One level up, the ACH/abduction and Lucky-Widrow notes are a real bridge: both instantiate the argument-from-silence method, which part of the philosophical literature classifies as abductive reasoning

argument-from-silenceabductive-reasoningjingle-fallacyembedding-false-friendbridge-investigationepistemologymcgrewliptonwaltonachluckywidrow

observation-ach-abduction-lucky-widrow-cosine-pairing-is-embedding-false-friend confirms no connection between the two notes' actual subject matter. But the two notes are not just independently disjoint claims — each is the vault's own instance of the same reasoning move: claim-no-primary-source-documents-ach-abduction-similarity reasons from Heuer's, the CIA's, and one peer-reviewed study's silence on abduction to a negative finding about ACH's claimed origin; claim-lucky-widrow-independent-origination-favored-lucky-side-unverified reasons from the silence in Lucky's 1965 bibliography to a positive finding about independent invention. Both are graded on moc-argument-from-silence's ledger, and both already link to that hub independently, without linking to each other.

That shared method has a name in part of the philosophical literature: per claim-lipton-construes-argument-from-silence-as-inference-to-best-explanation, Lipton (and Sinnott-Armstrong & Fogelin) construe the argument from silence as an instance of inference to the best explanation — the modern descendant of Peircean abduction. On that reading, the vault's own recurring negative-finding method is abductive reasoning, by name, confirmed at Tier 1. (A rival classification exists too — claim-walton-classifies-argument-from-silence-as-argument-from-ignorance — so the label is contested, not settled.) The bridge sits one level up from where the topic pairing first suggested it: not "ACH resembles abduction" (still unconfirmed) and not "Lucky's equalizer resembles LMS via abduction" (no such claim exists), but "the vault's own method for reaching both findings is, in part of the literature, abductive reasoning."