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 logical connective?

  1. And

  2. Or

  3. Not

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

Logical connectives are words or symbols that connect propositions and determine the overall truth value of a compound proposition.

Multiple choice

Which of the following is an example of a syllogism?

  1. All men are mortal. Socrates is a man. Therefore, Socrates is mortal.

  2. It is raining outside. I have an umbrella. Therefore, I will not get wet.

  3. I am hungry. I have food. Therefore, I will eat.

  4. The sky is blue. The grass is green. Therefore, the world is beautiful.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A syllogism is a logical argument that consists of two premises and a conclusion, where the conclusion is inferred from the premises.

Multiple choice

What is the rule of inference known as modus ponens?

  1. If P, then Q. P. Therefore, Q.

  2. If P, then Q. Not Q. Therefore, not P.

  3. P or Q. P. Therefore, not Q.

  4. P and Q. Therefore, P or Q.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Modus ponens is a rule of inference that allows us to infer the consequent (Q) from the antecedent (P) and the conditional statement (If P, then Q).

Multiple choice

Which of the following is an example of a tautology?

  1. (P or Q) and (not P and not Q)

  2. If P, then P

  3. P and not P

  4. P or not P
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A tautology is a compound proposition that is true in all possible cases.

Multiple choice

Which of the following is a logically valid argument form?

  1. P or Q. Not P. Therefore, Q.

  2. If P, then Q. Q. Therefore, P.

  3. P and Q. Therefore, not P or not Q.

  4. If P, then Q. Not Q. Therefore, P.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This argument form is known as disjunctive syllogism and is logically valid because if one of the disjuncts (P or Q) is true and the other (P) is false, then the remaining disjunct (Q) must be true.

Multiple choice

What is the truth value of the following proposition: (P and Q) or (not P and not Q)?

  1. True

  2. False

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

Using a truth table, we can determine that the proposition is true in all possible cases.

Multiple choice

Which of the following is a logical connective?

  1. If

  2. Then

  3. Therefore

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

Logical connectives are words or symbols that connect propositions and determine the overall truth value of a compound proposition.

Multiple choice

Which of the following is an example of a syllogism?

  1. All fruits contain seeds. Apples are fruits. Therefore, apples contain seeds.

  2. I am hungry. I have food. Therefore, I will eat.

  3. The sky is blue. The grass is green. Therefore, the world is beautiful.

  4. It is raining outside. I have an umbrella. Therefore, I will not get wet.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A syllogism is a logical argument that consists of two premises and a conclusion, where the conclusion is inferred from the premises.

Multiple choice

What is the rule of inference known as modus tollens?

  1. If P, then Q. Not Q. Therefore, not P.

  2. If P, then Q. P. Therefore, Q.

  3. P or Q. P. Therefore, not Q.

  4. P and Q. Therefore, P or Q.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Modus tollens is a rule of inference that allows us to infer the negation of the antecedent (not P) from the conditional statement (If P, then Q) and the negation of the consequent (not Q).

Multiple choice

Which of the following is an example of a contradiction?

  1. (P and Q) and (not P and not Q)

  2. If P, then P

  3. P and not P

  4. P or not P
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A contradiction is a compound proposition that is false in all possible cases.

Multiple choice

What is Aristotle's theory of the syllogism?

  1. A deductive argument consisting of two premises and a conclusion

  2. A deductive argument consisting of one premise and a conclusion

  3. An inductive argument consisting of two premises and a conclusion

  4. An inductive argument consisting of one premise and a conclusion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aristotle's theory of the syllogism states that a syllogism is a deductive argument consisting of two premises and a conclusion.

Multiple choice

What is Aristotle's theory of logic?

  1. Logic is the study of reasoning

  2. Logic is the study of arguments

  3. Logic is the study of syllogisms

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

Aristotle's theory of logic states that logic is the study of reasoning, arguments, and syllogisms.

Multiple choice

Which of the following is an example of semantic extension?

  1. The word 'computer' originally meant 'a person who computes'

  2. The word 'table' originally meant 'a flat surface'

  3. The word 'book' originally meant 'a written work'

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

All of the above examples are examples of semantic extension.

Multiple choice

Which of the following is NOT a theory of meaning?

  1. The referential theory of meaning

  2. The descriptivist theory of meaning

  3. The verificationist theory of meaning

  4. The emotivist theory of meaning
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The verificationist theory of meaning is a theory of truth, not a theory of meaning.

Multiple choice

What is the compositional rule of inference?

  1. A rule of inference that allows us to combine two fuzzy sets to obtain a new fuzzy set.

  2. A rule of inference that allows us to combine a fuzzy set and a crisp set to obtain a new fuzzy set.

  3. A rule of inference that allows us to combine two crisp sets to obtain a new fuzzy set.

  4. A rule of inference that allows us to combine a fuzzy set and a logical expression to obtain a new fuzzy set.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The compositional rule of inference is a rule of inference that allows us to combine two fuzzy sets to obtain a new fuzzy set. It is a fundamental rule of fuzzy logic.