Argument from Ignorance | Who Has to Prove What | Evidentia

Argument from Ignorance

F106 • Informal - Evidence

Also known as: Ad Ignorantiam, Appeal to Ignorance

Difficulty 2/10Medium LoadVery Common

Definition

Claiming something is true because it hasn't been proven false, or false because it hasn't been proven true.

Why Invalid

Absence of evidence is not necessarily evidence of absence. Not having proof one way doesn't establish the opposite.

Edge Cases

Legal contexts: presumption of innocence
After exhaustive search in closed domain
When we should have found evidence if claim were true

Examples

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Scope of Applicability

Check if conclusion based on lack of evidence
Determine if absence of evidence treated as evidence
Assess if all reasonable investigation has been done

Common Mistakes

Not recognizing legitimate uses
Confusing with burden of proof
Not considering if absence of evidence is expected vs unexpected

Burden of Proof FallacyHistorical Inevitability

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F105 Burden of Proof Fallacy F107 Moving the Goal Posts

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