Singularities as Bookkeeping Boundaries: Over-Constraint, Temporal Extendability, and Domain Reconciliation Between GR and QFT

Singularities in general relativity are routinely interpreted as physical objects—points of infinite density or locations where “physics breaks.” This paper argues instead that singularities are bookkeeping boundaries: markers of the termination of admissible, recoverable description under the assumptions of matter-bearing, temporally extendable spacetime. Using causal boundary structure in the style of Penrose conformal reasoning, we show that singularities should be treated as limits of temporal extendability and structural recoverability, not as ontological entities. This reclassification dissolves several long-standing paradoxes (infinite density, “inside” questions, and horizon drama) by identifying them as category errors. We conclude by reconciling general relativity and quantum field theory as distinct domain theories: GR governs large-scale causal geometry and boundary structure, while QFT governs local excitations within an already-admissible causal manifold. The apparent conflict is reduced to domain mismatch rather than a fundamental inconsistency.