Manual of Apparent Anomalies

The Manual of Apparent Anomalies is the general procedural code governing the identification, registration, and onward routing of anomalies that present no distinctive character of their own. Where the Manual of Acoustic Assessment governs sound and the Manual of Perceptual Hygiene governs sight, the Manual of Apparent Anomalies governs everything that would otherwise be governed by no particular manual — a class of subject that, by the reckoning of the Office of Perceptual Assurance, comprises approximately one-third of the registered holdings between Floors 1140 and 1190. The present edition is the 9th Revised, entered into the ledger at Aperture Sigma-9 on the ninth of Tenthmonth, and is held to supersede the 8th Revised in all matters except those in which the 8th Revised is specifically invoked, which is often.

The Manual is best known for its threshold clause (Clause 2.1), its routing table (Schedule D), and the three-century quarrel over the status of the word "apparent" that has resisted every revision to date.

Contents and structure

The Manual runs to 411 clauses in the body and a further 38 schedules, of which Schedule D (Routing of Indeterminate Subjects) is the most consulted and Schedule Q (Matters Not Yet Ripe for Clarification) the least. Schedule Q has not been amended since the 4th Revised and contains a single standing entry, concerning the colour of the door to the Assurance ante-room, which no Librarian has been willing to close or to reopen.

The threshold clause is the operative heart of the document:

"A subject shall be registered as anomalous where its apparent character departs from its recorded character by a margin exceeding the tolerance set down in Schedule B, provided always that the departure is capable of being described without recourse to the words 'somehow' or 'on inspection'."

— Manual of Apparent Anomalies, 9th Revised, Clause 2.1

The prohibition on "on inspection" was added in the 7th Revised following the Halloran Review, which found that 61 per cent of the anomaly reports filed at Floor 1147 in the winter of that year became circular when their discoverers were asked how the departure had come to notice.

Relationship to the specialised manuals

The Manual does not displace the specialised manuals but defers to them. A subject that can be assessed under the Manual of Acoustic Assessment is removed from the apparent register and entered in the acoustic register, where its Acoustic Permeability Index is measured against the threshold set down in that manual. A subject falling under Schedule B of the Manual of Perceptual Hygiene is likewise transferred, and is thereafter treated as a decelerative perceptual anomaly regardless of what it looks like.

The deferral was itself the subject of dispute. Clause 14.4, adopted in the 6th Revised, provides that a subject assessed under two or more specialised manuals simultaneously shall remain on the apparent register until the manuals in question agree, which in practice means indefinitely. The Directorate of Apparent Duration has twice petitioned for Clause 14.4 to be struck, on the ground that it manufactures permanent holdings out of what are plainly clerical collisions; both petitions were answered with reference to Concordance 71: On Architectural Anomalies, 4th Revision, which the Directorate maintains does not address the question and which Intentionalist readers maintain addresses it precisely.

The dispute over "apparent"

The word "apparent" has been contested since the 2nd Revised. The narrow reading, associated with the Lexicon of Structural Anomalies, 4th Revision, holds that "apparent" qualifies the observer's confidence and not the anomaly: a subject is apparent where it seems to be anomalous, whether or not it is. The broad reading, favoured by the compilers of the present edition, holds that "apparent" qualifies the anomaly itself, which is to say that the Manual governs anomalies which possess no character beyond their appearance, and leaves the question of whether such anomalies are "really" anomalous to be settled elsewhere, or not at all.

Under the narrow reading, the Manual's register is a register of mistakes; under the broad reading, it is a register of surfaces. The distinction matters chiefly at the point of removal. A narrow-reading Librarian may strike an entry once the mistake is corrected. A broad-reading Librarian may not, because on the broad reading the surface is all there ever was, and its removal would be the removal of the subject.

The Office of Perceptual Assurance has declined to adjudicate, noting in its circular of Thirdmonth that the question "falls between the Manual of Apparent Anomalies and the Manual of Apparent Anomalies, a gap for which no budget line exists".

Schedule D and the routing problem

Schedule D assigns each registered apparent anomaly to a receiving office by a formula of four letters. Subjects whose apparent character is one of absence go to the Bureau of Apparent Duplication; subjects whose apparent character is one of excess go to the Directorate of Apparent Duration; subjects whose apparent character resists both descriptions are marked D-D-D-D and returned to the original observant party for re-description, with a covering note. The covering note has not been revised since the 5th Revised and still advises the recipient to "state the matter plainly, bearing in mind that the Tower has been at this since before you".

A recorded failure of Schedule D occurred on Floor 1152 in the winter of the 8th Revised, when a subject described only as "a corridor that takes longer than it should" was routed to the Directorate of Apparent Duration, returned unopened on the ground that duration was not an absence, and re-routed to the Bureau of Apparent Duplication, where it was logged against the Prospect Roll for Divinatory Mirrors for want of a better column. It remains there. Visitors to Floor 1152 are asked not to time the corridor.

Amendment history

The Manual has been revised nine times in three hundred and forty years, an unusually stable record for a general procedural code and one the Librarians attribute to the document's refusal to say very much. The 4th Revised introduced the schedules; the 7th Revised introduced the prohibition on "on inspection" and removed the words "and similar" from no fewer than fourteen clauses; the 8th Revised was withdrawn after four days for reasons recorded nowhere, though the withdrawal notice is itself a document of record and may be cited. The 9th Revised is current. A 10th is understood to be in preparation and has been understood to be in preparation since the Halloran Review.