The Signature Without the Name is a working research program deposited as one half of a σύμβολον — a broken token whose halves authenticate by fitting. It asks whether Sappho 31 is findably present in Philo of Alexandria, and answers in two registers: the name is absent, and the apparatus is not.
A diacritic-blind census of the full 31-work Greek Philo corpus (2,808,000 normalized characters) returns zero occurrences of the poet's name; all four string-hits are σάπφειρος, the sapphire — a green stone, engraved, and the pavement beneath God's feet. The null is confirmed on a second, non-identical corpus. What is present is the poem's machine: Mut. 54–57 parsing Abraham's fall into the channel catalogue, each station carrying its occlusion and its reactivation-by-another; Migr. 47–48 stating the media crossing as doctrine — the people saw the voice, not heard it; and Quis Heres 249–266 supplying a point-for-point collation in which simultaneity becomes alternation, the causal arrow flips so that occlusion gates reception, the catalogue compresses to one setting luminary, and the poem's agentless terminus is answered by an agentless passive from which displaced agency is derived. Two rare-word bridges join Philo to Longinus at the transmission joints: δυσεξάλειπτος at Spec. 1.106 and ὑψηγορία at Det. 79.
The program's contribution is methodological. It specifies the claimed relation as an executable transform and tests it by blind reconstruction: five substrates received the specification and the Greek source in fresh threads, with no target named and no translation supplied, and produced Greek. All five reconstructed the target's structural complex; one retrieved rather than derived and was detected on surface evidence alone — a Septuagint spelling it did not use, a taxonomy exceeding its own logged census, an adverb no rule motivates.
The report discloses two failure modes the method found in itself. Attestation induction: asking a substrate to declare recognition creates the recognition, so the rule was withdrawn. Specification leak: three of the author's own rule-glosses proved to be English renderings of the target's Greek, discounting three rubric points to unproven pending re-run. The governing rule is stated throughout — convergence at a slot the specification determines is not evidence of anything except that the specification is executable.
What is established is a mapping, not a presence: sufficiency, not specificity. The target-arm control has not been run; the historical claim remains modular; the relay through Plato is stated at full strength as the live alternative it is.
The sealed evaluator rubric, the target register, the pre-registered predictions for unrun experiments, and the inverse run's order key are held in a private counterpart whose SHA-256 is published here. Neither half is operative alone: a prediction filed after a run is not a prediction, and a rubric a substrate can read cannot blind-score that substrate. The separation is pre-registration discipline implemented so that it survives a public, machine-findable archive — and its limit is stated rather than concealed.