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 contrapositive of the statement "If A, then B"?

  1. If ¬B, then ¬A

  2. If B, then A

  3. If ¬A, then ¬B

  4. If A, then ¬B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The contrapositive of a statement is the statement that is formed by negating both the hypothesis and the conclusion.

Multiple choice

What is the converse of the statement "If A, then B"?

  1. If ¬B, then ¬A

  2. If B, then A

  3. If ¬A, then ¬B

  4. If A, then ¬B
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The converse of a statement is the statement that is formed by interchanging the hypothesis and the conclusion.

Multiple choice

What is the inverse of the statement "If A, then B"?

  1. If ¬B, then ¬A

  2. If B, then A

  3. If ¬A, then ¬B

  4. If A, then ¬B
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The inverse of a statement is the statement that is formed by negating the hypothesis.

Multiple choice

Which of the following is an example of a logical fallacy that can weaken a counterargument?

  1. Ad hominem

  2. Straw man

  3. Red herring

  4. Circular reasoning
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Ad hominem, straw man, red herring, and circular reasoning are all examples of logical fallacies that can weaken a counterargument by employing faulty logic or irrelevant information.

Multiple choice

Which of the following is an example of a logical fallacy that can weaken a rebuttal in a political debate?

  1. Ad hominem

  2. Straw man

  3. Red herring

  4. Circular reasoning
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Ad hominem, straw man, red herring, and circular reasoning are all examples of logical fallacies that can weaken a rebuttal by employing faulty logic or irrelevant information.

Multiple choice

Which of the following is an example of a deductively valid argument?

  1. All dogs are mammals. Some mammals are cats. Therefore, some cats are dogs.

  2. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  3. Some dogs are black. All black things are evil. Therefore, some dogs are evil.

  4. All cats are furry. Some furry things are dogs. Therefore, some dogs are cats.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A deductively valid argument is one in which the conclusion necessarily follows from the premises. In the given argument, the premises "All dogs are mammals" and "All mammals are animals" logically imply the conclusion "All dogs are animals".

Multiple choice

Which of the following is an example of a deductively invalid argument?

  1. All dogs are mammals. Some mammals are cats. Therefore, some cats are dogs.

  2. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  3. Some dogs are black. All black things are evil. Therefore, some dogs are evil.

  4. All cats are furry. Some furry things are dogs. Therefore, some dogs are cats.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A deductively invalid argument is one in which the conclusion does not necessarily follow from the premises. In the given argument, the premises "All dogs are mammals" and "Some mammals are cats" do not logically imply the conclusion "Some cats are dogs".

Multiple choice

Which of the following is a necessary condition for a deductive argument to be valid?

  1. The premises must be true.

  2. The conclusion must be true.

  3. The premises must be relevant to the conclusion.

  4. The argument must be in a standard logical form.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For a deductive argument to be valid, the premises must be relevant to the conclusion. This means that the premises must provide evidence or support for the conclusion.

Multiple choice

Which of the following is a sufficient condition for a deductive argument to be valid?

  1. The premises must be true.

  2. The conclusion must be true.

  3. The premises must be relevant to the conclusion.

  4. The argument must be in a standard logical form.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A deductive argument is valid if it is in a standard logical form, such as a syllogism or a conditional argument. This means that the argument has a specific structure that guarantees the conclusion follows from the premises.

Multiple choice

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

  1. All dogs are mammals. Some mammals are cats. Therefore, some cats are dogs.

  2. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  3. Some dogs are black. All black things are evil. Therefore, some dogs are evil.

  4. All cats are furry. Some furry things are dogs. Therefore, some dogs are cats.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A deductive argument is one in which the conclusion necessarily follows from the premises. In the given argument, the premises "All dogs are mammals" and "All mammals are animals" logically imply the conclusion "All dogs are animals".

Multiple choice

Which of the following is a necessary condition for a deductive argument to be sound?

  1. The premises must be true.

  2. The conclusion must be true.

  3. The premises must be relevant to the conclusion.

  4. The argument must be in a standard logical form.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For a deductive argument to be sound, the premises must be true. This means that the premises must accurately represent the facts of the situation.

Multiple choice

Which of the following is a sufficient condition for a deductive argument to be sound?

  1. The premises must be true.

  2. The conclusion must be true.

  3. The premises must be relevant to the conclusion.

  4. The argument must be in a standard logical form.
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

A deductive argument is sound if it is both valid and has true premises. This means that the argument must have a structure that guarantees the conclusion follows from the premises, and the premises must accurately represent the facts of the situation.

Multiple choice

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

  1. All dogs are mammals. Some mammals are cats. Therefore, some cats are dogs.

  2. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  3. Some dogs are black. All black things are evil. Therefore, some dogs are evil.

  4. All cats are furry. Some furry things are dogs. Therefore, some dogs are cats.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A deductive fallacy is an argument that is not valid. In the given argument, the premises "Some dogs are black" and "All black things are evil" do not logically imply the conclusion "Some dogs are evil".

Multiple choice

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

  1. All dogs are mammals. Some mammals are cats. Therefore, some cats are dogs.

  2. All dogs are mammals. All mammals are animals. Therefore, all dogs are animals.

  3. Some dogs are black. All black things are evil. Therefore, some dogs are evil.

  4. All cats are furry. Some furry things are dogs. Therefore, some dogs are cats.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A deductive argument is one in which the conclusion necessarily follows from the premises. In the given argument, the premises "All dogs are mammals" and "All mammals are animals" logically imply the conclusion "All dogs are animals".

Multiple choice

Which of the following is a necessary condition for a deductive argument to be sound?

  1. The premises must be true.

  2. The conclusion must be true.

  3. The premises must be relevant to the conclusion.

  4. The argument must be in a standard logical form.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For a deductive argument to be sound, the premises must be true. This means that the premises must accurately represent the facts of the situation.