Concordance 7, Revision 4, Clause 19

Concordance 7, Revision 4, Clause 19 is the provision governing the tabulation of undocumented floors during spiral survey, and the sole clause of the Seventh Concordance, Revision 4 to have attracted a standing interpretive dispute lasting more than four hundred years. It is sometimes called the Silent Tabulation, though no text ratified at Revision 4 uses that phrase; the name originates in the marginalia of Surveyor Halven Rees, who annotated his working copy on Floor 1088 and whose notes were catalogued, at his own request, before his boots were.

The clause runs, in the ratified text: "Where a spiral survey records a floor for which no number is returned, the floor shall be entered at zero and counted once. No floor shall be counted twice in the same survey." Revision 4 was ratified under Clause 33, Annex Delta on 19 Sable 441, and Clause 19 has not been re-engrossed since, though it has been amended twice by later instruments that do not describe themselves as amendments.

Text and immediate context

Clause 19 sits between Clause 18 — codifying the Dilemma of Concurrent Verity — and Clause 20, which concerns the disposition of surveyor's chalk. The placement is thought to be deliberate. The Dilemma establishes that two witnesses of equal standing may not both be wrong; Clause 19 establishes what to do when the building itself declines to answer. Read together, the two provisions produce the result that an unnumbered floor is neither confirmed nor denied, but merely counted, and counted once.

The tabulation form ratified alongside the clause provides four ruled columns and one unruled one. The unruled column is the subject of a standing circular from the Bureau of Perpetual Revision, which asks that surveyors not write in it and does not state what happens if they do. Surveyors write in it. The Bureau has collected these entries since 612 and catalogues them under Class 9, Retrospective Acknowledgements, where they are filed without comment.

"Zero is a quantity and not an absence. A floor entered at zero is a floor that was there and has declined to say so. Enter it, once, and proceed downward without argument."

— Seventh Concordance, Revision 4, Clause 19, explanatory schedule

The Halven Rees dispute

In the winter of 457, during the Seventh Spiral Survey chartered under Clause 17 of the Fourth Revision, a descent party under Halven Rees recorded eleven floors in sequence that returned no number. Rees entered all eleven at zero, as the clause requires. The party's second surveyor, Surveyor Miren Cassal, argued that the clause counts floors rather than entries, and that eleven floors entered at the same value are counted eleven times and therefore zero times, since the value carries no distinction between them. Cassal's reading — known as the null-collapse reading, or Cassal's Sum — was entered into the record and then, by Rees's hand, entered again.

The dispute turned on the word "once." Rees held that once means one entry per floor; Cassal held that once means one floor per value, which would reduce the entire unnumbered descent to a single floor and the survey to a total of nothing. Rees's reply, recorded verbatim in the survey log, was: "Then we have descended a floor that is not a floor, and I have walked down its stairs." The Office of the Receiver of Irregularities, established under the Third Concordance, Clause 37, Third Revision, declined jurisdiction on the grounds that the irregularity was numerical rather than material, a distinction later criticised in the Annex of Perpetual Revision.

The question was referred to the Directorate of Contextual Reconciliation, which applied the doctrine of contextual density first established at the same Revision and returned a finding that the clause had been drafted with a density of 0.4 — below the threshold at which contradiction is considered to have occurred. The finding is widely quoted and widely resented.

Position on indexical integrity

Because Clause 19 governs floors that cannot be numbered, its interaction with the sequestration provisions has been uneasy. Clause 812 of the same Revision provides the framework for whole-spiral sequestration where a spiral's indexical integrity is threatened, and Clause 19's zero-entry appears, on a plain reading, to preserve indexical integrity by declining to assert anything at all. The Directorate has held since 588 that a zero entry is an assertion of the strongest kind, being the assertion that a number exists and will not be produced.

Under this reasoning, a spiral containing unnumbered floors recorded at zero is not sequestered but is held in what the Directorate calls "standing abeyance," a condition that requires no action, permits no correction, and is not recorded anywhere except in the abeyance register, which is kept on a floor the register does not number. The Twelfth Concordance's ash-rendering provision has been invoked three times against abeyance registers and has failed each time, since the provision addresses documents and the register's entries are ruled, by Clause 19, to be quantities.

Later instruments and the scroll question

Two instruments have altered the clause's practical operation without amending it. The first is Revision 9.4, which requires surveyors to state the zero in words as well as in figures; the required form is "zero, observed," and it must be spoken aloud at the threshold. The second is the Annex Γ Revision, which restricts the copying of unnumbered entries between survey ledgers and has produced a small class of ledgers in which the entries are known to have existed and cannot be found.

Clause 19 is not subject to the prohibition at Seventh Concordance, Revision 12, Clause III, which bars full physical access to the index scroll of the Spool of Revision, but surveyors have noted that a scroll of zero entries and a scroll that has been sealed both return nothing to the hand. The Chamber of Fading Impressions has requested the difference be ruled upon. The request is in abeyance.

Practical observance

Current practice on descending parties follows Rees rather than Cassal, largely because Cassal's Sum, if applied, ended every survey in which it was tried and several in which it was not. Surveyors enter each unnumbered floor at zero, in ink, once, without argument, and state the words at the threshold. The unruled column is left empty. Boots are removed before the chalk cabinet on Floor 1088 and may be collected on the way back, if the way back is numbered.