Fact 205

Fact 205 is the inscribed statement "the air in the Central Pneumatic Stacks is of constant temperature (19°C ±0.1)", held in the Archives of Incontestable Fact and widely cited as the shortest recorded interval between a holding's creation and its promotion to full Fact. Its elevation is taught in the scriptoria of the middle floors as the model case for the Fact Reaffirmed rite, though the case is almost always taught incorrectly.

Origin as a holding

The statement was first entered not as a fact but as a holding, in the ledger of the Determination on Inferred Holdings, on 3 Hespid, Year 41 of the Current Recension. It was inferred rather than observed: three successive expeditions into the Stacks had recorded thermometer readings of 18.97°C, 19.02°C and 19.00°C at staggered depths, and a junior clerk of the Curatorium of Verification named Halivate Renn observed that the readings fell within a tolerance narrow enough to be stated as an invariant rather than a series. Renn's covering note, still bound with the original slip, reads in full: "The observations are few. The tolerance is honest."

The holding was contested almost at once. A Notice of Incongruent Fact was filed against it in the same quarter, not on evidentiary grounds but on the grounds that a holding concerning a place no one had fully traversed should not be stated in the definite article. The challenge failed; the article stood.

Elevation and the Fact Reaffirmed question

The elevation of Fact 205 to the Archives is usually attributed to a Fact Reaffirmed rite performed by the Custodians of Pure Fact under the authority of Concordance VII, Annex δ. This is the account given in the standard instructional recension used on floors 300–311, and it is wrong in one particular that the Judiciary of Cross-Reference has twice declined to correct.

The instrument actually applied was Fact Amended, not Reaffirmed. The original holding had specified 19°C ±0.2. The tightening to ±0.1 followed a fourth expedition, in the winter of Year 42, which returned three readings within 0.04°C of one another and one reading of 21.4°C. The anomalous reading was recorded, appended, and never explained. The amendment narrowed the tolerance around the three concordant readings and left the fourth in an annex, where it remains.

"The annex is part of the Fact. It is not part of the stated interval. These are different things and clerks would do well to keep them apart."

— Fact Amended instrument 205/4, marginal note in the hand of the presiding Custodian

The Central Pneumatic Stacks

The Stacks occupy the interior shafts between floors 188 and 206, a region of vertical ducting through which the Tower's air is drawn, warmed and returned. Access is by ladder from a single hatch on floor 203. The temperature is maintained by a system of brass registers whose control mechanism has not been inspected in living memory; the registers are adjusted by hand, twice daily, by whoever is assigned to the hatch. The assignment is unpopular and rotates by lot.

Fact 205's defenders note that the constancy it records is not spontaneous but maintained, and that a maintained constant is a fact about the maintainers as much as about the air. The formulation has never been revised to say so.

Scholarly disagreement

There are two live disputes concerning Fact 205. The first is whether its elevation should be reclassified in the instructional recensions from Reaffirmed to Amended. The Custodians of Pure Fact maintain that the distinction is procedural and immaterial; the Curatorium of Verification maintains, in a memorandum of Year 63 that has never been answered, that teaching the wrong rite "produces clerks who file the right document for the wrong reason, which is the beginning of the Impossible Fact."

The second dispute concerns the anomalous 21.4°C reading. A minority position, advanced by the archivist Sennet Vole and never formally filed, holds that the reading was correct and that the air in the Stacks is constant at 19°C except when the floor 203 hatch is open, at which point the Stacks are no longer the Stacks but a threshold. Under this reading Fact 205 is true and the annex is a boundary condition. Vole's position has not been put to the Custodians, on the ground that putting it to them would require deciding which of them it concerns.

Practical notes

Visitors to floor 203 are asked not to prop the hatch. Fact 205 is cited in the Tower's Discrepancy Reports as the standard against which instrument error is measured; a thermometer reading outside 19°C ±0.1 anywhere in the Tower is presumed faulty until proven otherwise, a presumption that has been overturned eleven times and reinstated twelve.