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 final causality?

  1. The purpose of a house is to provide shelter

  2. The purpose of a cake is to be eaten

  3. The purpose of a painting is to be admired

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

All of the above are examples of final causality because they involve a purpose (to provide shelter, to be eaten, to be admired) that brings about an effect.

Multiple choice

Which of the following is not a necessary condition for causality?

  1. A cause must be efficient

  2. A cause must be formal

  3. A cause must be material

  4. A cause must be final
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

None of the above are necessary conditions for causality. A cause does not need to be efficient, formal, material, or final in order to be a cause.

Multiple choice

Which of the following is a sufficient condition for causality?

  1. A cause must precede its effect

  2. A cause must be sufficient to bring about its effect

  3. A cause must be related to its effect

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

A cause must be sufficient to bring about its effect in order to be a cause. The other conditions are necessary but not sufficient.

Multiple choice

Which of the following is not a sufficient condition for causality?

  1. A cause must precede its effect

  2. A cause must be related to its effect

  3. A cause must be efficient

  4. A cause must be final
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

None of the above are sufficient conditions for causality. A cause can precede its effect, be related to its effect, be efficient, or be final without being a cause.

Multiple choice

Which of the following is not a necessary and sufficient condition for causality?

  1. A cause must precede its effect

  2. A cause must be related to its effect

  3. A cause must be efficient

  4. A cause must be final
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

None of the above are necessary and sufficient conditions for causality. A cause can precede its effect, be related to its effect, be efficient, or be final without being a cause.

Multiple choice

Which of the following is not a type of legal argument?

  1. Deductive argument

  2. Inductive argument

  3. Analogical argument

  4. Emotional argument
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Emotional arguments are not a type of legal argument. Legal arguments are based on logic and reason, not on emotion.

Multiple choice

In propositional logic, a proposition is a statement that is either true or false, but not both.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A proposition is a declarative statement that can be evaluated as either true or false, but not both simultaneously.

Multiple choice

The symbol "¬" is used to denote which logical operator?

  1. Conjunction

  2. Disjunction

  3. Negation

  4. Implication
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The symbol "¬" is used to denote the negation operator, which changes the truth value of a proposition to its opposite.

Multiple choice

The truth table for the logical operator "∧" (conjunction) is as follows:

  1. P Q P ∧ Q True True True True False False False True False False False False

  2. P Q P ∧ Q True True False True False True False True True False False True

  3. P Q P ∧ Q True True True True False True False True False False False True

  4. P Q P ∧ Q True True False True False False False True True False False False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The truth table for conjunction shows that the result is true only when both operands are true.

Multiple choice

The logical operator "∨" (disjunction) is also known as the:

  1. Inclusive OR

  2. Exclusive OR

  3. Negation

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

The disjunction operator "∨" is also known as the inclusive OR, which means that the result is true if either or both operands are true.

Multiple choice

The truth table for the logical operator "→" (implication) is as follows:

  1. P Q P → Q True True True True False False False True True False False True

  2. P Q P → Q True True False True False True False True False False False True

  3. P Q P → Q True True True True False True False True True False False False

  4. P Q P → Q True True False True False False False True True False False False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The truth table for implication shows that the result is false only when the antecedent is true and the consequent is false.

Multiple choice

The logical operator "↔" (biconditional) is equivalent to which of the following compound propositions?

  1. (P ∧ Q) ∨ (¬P ∧ ¬Q)

  2. (P → Q) ∧ (Q → P)

  3. (P ∨ Q) ∧ (¬P ∨ ¬Q)

  4. (P ∧ ¬Q) ∨ (¬P ∧ Q)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The biconditional operator "↔" is equivalent to the compound proposition (P → Q) ∧ (Q → P), which means that both the implication from P to Q and the implication from Q to P must be true.

Multiple choice

In propositional logic, a tautology is a compound proposition that is always true, regardless of the truth values of its component propositions.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A tautology is a compound proposition that is always true, regardless of the truth values of its component propositions.

Multiple choice

The following proposition is an example of a tautology:

  1. (P ∨ ¬P)

  2. (P ∧ Q) → P

  3. (P → Q) → ¬Q

  4. (P ∨ Q) ∧ (¬P ∨ ¬Q)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

(P ∨ ¬P) is a tautology because it is always true, regardless of the truth value of P.

Multiple choice

A contradiction is a compound proposition that is always false, regardless of the truth values of its component propositions.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A contradiction is a compound proposition that is always false, regardless of the truth values of its component propositions.