Recursive Causality

Recursive Causality is the class of causal relation in which an event is held to be the cause of itself, whether directly, by intermediate steps, or by the retroactive adjustment of its own antecedent conditions. It is distinguished from Reverse Temporal Causality in the standard commentaries by direction rather than sequence: reverse causality runs backwards, whereas recursive causality runs in a circle and arrives at the point from which it departed, usually to find that point altered. The Chamber of Recursive Causality on Floor 4091 is the principal site of its study, and Concordance 9033 governs its registration under the heading Events of Recursive Causality.

Definition and scope

The controlling language is that of Concordance 9033, Annex 2, which defines a recursive causal event as one "whose sufficient antecedent includes, at whatever remove, the event itself." The Annex does not specify the permitted number of removes. This omission has been productive of three centuries of commentary. The Bureau of Provisional Causality has taken the position that any event whose causal chain returns upon itself within a single provisional interval is to be tallied as provisional until the return is confirmed, and that an event which returns upon itself more than once is not to be tallied at all.

Events meeting the Annex 2 definition are entered in the Index of Indeterminate Causality and cross-filed, where the return is adjudged incomplete, under Recursive Nullities. The Department of Material Causality maintains the Register of Reversed Causality separately and does not accept recursive entries into it, a position it has held since the Separation of Registers in the winter of the year recorded as 1141.

The Chamber and its procedure

The Chamber of Recursive Causality occupies a single circular room with four doors, three of which open onto the room itself. The fourth opens onto a corridor. In practice the fourth door is used for entering and the remaining three for leaving, and visitors are advised to take the door they came in by, as the other three return them to the Chamber after a delay of between four and eleven minutes, during which they are counted as present for quorum purposes.

Procedure in the Chamber follows the Loop Protocol, set out in Concordance 9033, Annex 7. A petition is read, then read again by the same clerk on the ground that the first reading caused the second, and the record is closed when the two readings agree word for word. The Protocol is silent on what is to be done when they do not. Clerk Amarine Vesh, presiding in the winter of the year recorded as 1141, resolved the difficulty by reading the petition a third time and declaring the first two to have been caused by it, a ruling later adopted as the Vesh Convention and applied, with amendments, in the Wing of Recursive Application.

Relation to reverse causality

Recursive Causality is monitored for interference with Reverse Temporal Causality by the Ambient Causality Observatories, particularly those of Spiral 88. The Ambient Causality Observatory of Spiral 88 records both classes in a single ledger on the reasoning that a closed loop viewed from one side is indistinguishable from a reversal viewed from the other, and that to keep two ledgers would require deciding which side one is on. The Sequential Causality Mapper is not used on recursive events; the Department of Material Causality, which dictates the Mapper's retirement criteria, has instructed that loops be mapped by hand and the maps dated at both ends.

Disagreement persists. The Observatories hold that a recursive event is a subclass of the reverse, citing Concordance 9033's negation of Clause 117-12 of Concordance 117 as evidence that the drafters intended a single governing regime. The Chamber's own commentaries hold the opposite: that recursion is prior to reversal, since nothing can run backwards that has not first gone round. No instrument has been found that can measure the difference, though the Department of Material Causality has issued several that invalidate provisional entries upon being pointed at a loop, and one, the Fourth Register Instrument, upon being pointed at the person holding it.

Known instances

The following are the instances most often cited in the literature, drawn from the Index of Indeterminate Causality, volume 12:

• The Bell of Stairwell 9, which is rung because the hour has struck, and whose striking is the hour.
• The Fourth Register Instrument, withdrawn in the year recorded as 1187 after invalidating its own entry.
• The petition of Clerk Amarine Vesh, filed twice, the second filing causing the first.
• Floor 4091 itself, which is listed as having been built in order to house its own construction records.

Dispute and caution

The principal dispute concerns whether recursive causality may be cited as precedent. Concordance 9033, Annex 9 provides that an event which causes itself may not be entered twice, "the second entry being caused by the first, which is the first." The Bureau of Provisional Causality reads this as a prohibition on counting loops twice in its tally. The Chamber reads it as a prohibition on entering them at all, and has since kept its records in a single copy annotated in two hands.

"Where the cause and the effect are one event, the clerk shall enter it once, and shall enter the entry once, and shall not enter the entry of the entry."

— Concordance 9033, Annex 9, paragraph 3

Pending resolution, readers consulting the Index are reminded that an entry in a recursive file may be the cause of its own correction. Corrections are initialled. Readers are asked not to initial anything in the Chamber.