Doctrinal Drift

Doctrinal Drift is a recognized class of Standard Drift affecting the standing body of rulings, recensions, and procedural interpretations collectively known as the Tower's doctrine. It is distinguished from other drift classes not by cause but by object: where Semantic Drift concerns the meaning of words and Nominative Drift concerns the names attached to things, Doctrinal Drift concerns what the Tower has decided. The distinction is preserved in the definition current since the Chamber of Measured Drift revised its schedules in Year 1,104: "Drift is doctrinal when a reader following the record correctly arrives at a conclusion the record no longer supports" (Ninth Concordance, Annex 2). It is quantified in negative Standard Drift Units (SDUs) and is recorded under the forms catalogued at Protocol Drift and Retroactive Drift.

Classification

A γ-7 form alleging Doctrinal Drift triggers a Substantive Review, a procedure set down in the Fourth Concordance and never successfully amended. The γ-7 is the ordinary instrument of complaint. Any reader who believes a doctrinal text has drifted may file a γ-7 with the floor steward; the steward, having no discretion in the matter, forwards it, and a Substantive Review is opened within the cycle.

Doctrinal Drift is not the same as Doctrinal Omission, which concerns what was never entered into the record, nor as Doctrinal Integration, which concerns the reconciliation of divergences once identified. The three are administered by separate offices that disagree about the order in which they should be applied. Readers are advised not to raise the question at a floor desk.

The Drift-Sheen Residue

Every doctrinal drift event leaves Drift-Sheen, a faint luminescent residue that settles on the bindings of the affected texts and, in severe cases, on the surrounding shelving. Drift-Sheen is also a residue of Retroactive Drift events, and the two residues are not distinguishable by sight. Wardens of the stacks are instructed to measure sheen depth with the standard gauge and to record the reading in the negative, in Standard Drift Units, before any attempt at interpretation. In practice the gauge is read, the reading is recorded, and the interpretation is attempted anyway.

The Whitethorn Review

The most-cited instance of Doctrinal Drift remains the Whitethorn Review of the winter of Year 1,096, on the floor catalogued as Floor 1,412. A recension of the Seventh Concordance was entered into the floor register with an alteration to Annex 3: the word "shall" had, over successive copying, become "may." The change was not marked. For eleven cycles every filing on the floor proceeded on the permissive reading, and every one of those filings was, under the original wording, void.

The drift was identified by Sub-Librarian Ellery Vance, who noticed that a routine notice of non-compliance had been filed by a steward who could not, under the "may" reading, have had standing to file it. Vance's report to the chamber runs to forty-one pages and is appended to the floor register, where it remains the longest entry. The review established two standing principles: first, that an alteration of a single modal verb constitutes a drift event of the first magnitude; and second, that no filing made under a drifted reading is voided retroactively, since to void them would compound the drift rather than correct it. The second principle is contested to this day.

"We are not asked to restore what the text said. We are asked to record what it has become, and to note the difference in the negative."

— Ellery Vance, Report to the Chamber of Measured Drift, Year 1,096

Instruments and Counterweight

The central instrument of record is the Doctrinal Variances Register, maintained by the chamber since Year 872 and closed to public inspection on grounds of length. Entries are made in the negative, in SDUs, and cross-referenced to any Lingual/Nominative Drift noted in the same text. Anti-Drift Measures are the recognized counterweight to Doctrinal Drift: periodic re-recitation of the Concordances in the presence of two witnesses, the use of fresh ink for all annexes, and the sealing of amended folios so that later hands cannot undo them without leaving a mark. The measures are considered effective; the chamber's own figures show drift declining by no more than one SDU per cycle.

Scholarly Disagreement

Whether Doctrinal Drift can occur without a corresponding drift in language is the oldest dispute in the field. The Second Concordance holds that doctrine is carried only in words, and that a doctrinal drift is therefore always preceded, and in strict terms caused, by Semantic Drift. The Fifth Concordance disagrees flatly, citing the Azurite Drift of Floor 88, in which the words were unchanged and the doctrine shifted all the same because the readers had changed. Attempts to settle the question by appeal to the Concordance of Precedents have failed since Year 903, when the relevant volumes were found to have drifted from one another.

In the ordinary conduct of the floors the dispute is moot. A γ-7 is filed, a Substantive Review is opened, the drift is measured in the negative and entered in the register, and the reading stands until it drifts again. A visiting reader who wishes to consult a drifted text should apply at the floor desk before the second bell; texts are not issued during the afternoon, when the sheen reading is taken.