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 sound logical argument?

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

  2. All dogs are mammals. Cats are not dogs. Therefore, cats are not mammals.

  3. Some birds can fly. Penguins are birds. Therefore, penguins can fly.

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

A sound logical argument is an argument that is both valid and has true premises.

Multiple choice

Which of the following is a fallacy?

  1. Affirming the consequent

  2. Denying the antecedent

  3. Appeal to ignorance

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

A fallacy is an argument that is invalid or has false premises.

Multiple choice

What is the fallacy of affirming the consequent?

  1. Assuming that the conclusion of an argument is true because the premises are true

  2. Assuming that the antecedent of an argument is false because the conclusion is false

  3. Assuming that a proposition is true because it has not been proven false

  4. Assuming that a proposition is false because it has not been proven true
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The fallacy of affirming the consequent is a type of logical fallacy in which it is assumed that the conclusion of an argument is true because the premises are true.

Multiple choice

What is the fallacy of denying the antecedent?

  1. Assuming that the conclusion of an argument is true because the premises are true

  2. Assuming that the antecedent of an argument is false because the conclusion is false

  3. Assuming that a proposition is true because it has not been proven false

  4. Assuming that a proposition is false because it has not been proven true
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The fallacy of denying the antecedent is a type of logical fallacy in which it is assumed that the antecedent of an argument is false because the conclusion is false.

Multiple choice

What is the fallacy of assuming that a proposition is false because it has not been proven true?

  1. Affirming the consequent

  2. Denying the antecedent

  3. Appeal to ignorance

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

The fallacy of assuming that a proposition is false because it has not been proven true is a type of logical fallacy in which it is assumed that a proposition is false because it has not been proven true.

Multiple choice

What is the 'rule-following paradox'?

  1. The paradox that arises when we try to follow a rule that is not clear or unambiguous.

  2. The paradox that arises when we try to follow a rule that is too clear and unambiguous.

  3. The paradox that arises when we try to follow a rule that is both clear and unambiguous.

  4. The paradox that arises when we try to follow a rule that is neither clear nor unambiguous.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wittgenstein argued that there is a paradox in the idea of following a rule. This is because, in order to follow a rule, we must first understand what the rule means. However, the meaning of a rule is not something that is fixed and unchanging, but rather something that is determined by the context in which it is used. This means that there is always the possibility that we will misunderstand the rule and follow it incorrectly.

Multiple choice

Which of the following is an example of a rational justification for a belief?

  1. I believe it because it feels right

  2. I believe it because it is popular

  3. I believe it because it is supported by evidence and logical reasoning

  4. I believe it because my favorite celebrity believes it
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A rational justification is based on evidence, logical reasoning, and sound arguments, rather than personal feelings, popularity, or external influences.

Multiple choice

Which of the following is an example of an unreliable belief?

  1. The sun is a star.

  2. The Earth is flat.

  3. 2 + 2 = 5.

  4. There is a teapot orbiting the sun.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The belief that the Earth is flat is unreliable because it is inconsistent with other beliefs, incoherent with our understanding of the universe, and does not correspond to the truth.

Multiple choice

Which of the following is a response to the problem of induction?

  1. The principle of uniformity of nature

  2. The principle of causality

  3. The principle of sufficient reason

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

The principle of uniformity of nature, the principle of causality, and the principle of sufficient reason are all responses to the problem of induction.

Multiple choice

Which of the following is an example of a logical fallacy that can weaken the supporting evidence in an expository essay?

  1. Ad hominem

  2. Straw man

  3. Post hoc ergo propter hoc

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

Logical fallacies such as ad hominem, straw man, and post hoc ergo propter hoc can weaken the supporting evidence in an expository essay.

Multiple choice

What is a hypothesis?

  1. A proposed explanation for a phenomenon

  2. A statement of fact

  3. A prediction about the outcome of an experiment

  4. A conclusion drawn from an experiment
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A hypothesis is a tentative explanation that can be tested through experimentation.

Multiple choice

Which of the following is a necessary condition for something to be possible?

  1. It is not self-contradictory.

  2. It is logically consistent.

  3. It is physically possible.

  4. It is morally permissible.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A necessary condition for something to be possible is that it is not self-contradictory. If something is self-contradictory, then it is impossible by definition.

Multiple choice

Which of the following is a sufficient condition for something to be necessary?

  1. It is logically true.

  2. It is metaphysically necessary.

  3. It is morally necessary.

  4. It is epistemically necessary.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A sufficient condition for something to be necessary is that it is logically true. If something is logically true, then it is necessary by definition.

Multiple choice

Which of the following is an example of an epistemic necessity?

  1. I know that I exist.

  2. I know that the sky is blue.

  3. I know that 2 + 2 = 4.

  4. I know that Paris is the capital of France.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The statement 'I know that I exist' is an example of an epistemic necessity because it is a statement that is necessarily true for me, given my own experience.

Multiple choice

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

  1. The sun is a star.

  2. The sky is blue.

  3. I am thinking.

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

The statement 'The sky is blue' is an example of a contingent truth because it is a statement that could be otherwise. It is conceivable that the sky could be a different color, such as green or purple.