Deductive and Inductive Flashcards

A researcher observes that every swan she has ever seen is white and concludes 'All swans are white.' What type of reasoning is this?

Answer: Inductive reasoning

This is inductive reasoning because the conclusion generalizes beyond the observed cases to all swans.

Which of the following is a valid deductive argument form?

Answer: If P then Q; P is true; therefore Q is true

Modus ponens (If P then Q; P is true; therefore Q is true) is a valid deductive argument form that guarantees the conclusion.

A detective reasons: 'The crime occurred between 8 and 10 PM. Mr. Smith has a verified alibi for that entire period. Therefore, Mr. Smith did not commit the crime.' This is:

Answer: Valid deductive reasoning from established premises

Given the premises are true, the conclusion follows necessarily — this is valid deductive reasoning.

Which feature BEST distinguishes a strong inductive argument from a weak one?

Answer: The evidence makes the conclusion highly probable

A strong inductive argument provides evidence that makes the conclusion highly probable, not certain.

Consider: 'No mammals are cold-blooded. All dolphins are mammals. Therefore, no dolphins are cold-blooded.' This argument is:

Answer: Valid and sound if premises are true

The argument is valid (conclusion follows necessarily from premises) and sound (both premises are true).

Which scenario demonstrates the fallacy of affirming the consequent?

Answer: If it rains, the ground gets wet. The ground is wet. Therefore it rained.

Affirming the consequent incorrectly assumes that because Q is true, P must be true in an 'If P then Q' structure.

An inductive generalization is considered cogent when:

Answer: Its premises are true and the argument is strong

A cogent inductive argument is both strong (makes the conclusion probable) and has true premises.