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 a famous modal fallacy?

  1. The fallacy of affirming the consequent

  2. The fallacy of denying the antecedent

  3. The fallacy of modal transposition

  4. The fallacy of modal syllogism
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The fallacy of modal transposition is a modal fallacy that occurs when a modal operator is moved from one proposition to another in an invalid way. For example, the argument 'It is possible that Socrates is a philosopher, therefore it is necessary that Socrates is a philosopher' is a fallacy of modal transposition.

Multiple choice

What is the Münchhausen trilemma?

  1. A logical argument that shows that all attempts to justify our beliefs must ultimately rely on circular reasoning, infinite regress, or an unjustified assumption.

  2. A logical argument that shows that all attempts to justify our beliefs must ultimately rely on evidence, reason, or testimony.

  3. A logical argument that shows that all attempts to justify our beliefs must ultimately rely on intuition, faith, or revelation.

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

The Münchhausen trilemma is a logical argument that shows that all attempts to justify our beliefs must ultimately rely on circular reasoning, infinite regress, or an unjustified assumption.

Multiple choice

Which of the following is a key concept in Charles Sanders Peirce's pragmatism?

  1. Abduction

  2. Deduction

  3. Induction

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

Abduction is a key concept in Charles Sanders Peirce's pragmatism. It is the process of forming a hypothesis based on limited evidence.

Multiple choice

Which of the following statements is an example of a deontic statement?

  1. The sky is blue.

  2. You should tell the truth.

  3. The Earth revolves around the Sun.

  4. The population of China is over 1 billion.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A deontic statement expresses a moral obligation, permission, or prohibition. In this case, "You should tell the truth" conveys a moral obligation to be honest.

Multiple choice

Which logical operator is commonly used to represent obligation in deontic logic?

  1. ¬ (not)

  2. ∧ (and)

  3. ∨ (or)

  4. → (implication)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In deontic logic, the implication operator (→) is often used to represent obligation. For example, the statement "It is obligatory to tell the truth" can be expressed as "Truth-telling → Obligation".

Multiple choice

Which logical operator is commonly used to represent permission in deontic logic?

  1. ¬ (not)

  2. ∧ (and)

  3. ∨ (or)

  4. → (implication)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In deontic logic, the disjunction operator (∨) is often used to represent permission. For example, the statement "It is permissible to tell the truth" can be expressed as "Truth-telling ∨ Permission".

Multiple choice

Which logical connective is used to express the idea of "and" in predicate logic?

  1. ∧

  2. ∨

  3. →

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

The logical connective ∧ is used to express the idea of "and" in predicate logic. It is also known as the conjunction connective.

Multiple choice

Which of the following is an example of a perceptual judgment?

  1. The sky is blue.

  2. 2 + 2 = 4.

  3. God exists.

  4. I am happy.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A perceptual judgment is a statement about something that is directly perceived through the senses. The sky is blue is a statement about a visual perception.

Multiple choice

Which of the following is an example of a non-perceptual belief?

  1. The Earth is round.

  2. God exists.

  3. 2 + 2 = 4.

  4. I am happy.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

God exists is an example of a non-perceptual belief. This is because the existence of God cannot be directly perceived.

Multiple choice

Which of the following is an example of a non-perceptual justification?

  1. I saw a red apple.

  2. I heard a bird singing.

  3. I smelled a flower.

  4. 2 + 2 = 4.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

2 + 2 = 4 is an example of a non-perceptual justification. This is because the truth of this statement is not based on perception.

Multiple choice

Which principle states that the meaning of a complex expression is determined by the meanings of its constituent parts and the way they are combined?

  1. Compositionality Principle

  2. Truth-Conditional Principle

  3. Referential Principle

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

The Compositionality Principle is a fundamental principle in Formal Semantics, stating that the meaning of a complex expression is derived from the meanings of its parts and the rules of combination.

Multiple choice

Which type of semantic theory assigns a truth value to every sentence in a language?

  1. Truth-Conditional Semantics

  2. Referential Semantics

  3. Compositional Semantics

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

Truth-conditional semantics assigns a truth value (true or false) to every sentence in a language, providing a formal framework for evaluating the truth or falsity of statements.

Multiple choice

Which of the following is an example of a logical fallacy commonly found in argumentative essays?

  1. Ad Hominem

  2. Straw Man

  3. Circular Reasoning

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

Ad Hominem, Straw Man, and Circular Reasoning are all examples of logical fallacies that can weaken the argument presented in an essay.

Multiple choice

Which of the following is an example of a logical fallacy based on a false dichotomy?

  1. Either you support the new policy or you are against progress

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

  3. This medicine is either effective or it is not

  4. All dogs are mammals, therefore all mammals are dogs
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The statement 'Either you support the new policy or you are against progress' presents a false dichotomy by implying that there are only two options, when in reality there may be more nuanced positions or alternatives.

Multiple choice

Which of the following is an example of a logical fallacy based on a hasty generalization?

  1. All swans are white, therefore all birds are white

  2. I met a rude person from Country X, therefore all people from Country X are rude

  3. This medicine worked for me, therefore it will work for everyone

  4. The stock market has been rising for the past few months, therefore it will continue to rise indefinitely
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The statement 'I met a rude person from Country X, therefore all people from Country X are rude' is a hasty generalization because it draws a broad conclusion based on a limited sample size.