Anticipatory Omissions

Anticipatory Omissions are absences recorded before the thing absent has been established as absent, and in some readings before it has been established as a thing. They are administered jointly by the Bureau of Quantitative Esoteria and the Materials Board, and are the only class of omission for which a filing may lawfully precede its own subject. Gaps of this kind are entered in a distinct hand (a pale iron-gall, rust-brown on ageing) at the rear of the Logbook of Omissions, which reserves leaves 1,061 through 1,140 for the purpose and has never filled more than forty-one of them at once.

The class should not be confused with the Anticipatory Entries proper, which concern subjects expected and then supplied. An Anticipatory Omission concerns subjects expected and then not supplied — or, in the harder cases, subjects never expected at all, whose absence is noticed only after the anticipation has quietly expired.

Origin and the Winter of the Unentered Shelf

The practice is usually dated to the winter of the Tower's year 1,142, when a junior cataloguer of the Materials Board, Ilse Vantrey, was assigned the re-shelving of Floor 913 (the Corridor of Probable Contents) and found that forty-one of its cases were empty. No requisition existed for their contents. No withdrawal had been sealed. The cases themselves bore labels in a hand no one in the department admitted to recognising, and the labels named works that had never been commissioned, never been lent, and never been reported missing.

Vantrey's report of 2 Frostfall, 1,142, filed under the title On Certain Empty Cases and Their Evident Fullness, argued that the cases were "not vacant but vacated, and vacated in advance" (Vantrey, Board memorandum 913/7). The Materials Board accepted the finding and referred the matter upward. What returned was not a ruling but a form.

Instrumentation

Anticipatory Omissions are detected by the Anticipatory Phantom apparatus installed at the head of each participating stairwell, which registers a faint load where no leaf is present. A positive reading is called a pre-absence, and is logged with the aperture and spiral marking of the housing in which it occurs. The readings are then plotted on the Axis of Omissions between the ordinary gap positions and the theoretical poles Θ and Θ, though the Anticipatory band itself has no agreed coordinate and is usually shown as a bracketed interval.

Calibration is a standing difficulty. Because the Index of Regrettable Omissions is cross-referenced daily against newly filed gap reports, and because an Anticipatory Omission is by definition not yet a gap report, the two instruments can drift apart by as much as nine weeks. The Bureau's remedy has been to treat drift as a species of evidence rather than error, a position set out in Doctrine of Anticipatory Resonance and never formally withdrawn.

Contradiction of the Concordances

Two instruments govern the class, and they disagree.

"An omission may not be recorded before the omission has occurred; a record made earlier is a prediction, and predictions are not omissions."

— Fourth Concordance, Annex 2, Clause 6

"Where an absence is anticipated with sufficient regularity, the anticipation shall stand as the record, and the absence, when it arrives, shall be entered only as confirmation."

— Seventh Concordance, Annex 1, Clause 3

The Concordance of Anterior Filing attempted in 1,204 to reconcile the two by distinguishing recorded omissions from registered ones, but its own Appendix C defines registration as "the act of recording," and the attempt collapsed. The Bureau of Quantitative Esoteria continues to follow the Seventh; the Materials Board follows the Fourth; the Logbook of Omissions is recalibrated quarterly against the Index and annually against the Registry of Omissions in a manner that satisfies neither.

A further dispute concerns whether Anticipatory Omissions are properly a subdivision of the Class 1: Ambiguous Omissions catalogued under Con. 14, Annex Σ-IV, Subsection 1, or a separate class altogether. The Board holds the former; the Bureau, which has never accepted the existence of Class 1 as a category distinct from its own bands, holds nothing at all and returns the question unendorsed.

The Barstaw Grievance

In 1,219 the clerk Osric Barstaw, then second registrar of the rear leaves, filed a complaint of forty pages concerning the retrospective amendment of Anticipatory Omissions. Barstaw's contention was simple: an entry had been made anticipating that a certain atlas would prove absent, the atlas had subsequently been found present, and the entry had then been amended to describe the atlas's binding rather than its absence — without, in his words, "the courtesy of a fresh leaf" (Barstaw, Grievance 19, fol. 3). He asked that amendments to anticipatory entries be given a terminal mark so that the original anticipation remained legible.

The Board declined, on the ground that a terminal mark would imply the anticipation had failed, and an anticipation cannot fail because it has no subject against which to fail. Barstaw was reassigned to Floor 1,004 in the spring. His grievance remains the standard citation for the proposition that an Anticipatory Omission is unfalsifiable, a phrase he did not use and would not have accepted.

Housekeeping

Readers consulting the rear leaves are asked to leave the intervening blank leaves uncounted, as the leaf numbers are assigned and a count disrupts the sequence. Pens are not permitted in the rear leaves; the pale iron-gall is supplied at the desk.

Access to the Anticipatory Omissions band on Floor 913 requires a countersigned pass from the Materials Board and is granted, per standing practice, only to those who have not previously requested it.