Complementarity Without Duality

This paper shows that complementarity does not require duality, opposition, or mutually exclusive ontologies. When admissibility and constraint envelopes are enforced, complementary descriptions are revealed as internal, non-conflicting re-descriptions within a single admissible representational regime, rather than as competing or irreducible alternatives. The analysis demonstrates that traditional dualities—wave/particle, classical/quantum, observer/system—arise from misclassifying envelope-internal variation as cross-envelope incompatibility. Once envelope non-contact is respected, these pairs no longer stand in tension. They are complementary only in the sense that they license different internal descriptions under different fixation choices, without implying ontic division. The result removes the need for dualistic interpretation while preserving the explanatory role of complementarity. No synthesis, unification program, or interpretive framework is proposed. The paper records a structural clarification: complementarity is admissible without duality, and apparent oppositions dissolve once admissibility boundaries are made explicit.