Stack of Ephemeral Certainties

The Stack of Ephemeral Certainties is a prepared neutral repository of Predictive Certainties, presently maintained on Floor 404 under the joint superintendence of the Directorate of Predictive Annotation and the Bureau of Ephemeral Holdings. It is, by the Bureau's own count of 11 Felbrig 98, the fourth-largest continuous stack in the Tower and the only one whose contents are understood to be provisional in every particular. Nothing is added to the Stack without an accompanying statement of how long the addition is expected to remain true; nothing is removed except by a finding that it has stopped being so.

Composition

The Stack is composed primarily of Grade Alpha Predictive Certainties, as recorded in the catalogue entry above, though Grades Beta through Delta are present in the lower twelve register-feet where earlier deposits have settled. The Grades are assigned by the School of Predictive Curation on the basis of the finalized Assessment of Predictive Mass; a certainty whose Assessment has not been finalized is held in the antechamber on Floor 403 and is not, strictly speaking, part of the Stack, though visitors frequently believe otherwise and the guards have stopped correcting them.

Materially, the Stack is not uniform. Grade Alpha Certainties take the form of thin bonded leaves, typically eleven by seventeen inches, pressed and stored flat. Grade Delta Certainties are stored rolled, a practice introduced after the Ordinance on Ephemeral Inks of 71 Felbrig 12, which forbade the flat storage of any document whose ink is rated below Clarity Six on the ground that the weight of the sheets above progressively transfers the text into the sheet below, until a stack of forty distinct certainties reads as a single very confident one.

Relocation from Floor 317

The Stack stood on Floor 317 for an unrecorded period, plausibly since the floor's original designation under the Seventh Concordance, Clause 22. It was moved to Floor 404 during the Provisional Stack Relocation campaign, an undertaking of the Office of Ephemeral Cartography that consumed nine hundred and four porter-hours and was twice suspended for want of a cart small enough for the eastern stairhead. Floor 404 had been reinforced as a logical plinth some decades earlier and was certified fit to bear the Stack's bibliostatic pressure, which the Ephemeral Gradients placed at 14.2 hessians at the point of maximum load.

"No stack shall be relocated to a floor whose plinth has not been certified, nor to any floor on which a stack of contrary disposition is already held, nor on a Wednesday."

— Third Concordance, Annex 9-C

The Wednesday clause has never been satisfactorily explained. The Warden of Boundary Arbitration has ruled twice that it is directory rather than mandatory, and twice been overruled by the Warden of Ephemeral Stacks, who holds that a Concordance does not write words for decoration.

The Cartography of Ephemeral Stacks

The Stack is the principal reference case in the Cartography of Ephemeral Stacks. Its pressure profile is published in every revised edition of that survey and is the standard against which new stacks are measured; a stack whose profile falls within nine-tenths of the reference is said to be held to certain form, and one that exceeds it is quarantined under the Doctrine of Predictive Quarantine. The survey's current edition (rev. 103) describes the Stack as "the most thoroughly measured object in the Tower, and the least settled."

Measurement is not without hazard. During the winter of 96 a survey party of the Office of Ephemeral Affairs attempted to take a full aperture reading of the Stack's southern face and returned with a reading that described a stack nineteen feet taller than the room containing it. The discrepancy was referred to the Fourth Librarian of Ephemeral Geometry, who determined that the party had measured the reflection in the plinth's polished coping and not the Stack itself, and who declined to rule on which of the two was the truer object. The finding is still cited in disputes over Ephemeral Audits.

Disputed Status as Ephemeral

The principal scholarly contention concerns whether the Stack remains ephemeral at all at its present size. The West Stack Brief of 101 argues that a certainty which has survived four relocations, two audits, and a partial inundation has acquired a de facto permanence that no Assessment of Predictive Mass may ignore. Against this, the Department of Predictive Cataloguing maintains that ephemerality is a property of a certainty's content and not of its tenure, and that the West Stack Brief confuses how long a thing is kept with how long it is true.

The dispute has produced a small literature and one resignation. Clerk Ambrin Hask, who had kept the Floor 404 register for eleven years, withdrew from the order in 102 after being instructed to record the same certainty twice under two different Grades pending resolution. Hask's letter of withdrawal, preserved in the Bureau's miscellaneous file, states that the Stack had been asked to be two things at once and that Hask declined to be one of them.

Access

The Stack is not open to general consultation. Readers holding a Provisional Reader's Warrant may view the register ledgers on Floor 404 but may not touch the Stack, may not lean on the Stack, and may not read aloud within the rail. Requests to consult a specific certainty proceed through the Directorate and take, in practice, between four months and never.