Justified True Belief

Justified true belief mistakes a psychological state for an epistemic status.

The traditional definition of knowledge holds that knowledge is justified true belief (JTB). In this view, a person knows a proposition if it is true, they believe it, and they have sufficient justification for that belief.

The standard objection to JTB is the Gettier problem: cases where a belief is true and justified, yet clearly not knowledge. That objection is based on insufficiency. The argument here is about a more fundamental problem: even without Gettier cases, justification and belief are the wrong kinds of concepts for grounding knowledge.

Category Error

JTB defines knowledge by combining three elements: belief, justification, and truth. Belief and justification are features of a person's cognitive state. Truth, by contrast, is a property of propositions relative to reality.

Belief and justification describe why someone holds a claim; they are psychological and social facts about a knower.

Truth describes whether the claim itself corresponds to reality. It is independent of who believes it.

Epistemic status is not a feature of mental states. It is a feature of explanations: whether they successfully account for reality and withstand criticism.

A belief can be:

• justified without being true
• true without being justified
• both justified and true without explaining anything

None of these cases amount to knowledge.

Justification and belief are the wrong kinds of concepts to evaluate.

Therefore, defining knowledge in terms of belief and justification is a category error.

Justification Does Not Track Truth

Justification concerns reasons for believing, not reasons why something is true.

A belief may be well-justified, sincerely held, socially endorsed, and still be false. A belief may have no explanatory ground and still be true. The JTB theory has no method to distinguish between these.

Justification Terminates Arbitrarily

Every chain of justification faces three possible outcomes:

1. Infinite regress: each reason calls for another, and the chain never ends
2. Circularity: a belief is justified by an appeal that eventually returns to itself
3. Dogma: the chain stops at an unexamined assumption declared self-evident

This is the Trilemma of Justification.

Justification explains belief. It does not explain reality.

Truth Is Not Accessible by Justification

Whether a claim is true is independent of whether it is justified.

Knowledge must be robust under counterfactual variation. A claim that is true only by coincidence will fail under nearby possible conditions. Explanations answer why the claim would still hold (or fail) if things had been different.

Justification cannot answer the question: "if things had been different, would this claim still be true?"

Without that capacity, justification cannot distinguish knowledge from circumstance.

Knowledge as Explanation

Knowledge is not justified true belief. It is explanatory connection to reality.

An explanation has epistemic status when it:

• accounts for what is observed
• survives attempts at refutation
• remains robust under counterfactual variation

This is not a matter of psychological certainty or social consensus. It is a matter of whether the explanation successfully captures the structure of reality.

2025-09-29 Aaron Brinton
2026-01-06 extracted from Knowledge; edits for context