ Kφ is a valid rule in epistemic logic, known as the rule of knowledge closure.
Which of the following is an example of an epistemic verb?
A
Correct answer
Explanation
Epistemic verbs are verbs that express knowledge or belief, such as 'know', 'believe', 'think', and 'guess'.
Which of the following is an example of an epistemic adverb?
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Certainly
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Probably
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Possibly
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Maybe
A
Correct answer
Explanation
Epistemic adverbs are adverbs that express knowledge or belief, such as 'certainly', 'probably', 'possibly', and 'maybe'.
Which of the following is an example of an epistemic noun?
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Knowledge
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Belief
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Opinion
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Hypothesis
A
Correct answer
Explanation
Epistemic nouns are nouns that express knowledge or belief, such as 'knowledge', 'belief', 'opinion', and 'hypothesis'.
Which of the following is an example of an epistemic preposition?
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About
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Of
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Concerning
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Regarding
A
Correct answer
Explanation
Epistemic prepositions are prepositions that express knowledge or belief, such as 'about', 'of', 'concerning', and 'regarding'.
Which of the following is an example of an epistemic interjection?
B
Correct answer
Explanation
Epistemic interjections are interjections that express knowledge or belief, such as 'wow!', 'really?', 'I see.', and 'aha!'.
Which logical connective is commonly used to represent the relationship between a stimulus and a response in psychology?
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Conjunction (∧)
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Disjunction (∨)
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Implication (→)
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Negation (¬)
C
Correct answer
Explanation
The implication connective (→) is often used to represent the relationship between a stimulus and a response, where the stimulus is the antecedent and the response is the consequent.
What is the term for a logical fallacy that occurs when a conclusion is drawn based on a limited number of observations or instances?
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Ad hoc fallacy
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Hasty generalization
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Appeal to ignorance
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Confirmation bias
B
Correct answer
Explanation
Hasty generalization is a logical fallacy that occurs when a conclusion is drawn based on a limited number of observations or instances, without considering alternative explanations or the possibility of exceptions.