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

What is the fallacy of the excluded middle?

  1. Assuming the conclusion is true

  2. Reversing the order of the premises

  3. Assuming that a statement is either true or false, with no middle ground

  4. Drawing a conclusion from a false premise
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The fallacy of the excluded middle occurs when it is assumed that a statement must be either true or false, without considering the possibility of a middle ground or a third option.

Multiple choice

Which of these statements is a logical consequence of the statement 'If P, then Q'?

  1. If Q, then P

  2. If not P, then not Q

  3. If not Q, then not P

  4. If P, then not Q
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The statement 'If P, then Q' implies that whenever P is true, Q must also be true. Therefore, if P is false, then Q cannot be true, which is expressed by the statement 'If not P, then not Q'.

Multiple choice

What is the term for the logical fallacy of affirming the consequent?

  1. Ad ignorantiam

  2. Post hoc ergo propter hoc

  3. Affirming the consequent

  4. Denying the antecedent
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Affirming the consequent is a logical fallacy that occurs when someone assumes that because the consequent of a conditional statement is true, the antecedent must also be true.

Multiple choice

What is the term for the logical fallacy of denying the antecedent?

  1. Ad ignorantiam

  2. Post hoc ergo propter hoc

  3. Affirming the consequent

  4. Denying the antecedent
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Denying the antecedent is a logical fallacy that occurs when someone assumes that because the antecedent of a conditional statement is false, the consequent must also be false.

Multiple choice

What is the term for the logical fallacy of appealing to ignorance?

  1. Ad ignorantiam

  2. Post hoc ergo propter hoc

  3. Affirming the consequent

  4. Denying the antecedent
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ad ignorantiam is a logical fallacy that occurs when someone assumes that a statement is true simply because it has not been proven false, or that a statement is false simply because it has not been proven true.

Multiple choice

Which of the following is a valid logical argument?

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

  2. If it is raining, then the ground is wet. The ground is not wet. Therefore, it is not raining.

  3. If it is raining, then the ground is wet. It is not raining. Therefore, the ground is not wet.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is a valid argument because the conclusion follows logically from the premises. If it is raining, then the ground is wet. It is raining. Therefore, the ground is wet.

Multiple choice

Which of the following is a formal fallacy?

  1. Affirming the consequent

  2. Denying the antecedent

  3. Appeal to emotion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Affirming the consequent is a formal fallacy that occurs when someone assumes that because the consequent of a conditional statement is true, the antecedent must also be true. For example, "If it is raining, then the ground is wet. The ground is wet. Therefore, it is raining." This is a fallacy because the ground could be wet for other reasons, such as someone watering the lawn.

Multiple choice

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

  1. All dogs are mammals. Fido is a dog. Therefore, Fido is a mammal.

  2. Most people like chocolate. I am a person. Therefore, I like chocolate.

  3. The sky is blue. The grass is green. Therefore, the sky is not green.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A deductive argument is a type of argument in which the conclusion is guaranteed to be true if the premises are true. In the example above, the premises are "All dogs are mammals" and "Fido is a dog." The conclusion is "Therefore, Fido is a mammal." Since the premises are true, the conclusion must also be true.

Multiple choice

Which of the following is an example of an inductive argument?

  1. All dogs are mammals. Fido is a dog. Therefore, Fido is a mammal.

  2. Most people like chocolate. I am a person. Therefore, I like chocolate.

  3. The sky is blue. The grass is green. Therefore, the sky is not green.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An inductive argument is a type of argument in which the conclusion is not guaranteed to be true, even if the premises are true. In the example above, the premises are "Most people like chocolate" and "I am a person." The conclusion is "Therefore, I like chocolate." Since the premises are not certain, the conclusion is also not certain.

Multiple choice

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

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

  2. Either it is raining or it is not raining.

  3. It is raining and the ground is wet.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A hypothetical proposition is a type of proposition that makes a statement about the relationship between two or more propositions. In the example above, the proposition "If it is raining, then the ground is wet." is a hypothetical proposition because it makes a statement about the relationship between the proposition "It is raining" and the proposition "The ground is wet."

Multiple choice

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

  1. Either it is raining or it is not raining.

  2. It is raining and the ground is wet.

  3. All dogs are mammals.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A disjunctive proposition is a type of proposition that makes a statement about the relationship between two or more propositions. In the example above, the proposition "Either it is raining or it is not raining." is a disjunctive proposition because it makes a statement about the relationship between the proposition "It is raining" and the proposition "It is not raining."

Multiple choice

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

  1. It is raining and the ground is wet.

  2. Either it is raining or it is not raining.

  3. All dogs are mammals.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A conjunctive proposition is a type of proposition that makes a statement about the relationship between two or more propositions. In the example above, the proposition "It is raining and the ground is wet." is a conjunctive proposition because it makes a statement about the relationship between the proposition "It is raining" and the proposition "The ground is wet."

Multiple choice

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

  1. It is not raining.

  2. Either it is raining or it is not raining.

  3. All dogs are mammals.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A negation proposition is a type of proposition that makes a statement about the truth or falsity of another proposition. In the example above, the proposition "It is not raining." is a negation proposition because it makes a statement about the truth or falsity of the proposition "It is raining."

Multiple choice

Which of the following is an example of a tautology?

  1. If it is raining, then it is raining.

  2. Either it is raining or it is not raining.

  3. All dogs are mammals.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A tautology is a type of proposition that is always true, regardless of the truth or falsity of its component propositions. In the example above, the proposition "If it is raining, then it is raining." is a tautology because it is always true, regardless of whether it is actually raining or not.

Multiple choice

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

  1. It is possible that it is raining.

  2. Either it is raining or it is not raining.

  3. All dogs are mammals.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A modal proposition is a type of proposition that makes a statement about the possibility, necessity, or impossibility of another proposition. In the example above, the proposition "It is possible that it is raining." is a modal proposition because it makes a statement about the possibility of the proposition "It is raining."