Reasoning

Logic and Fallacies

1,716 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

Multiple choice

Which of the following is an example of a dilemma argument?

  1. Either you study hard or you fail the exam.

  2. If you study hard, you will pass the exam.

  3. If you don't study hard, you will fail the exam.

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A dilemma argument presents two or more unappealing alternatives, forcing a choice between them. In this case, the two alternatives are 'study hard' and 'fail the exam'.

Multiple choice

Which of the following is an example of a hypothetical syllogism?

  1. If it is raining, then the grass is wet. It is raining. Therefore, the grass is wet.

  2. Either you study hard or you fail the exam. You studied hard. Therefore, you will pass the exam.

  3. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A hypothetical syllogism is a type of argument that consists of a hypothetical premise and a categorical premise, followed by a conclusion. In this case, the hypothetical premise is 'Either you study hard or you fail the exam', the categorical premise is 'You studied hard', and the conclusion is 'Therefore, you will pass the exam'.

Multiple choice

Which of the following is a logically equivalent statement to 'It is not the case that both A and B are true'?

  1. Either A is false or B is false.

  2. Neither A nor B is true.

  3. A is false and B is false.

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

These statements are all logically equivalent because they convey the same meaning. They express the negation of the conjunction of 'A' and 'B'.

Multiple choice

Which of the following is an example of a modus tollens argument?

  1. If it is raining, then the grass is wet. It is raining. Therefore, the grass is wet.

  2. Either you study hard or you fail the exam. You didn't study hard. Therefore, you failed the exam.

  3. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Modus tollens is a type of argument that consists of a conditional premise, a negation of the consequent, and a conclusion. In this case, the conditional premise is 'Either you study hard or you fail the exam', the negation of the consequent is 'You didn't study hard', and the conclusion is 'Therefore, you failed the exam'.

Multiple choice

What is the fallacy committed in the following argument: All swans are white. I saw a black bird. Therefore, it cannot be a swan.

  1. Affirming the consequent

  2. Denying the antecedent

  3. Appeal to ignorance

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Denying the antecedent is a fallacy that occurs when someone mistakenly infers the falsity of the antecedent from the falsity of the consequent. In this case, the argument incorrectly concludes that 'it cannot be a swan' based on the true statements 'all swans are white' and 'I saw a black bird'.

Multiple choice

Which of the following is a logically equivalent statement to 'If A, then B'?

  1. B only if A

  2. A is sufficient for B

  3. B is necessary for A

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

These statements are all logically equivalent because they convey the same meaning. They express the conditional relationship between 'A' and 'B'.

Multiple choice

What is the term used to describe the process of deriving logical conclusions from a set of premises?

  1. Deduction

  2. Induction

  3. Falsification

  4. Verification
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Deduction is the process of deriving logical conclusions from a set of premises. It involves using logical rules to infer new statements that are necessarily true if the premises are true.

Multiple choice

What is the term used to describe the process of making logical conclusions from a set of premises?

  1. Deduction

  2. Induction

  3. Falsification

  4. Verification
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Deduction is the process of making logical conclusions from a set of premises. It involves using logical rules to infer new statements that are necessarily true if the premises are true.

Multiple choice

Which of the following is an example of an intuitive belief?

  1. The belief that the Earth is round

  2. The belief that the sun is the center of the solar system

  3. The belief that there is a God

  4. The belief that all humans are equal
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The belief that there is a God is an example of an intuitive belief because it is a belief that is not based on conscious reasoning or logical analysis. It is a belief that is simply held to be true.

Multiple choice

Which of the following is an example of a rational belief?

  1. The belief that the Earth is round

  2. The belief that the sun is the center of the solar system

  3. The belief that there is a God

  4. The belief that all humans are equal
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The belief that the Earth is round is an example of a rational belief because it is a belief that is based on conscious reasoning and logical analysis. It is a belief that is supported by evidence and logical arguments.

Multiple choice

What is the Paradox of the Liar?

  1. A statement that asserts its own falsity.

  2. A statement that asserts its own truth.

  3. A statement that is both true and false.

  4. A statement that is neither true nor false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Paradox of the Liar is a statement that asserts its own falsity. It is a paradox because it leads to a contradiction: if the statement is true, then it must be false, and if it is false, then it must be true.

Multiple choice

Which of the following is a deontic modal operator?

  1. □ (necessarily)

  2. ◇ (possibly)

  3. O (obligatory)

  4. P (permitted)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Deontic modal operators are used to express obligation, permission, and other normative concepts.

Multiple choice

Which of the following is an example of a modal fallacy?

  1. Affirming the consequent

  2. Denying the antecedent

  3. Appeal to ignorance

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Modal fallacies are informal fallacies that involve the misuse of modal operators.

Multiple choice

What is the difference between a strict conditional and a subjunctive conditional?

  1. A strict conditional is true if and only if the antecedent is true and the consequent is true, while a subjunctive conditional is true if and only if the antecedent is false and the consequent is true.

  2. A strict conditional is true if and only if the antecedent is true and the consequent is true, while a subjunctive conditional is true if and only if the antecedent is true and the consequent is false.

  3. A strict conditional is true if and only if the antecedent is false and the consequent is true, while a subjunctive conditional is true if and only if the antecedent is true and the consequent is true.

  4. A strict conditional is true if and only if the antecedent is false and the consequent is false, while a subjunctive conditional is true if and only if the antecedent is true and the consequent is false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Strict conditionals are used to express necessary relationships between propositions, while subjunctive conditionals are used to express possible relationships between propositions.

Multiple choice

Which of the following is an example of a strict conditional?

  1. If it is raining, then the ground is wet.

  2. If I study hard, then I will get a good grade.

  3. If I were taller, then I could reach the top shelf.

  4. If I had won the lottery, then I would be rich.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Strict conditionals are used to express necessary relationships between propositions.