Index of Absent Referents

The Index of Absent Referents is a bound register, presently one hundred and forty-one volumes, maintained on the Ninth Spire by the Office of Unfilled Slots and listing every referent which the Tower has formally determined to be absent. It is not a list of missing things. A referent enters the Index only after a finding of absence has been made and sealed, and it leaves the Index only when it is found; in practice, the second column is mostly empty.

The Index is frequently confused with the Chamber of Latent Referents, which holds subjects that have not yet arrived, and with the Registry of Terminal Referents, which holds subjects that cannot arrive. The Index of Absent Referents holds subjects that were expected, were found not to be present, and whose absence was entered as a fact in its own right — a distinction first drawn in the Manual of Concrete Referents, Book III, which describes absence as "a condition of the slot and not of the thing" (Manual of Concrete Referents, Book III, §12).

Origin and the Ninth Spire

The Index was opened in the winter of the year the Survey of Absent Elevations returned without conclusions, when the surveyors found themselves unable to file their report because the report's own subject matter had no register. The Office of Unfilled Slots was created that same winter to receive it, and its first act was to enter the Survey itself, at folio 1, where it remains.

Entries are made in iron-gall ink on laid paper and require two signatures: the clerk who observed the absence and the clerk who confirms that the slot was properly made. A third signature, from the Bureau of Ambiguous Forms, is required where the absent referent might reasonably be confused with an Identical Ambiguous Referent, a category that has caused more delay in the Office than any other.

Method of entry

Each entry records the referent's designation, the date and floor of the observation, the dimensions of the slot it failed to occupy, and a short description in the negative. The description is not permitted to describe the absent referent positively; it may describe only what was expected and where. The rule was tightened after the Catalogue of Negative Descriptions admitted an entry reading "a large, brown, patient animal" and was obliged to strike it, the phrase being held to constitute a description of a thing rather than of an absence.

The Index is consulted daily by the Desk of Concrete Referents, which draws on it whenever an entry in the Manual of Concrete Referents lacks material substantiation, and by the Index of Ambiguous Precedents, which cites it in disputes over classification.

"An absence is not a vacancy. A vacancy may be filled by anyone; an absence is particular to one thing and to no other, and persists after the thing is found."

— Concordance 12 (The Principle of Terminal Referents), Annex 3

Dispute: the status of found referents

The chief scholarly quarrel concerns what happens when an absent referent is found. Concordance 12, Annex 3, holds that the absence persists and must remain on the register, struck through but legible. The Concordance of Recovered Slots, promulgated some four decades later, holds the opposite: that an absence is extinguished by the presence of the thing, and that the Index should be corrected rather than annotated.

The Office has never resolved the matter and has adopted the practice of striking entries through in red and leaving them in place, which satisfies neither document. In the case of the Perpetually Absent Goat — struck through at folio 8,412 and again at 8,413 — the Office maintains two struck entries and one unstruck, the unstruck one having been entered after the Great Re-Cataloguing of the Perpetually Absent Goat returned the animal to absent status. The Index of Superseded Clauses records the resulting annotation at Appendix Gamma-7 as "Absent, Presumed Functional."

The borders dispute of the Eleventh Spire

Between the years recorded as 6,204 and 6,241 the Index was embroiled in a jurisdictional quarrel with the Chamber of Latent Referents over referents that were absent but also forthcoming. The Chamber maintained that such referents belonged to it, being not yet due; the Office maintained that they belonged to the Index, being not yet present. The Silent College ruled in 6,239 that absence precedes lateness, and that the Index has first claim on any referent whose slot has been made but not occupied. The Chamber has complied since 6,241, though its clerks continue to annotate the reverse of their own entries with the words "on loan to the Ninth," a practice the Office has chosen not to notice.

Notable holdings and current practice

The Index is closed to visitors on the second and fourth days of the week, when the shelves are dusted. Beyond that, the holdings most often requested are:

• Folio 1 — the Survey of Absent Elevations (WA-102), absent elevations 1 through 47.
• Folio 8,412 — the Perpetually Absent Goat, struck through twice.
• Folio 22,009 — the Choir of Absent Voices, entered under its sub-index at Annex Sigma of Directive 14,899-δ, with the note "audible; not present."
• Folio 39,776 — the Unattributed Footfall, heard on the stairs between Floors 611 and 612, never attributed.

The Office's current clerk of first signature, Marden Vey, has served since the year of the borders ruling and has entered more absences than any of her predecessors. Her standing grievance, recorded in the Office's minute-book for the fourth day of the week, is that the Index has no volume for absences of the Index itself; she has requested one for eleven years without reply. The request remains open, and is not indexed.