Fallibility

Fallibility is the possibility of being wrong.

An entity is fallible if it is possible that it holds at least one false belief. It concerns what could be the case, not what is the case. A fallible entity may hold entirely true beliefs and still be fallible.

Properties

Fallibility:

• is structural, not a defect of carelessness or ignorance
• is modal, not actual: you are fallible even if you happen to be right
• is a counterfactual property: there exist conditions under which a held belief would be false
• is binary: an entity is either fallible or infallible

Fallibility does NOT:

• imply weakness or incompetence
• require actually being wrong

No belief is beyond the reach of criticism. No method is immune to failure. No conclusion is guaranteed.

Certainty

Certainty is the state of holding a belief beyond the possibility of error.

If fallibility is the possibility of being wrong, then certainty is its denial. To be certain is to claim that error is not merely absent but impossible.

Fallibility precludes certainty. A fallible entity cannot achieve a state in which error is ruled out. This is not a psychological limitation (lack of confidence) but an epistemic one (the structure of finite cognition).

2023-11-30 Aaron Brinton
2026-01-28 extracted from Universal-Fallibility; edits for context