Questions: The Justified True Belief Account of Knowledge

Question 1

Maria believes it is raining because she sees water on the sidewalk — though the water came from a burst pipe, not rain. It is actually raining elsewhere in the city. Which JTB condition does Maria's belief fail?

• A. The truth condition — her belief is false
• B. The belief condition — she doesn't really believe it
• C. The justification condition — her evidence doesn't properly support the belief
• D. None — this is a genuine case of knowledge

Answer: (C)

Maria's belief is true (it is raining in the city) and she believes it, but her justification is defective — she infers rain from evidence (wet sidewalk) that is actually caused by a burst pipe. Her belief is true and believed but not properly justified by the evidence available to her. This type of case is structurally close to the Gettier counterexamples.

Question 2

According to the JTB account, if your belief is justified, it should be true.

• T. True
• F. False

Answer: False

Justification and truth are independent conditions. You can have excellent justification for a belief that turns out to be false — a doctor carefully examining symptoms may be fully justified in a diagnosis that is nonetheless wrong. JTB requires all three conditions to hold simultaneously; justification alone does not guarantee truth.

Question 3

What work does the 'justification' condition do in the JTB analysis — what cases does it rule out that truth and belief alone would allow in?

Model answer: Justification rules out true beliefs held for bad reasons or by sheer luck — for example, a broken clock that happens to show the right time. Without justification, any true belief would count as knowledge, even one formed by guessing, wishful thinking, or coincidence.

The justification condition distinguishes knowledge from lucky true belief. If you guess that a coin will land heads and it does, you had a true belief but not knowledge — you had no principled reason to expect that outcome. Justification requires that your belief be based on good evidence or reliable reasoning: something that connects your belief to the truth in a non-accidental way.