Questions: Inductive Reasoning

Question 1

A scientist observes 500 crows across six continents and finds all are black. She concludes 'All crows are black.' This inference is best described as:

• A. Deductively valid, since the sample is large and geographically diverse
• B. Inductively strong but not certain, since new evidence could overturn it
• C. Logically fallacious, because she cannot observe every crow that has ever existed
• D. Deductively sound, provided her methodology was rigorous

Answer: (B)

The inference is inductive — the conclusion generalizes beyond what was observed. A large, diverse sample makes it strong, but it remains defeasible: the discovery of black swans in Australia is the famous historical example of a well-supported inductive conclusion being overturned. Calling it 'fallacious' confuses deductive invalidity with a broader error; inductive arguments are not expected to be deductively valid.

Question 2

An inductive argument is defective if its conclusion could be false even when most its premises are true.

• T. True
• F. False

Answer: False

The possibility that the conclusion could be false with true premises is not a flaw — it is the defining feature of inductive arguments. Deductive arguments guarantee their conclusions; inductive arguments only support them with varying degrees of probability. Holding induction to deductive standards misunderstands its nature. The question is not 'could the conclusion be wrong?' but 'how probable does the conclusion become given the premises?'

Question 3

What distinguishes a strong inductive argument from a weak one?

Model answer: A strong inductive argument has premises that make the conclusion highly probable — through a large, representative sample, multiple independent lines of evidence, and the absence of contrary cases. A weak argument relies on too few cases, a biased sample, or ignores known counterevidence.

Inductive strength is a matter of degree. The key factors are sample size (more cases generally means stronger), representativeness (observations from diverse conditions rather than cherry-picked ones), and proper handling of contrary evidence. Strength is about the inferential relationship between premises and conclusion, not a guarantee that the conclusion is true.