Subclause 9.2: Causal Imprint Analysis

Subclause 9.2: Causal Imprint Analysis is the operative provision of Directive 7-Δ governing the reading of residual causal marks left on objects, persons, and — in one contested class of cases — on rooms. It was inserted into the Directive in the winter of the year the Tower records as 4411 by amendment, replacing a single sentence of the original text that had proved unenforceable, and has been amended four times since without any of the amendments being consolidated into a clean recension. Clerks of the Causal Verification Bureau are expected to hold all five versions in mind simultaneously. Most do.

The Subclause defines a causal imprint as any persisting alteration in an object's causal profile attributable to a prior event, whether or not that event remains otherwise recoverable. It sets out three degrees of imprint — primary, residual, and vestigial — and assigns each a standard of proof. Primary imprints require an uninterrupted chain of custody. Residual imprints require corroboration by instrumentation. Vestigial imprints require only that the reader state, in writing, that they believe something occurred. This last provision was challenged twice and upheld twice, on the reasoning that a vestigial imprint is by definition too faint to be tested, and that a written belief is therefore the strongest evidence the class admits.

Relationship to the Causal Modelling Corpus

Subclause 9.2 is subordinate to the Principle of Causal Conservation, which forbids the creation or destruction of causal potential, and to the Retro-Causal Ripple Model wherever a reading discloses an event that appears to precede its own cause. Referral is mandatory in such cases; the Subclause does not permit a reader to resolve a reversed sequence locally. Such imprints fall instead under the quarantine provisions of Addendum 2004- and are removed to the West Wing of Floor 2004, where they are analysed and, if analysis fails, kept.

The Subclause is frequently confused with the adjacent discipline of Substance Analysis, which examines what an object is made of rather than what has happened to it. The distinction is enforced by the Directorate and enforced badly: a joint memorandum of 4416 records that of eighty-one objects submitted to the Bureau for imprint reading, thirty-four were found to be of unknown composition and could not be read at all, and eleven turned out to be portions of the same object.

The Floor 1188 Dispute

The Subclause's most cited application concerns the so-called reading of the counting-room on Floor 1188, in which a junior reader, Aurel Thask, reported a residual imprint indicating that a ledger had been removed from the room twice, in that order. The report was challenged by the room's custodian, who observed that the room had held no ledger. The Bureau upheld the reading on the ground that Subclause 9.2 asks what imprint an object bears and not what the object is, and that a room may bear the imprint of a ledger it never contained.

"The question before us is not whether the ledger existed. The imprint establishes that it did not, in a manner consistent with its having done so."

— Causal Verification Bureau, ruling of 12 Frost 4418, in re Floor 1188

Thask was subsequently transferred to the Office of Stairwell Verification, where he remained for nineteen years and declined two promotions. His grievance — that his own ruling had been misread as a joke by three separate chapters — is preserved in the Bureau's correspondence files and is, by word count, its longest.

Dispute over the Standard of Proof

Scholars disagree as to whether the three-degree scheme in Subclause 9.2 is original to the Subclause or imported from Specificity Analysis, which employs a similar tripartite ladder for the ranking of precedents. The amendment record is silent. The Guild of Primary Cataloguers maintains that the scheme is a borrowing and cites its own internal ordinance of 4390 as the true origin; the Causal Mechanics Chapter maintains the opposite and has twice declined to convene a joint committee on the question.

A second and livelier disagreement concerns the binding force of the fifth recension. The fourth recension of Subclause 9.2 was amended under Spiral 299, Subclause δ.4, which governs the use of Provisional Concordance Citations. The fifth was not. Clause 1 Provisional Architecture therefore treats the fifth as advisory, while the Bureau applies it as settled. The practical consequence is that a reading certified under the fifth recension is valid throughout the Tower and invalid on three floors, which the Bureau has described in correspondence as "a tolerable irregularity."

Certification and Marking

A completed Causal Imprint Analysis is certified on Form 9.2-C, countersigned by the reader and by a second officer not present at the reading. Completion requires the enumeration of all three degrees, whether or not all three were found; the entry "none observed" is permitted, but only once per form. Analyses touching on Expedited Verification Annex B7 Subclause Gamma are additionally marked with the Imprint of the Closed Fist, which is applied in red and must be allowed to dry before the form is folded. Pages folded early are returned unread.

Certifications relating to oneiric material are filed under Imprint 001-Sigma and are not handled by the Bureau. Materials entering the reading rooms are admitted through the Vestibule in accordance with the Third Concordance, Clause 11, Subclause 2; readers are asked not to carry liquids past the second landing.

Instruments and Known Defects

The Subclause prescribes no particular instrument, and in practice the Bureau's readers use the Type 4 resonating caliper, the Type 6, and, on the upper floors where the Type 6 will not seat, a weighted cord. The Type 6 has a known fault: under prolonged use it registers its own casing as a residual imprint of recent violence. The Bureau's standing instruction is to subtract this reading and to note the subtraction. On Floor 2004 the subtraction is not permitted, and the instrument must instead be warmed for one hour before use.

No imprints have been successfully read from the stairwells. The Office of Stairwell Verification regards this as a settled matter and does not accept submissions on it.