Black Hole Mass as a Structural Invariant of Realization

This work presents an empirical test of a foundational question in observational physics: whether an inferred quantity reflects an intrinsic physical structure or is contingent on the specific realization pathway by which data are rendered observable. We introduce and formalize the principle of realization mirror invariance, which states that a genuine physical observable must remain invariant under different, physically equivalent realization procedures applied to the same underlying data. A failure of such invariance would indicate a procedural artifact rather than a structural property. The principle is tested using JWST/NIRSpec observations of a z ≈ 9 “Little Red Dot” galaxy, focusing on black hole mass estimates derived from the broad Hβ emission line. Two distinct realization pathways are constructed from identical calibrated two-dimensional spectral data: a pipeline-equivalent extraction and an independent direct realization from the same inputs. Across multiple fitting windows, masking strategies, and exposures, the inferred broad-line widths—and hence the black hole mass proxy—are shown to be statistically invariant, with paired differences consistent with zero within bootstrap confidence intervals. This invariance demonstrates that the measured black hole mass is not an artifact of data reduction order, window selection, or realization details. Instead, it behaves as a structural invariant of the system. We interpret this result as evidence that black holes are best understood not as dynamically assembled objects in the conventional sense, but as structural residues of completed realization, whose observable properties reflect the closure of realizable structure rather than the specifics of observational procedure. The findings provide a natural explanation for the early emergence of massive black holes in the high-redshift universe and motivate a broader reinterpretation of gravitational collapse as a process of structural completion rather than accretion-driven growth. More generally, realization mirror invariance offers a domain-independent diagnostic for assessing the physical meaning of inferred quantities in observational science.