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

Multiple choice

According to the Mimamsa School, what are the three types of inference?

  1. Deductive, inductive, and abductive

  2. Categorical, hypothetical, and disjunctive

  3. Affirmative, negative, and universal

  4. Major, minor, and conclusion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Mimamsa School divides inference into three types: categorical, hypothetical, and disjunctive.

Multiple choice

Which of the following is not a characteristic of valid inference, according to the Mimamsa School?

  1. It must have a sound logical form

  2. It must be based on true premises

  3. It must lead to a true conclusion

  4. It must be accepted by all rational people
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Mimamsa School does not consider the acceptance of inference by all rational people to be a necessary condition for its validity.

Multiple choice

Which of the following is a modal operator?

  1. ¬

  2. ∧

  3. □

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

□ is a modal operator that represents necessity.

Multiple choice

Which of the following is a valid inference rule in modal logic?

  1. Modus ponens

  2. Modus tollens

  3. Necessitation

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

Necessitation is a valid inference rule in modal logic that allows us to infer □φ from φ.

Multiple choice

What is the converse of the necessitation rule?

  1. Universal instantiation

  2. Existential generalization

  3. Disjunctive syllogism

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

The converse of the necessitation rule is universal instantiation, which allows us to infer φ from □φ.

Multiple choice

Which of the following is a modal fallacy?

  1. Affirming the consequent

  2. Denying the antecedent

  3. Appeal to ignorance

  4. Fallacy of four terms
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Appeal to ignorance is a modal fallacy that occurs when we conclude that a proposition is true simply because we do not know that it is false.

Multiple choice

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

  1. It is raining.

  2. All dogs are mammals.

  3. It is possible that the moon is made of cheese.

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

A modal proposition is a proposition that contains a modal operator, such as □ or ◇.

Multiple choice

Which of the following is an example of a necessary proposition?

  1. It is raining.

  2. All dogs are mammals.

  3. It is possible that the moon is made of cheese.

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

2 + 2 = 4 is a necessary proposition because it is true in all possible worlds.

Multiple choice

Which of the following is an example of a contingent proposition?

  1. It is raining.

  2. All dogs are mammals.

  3. It is possible that the moon is made of cheese.

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

It is raining is a contingent proposition because it is not true in all possible worlds.

Multiple choice

Which of the following is an example of a deontic proposition?

  1. It is raining.

  2. All dogs are mammals.

  3. It is possible that the moon is made of cheese.

  4. You ought to keep your promises.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

You ought to keep your promises is a deontic proposition because it expresses an obligation.

Multiple choice

What was the name of the movement in the early 20th century that emphasized the importance of intuition and creativity in mathematics?

  1. The Intuitionist Movement

  2. The Constructivist Movement

  3. The Logicist Movement

  4. The Formalist Movement
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Intuitionist Movement was a movement in the early 20th century that emphasized the importance of intuition and creativity in mathematics. This movement was led by mathematicians such as L.E.J. Brouwer and Hermann Weyl.

Multiple choice

Which of the following statements is an example of inductive reasoning?

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

  2. The sun has risen every day for the past million years. Therefore, the sun will rise tomorrow.

  3. All metals are good conductors of electricity. Therefore, copper is a good conductor of electricity.

  4. All triangles have three sides. Therefore, this shape with three sides is a triangle.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is an example of inductive reasoning because it makes a generalization based on past observations. The premise states that the sun has risen every day for the past million years, and the conclusion states that the sun will rise tomorrow. While this conclusion is not necessarily true, it is based on the inductive reasoning that the past pattern will continue in the future.

Multiple choice

Which of the following statements is an example of deductive reasoning?

  1. All dogs are mammals. This animal is a dog. Therefore, this animal is a mammal.

  2. All birds can fly. This creature has wings. Therefore, this creature can fly.

  3. All roses are red. This flower is red. Therefore, this flower is a rose.

  4. All triangles have three sides. This shape has three sides. Therefore, this shape is a triangle.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is an example of deductive reasoning because the conclusion logically follows from the premises. The first premise states that all dogs are mammals, and the second premise states that this animal is a dog. Therefore, it can be logically concluded that this animal is a mammal.

Multiple choice

Which of the following statements is a logical fallacy?

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

  2. The sun has risen every day for the past million years. Therefore, the sun will rise tomorrow.

  3. All metals are good conductors of electricity. Therefore, copper is a good conductor of electricity.

  4. All triangles have three sides. Therefore, this shape with three sides is a triangle.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is a logical fallacy known as a hasty generalization. The premise states that all swans are white, but this does not necessarily mean that all birds are white. There are many other species of birds that are not white, such as penguins, crows, and blue jays.

Multiple choice

Which of the following statements is a logical fallacy?

  1. All dogs are mammals. This animal is a dog. Therefore, this animal is a mammal.

  2. All birds can fly. This creature has wings. Therefore, this creature can fly.

  3. All metals are good conductors of electricity. Therefore, copper is a good conductor of electricity.

  4. All triangles have three sides. Therefore, this shape with three sides is a triangle.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is a logical fallacy known as affirming the consequent. The premise states that all triangles have three sides, and the conclusion states that this shape with three sides is a triangle. However, the fact that this shape has three sides does not necessarily mean that it is a triangle. There are many other shapes that also have three sides, such as squares, rectangles, and hexagons.