A dialetheia is a genuinely true contradiction: a proposition P and its negation, both true — not because the language is defective, but because the subject matter forces it. Its parameters are: (1) the contradictory pair — canonical candidates are the Liar sentence, true only if false, and Russell set, which contains itself only if it does not; (2) the domain — semantic paradoxes, and certain legal or institutional contradictions argued to be real; (3) the accompanying logic — a paraconsistent system (e.g. Priest LP) that admits true contradictions while restricting ex contradictione quodlibet, so that truth and falsity do not explode into triviality. It persists as a standing position in philosophical logic: the dialetheist view is maintained through paraconsistent reasoning, formal semantic analysis, and ongoing debate over the classical law of non-contradiction. [formal: Greek dialytheia "utter destruction" | substrate: mind | horizon: generations | explicit: yes | epoch: 0.3]
Accepted ontology entry
dialetheia
A dialetheia is a genuinely true contradiction: a proposition P and its negation, both true — not because the language is defective, but because the subject matter forces it. Its parameters are: (1) the contradictory pair — canonical candi…
Definition
Why it is in scope
A dialetheia is the human-made concept of a statement that is both true and false — a genuinely true contradiction. It persists through philosophical logic as a challenge to the classical law of non-contradiction, maintained by the practice of paraconsistent reasoning and formal semantic analysis.
Names and aliases
- dialetheiaen · CANONICAL
Relations from this entry
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Dialetheia (the philosophical position that some statements can be both true and false) was formalized within paraconsistent-logic. Paraconsistent-logic existed first (da Costa, 1950s-70s) and fed into the concept of dialetheia as developed by Priest and others. Law 7: which came first — the logic framework predates the specific philosophical position.
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Dialetheia IS a specific kind of paradox — a statement or proposition that is both true and false. Competent-speaker test: 'a dialetheia is a kind of paradox.' Paradox is the nearest kind.
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Record identity
- Created
- Jul 30, 2026, 10:40 AM UTC
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- f70af3ba37f2577926a735033a0032720fe2b8ed85e54b03596bfb7dfc232d36