A derivation, once completed, is typically treated as settling the question it was undertaken to answer. This paper argues that this is not generally true, and that the gap between a completed derivation and a settled physical question is easy to overlook precisely because it has no name and leaves no formal trace once crossed. We develop the point through a case in which the gap is unusually visible: a citation, in Hawking’s canonical 1976 physics paper, offered as the source of an extension the citing paper needs but does not itself derive, which turns out oninspection to point to two unsupported sentences in an earlier paper. We use this case not toadjudicate the underlying physical claim, but to isolate two distinct achievements that citationpractice, and derivation itself, can silently conflate: extending a mathematical formalism to abroader domain, and showing that the extended formalism answers a question about a physicalsystem, in the operational sense that connects a model’s terms to what an observer would measure. We argue, drawing on Bridgman’s operational analysis and the model/target-system distinction in philosophy of science, that even a fully executed derivation closing the citation gap we identify would establish the first achievement without thereby establishing the second: a frequency-resolved extension of Hawking’s formalism cannot characterize the polarization structure of the emitted state, and so cannot by itself be used to evaluate the unitarity question the citation is invoked to support, whatever that question’s true answer turns out to be. The dependency this creates is not merely evidentiary but constitutive of Hawking’s own 1976 formal apparatus: that paper’s superscattering operator is built from Hilbert spaces the paper does not construct for the higher-spin sectors, so its own formal question, for those sectors, remains a construction the citation was invoked to supply and does not. We do not argue that this precise structure recurs throughout physics; doing so responsibly would require the same case-by-case verification this paper insists on. We do argue that the case examined here is nota bibliographic curiosity but an instance of a general and underappreciated distinction in whatclosing a derivation can and cannot be shown to achieve.