Conceptual Inertia

Conceptual Inertia is the resistance a concept offers to revision once it has been validly shelved. It is the first of the three required attributes of any Conceptual Locus, preceding Metric Susceptibility and Recursive Stability, and the attribute against which all other measures in the archive are ultimately normalised. A concept with high Conceptual Inertia, in the phrasing of Second Concordance, Annex 6, "shall be presumed to mean what it has meant, until such time as it is amended in the presence of two Librarians and a witness."

The unit is the lod, being the inertia of the standard reference concept chair as shelved at Floor 4411 on 3 Ember 11. The lod is maintained as a physical artefact in a sealed case and is not to be handled. The case is opened on the first working day of each quarter so that the lod can be confirmed to be present. It has not been weighed since 11 Ember 4402, when the weighing was found to introduce variation.

Measurement

Conceptual Inertia is not measured directly. It is inferred from the effort required to move a concept from its assigned shelf, which is why every reading in the The Registry of Resonant Inertia is accompanied by the name of the shelving clerk and the number of the trolley used. Clerks who report anomalously low readings are asked to repeat the work on a different stair. Clerks who report anomalously high readings are asked to repeat the work on the same stair, so that the anomaly may be confirmed.

The primary instrument is the Torsion Frame of Floor 2210, a brass assembly on which a candidate concept is suspended between two opposed definitions and twisted until one of them yields. The Frame has four settings. The fourth setting is not used, and the handle has been removed.

Readings are expressed on the Inertia Threshold (θ) scale, adopted wholesale from the Theorem of Categorical Inertia, which holds that inertia rises with the number of subordinate categories a concept will tolerate before it begins to exclude them. The Theorem's derivation is disputed; see below.

Relation to other inertias

Conceptual Inertia is the parent quantity of the archive's several derived inertias. Subject Inertia is its value as fixed by the subject heading rather than the text; Referential Inertia is its value as carried by citations, which the Spoon Arbitration established may outlast the concept cited. Archival Inertia is the aggregate of the two across a whole press, and the critical factor in every procedure governed by the Theorem of Categorical Inertia. Narrative Inertia is a special case, applying where a concept resists revision because it has been told in a particular order.

The relation to Juridical Inertia is governed by the Inertia Clause, which fixes the exchange rate between a concept's resistance to redefinition and a precedent's resistance to being overturned. The Doctrine of Jurisdictional Inertia was separated from that body of practice at Chamber Docket 701-44C §22 and no longer contributes to this article's subject.

The Glynd Case

In the winter of the Year of the Lapsed Standard, the clerk Anselm Glynd was assigned to revise the shelving of the concept threshold, which had accumulated eleven subordinate categories over four centuries. Glynd found that each time he removed a category, the remaining categories grew heavier, and by the ninth removal the concept would no longer sit flat on the trolley.

Glynd filed a report proposing that Conceptual Inertia be treated as conserved rather than diminished, and that revision therefore relocate inertia rather than remove it. The report was well received. Glynd was transferred to Floor 11,000 and One to pursue the question, and the transfer was never rescinded. He is recorded as having sent three further memoranda and a request for a chair. The chair was not sent, on the grounds that the concept chair was the standard reference and could not be released.

"The concept will not be lightened. It may only be carried."

— Anselm Glynd, memorandum to the Shelving Office, 14 Frost 4403

Disagreement between the Concordances

The Second Concordance treats Conceptual Inertia as intrinsic: a concept is heavy because of what it is. The Fifth Concordance, Annex 2, treats it as relational: a concept is heavy because of what has been shelved beside it, and would be light elsewhere. The two positions are irreconcilable, and the Librarians have declined to settle the question, noting in Concordance Minute 88-C that "a concept moved to a different shelf and found to be lighter has not thereby been proven relational, only lucky."

The practical consequences are not trivial. Under the Second Concordance, a revision of a concept's definition must be preceded by a survey of the whole floor. Under the Fifth, a clerk may simply move the concept and re-measure. The Guild of Clockwork Purists intervened in 4409 to object that the Fifth Concordance's position made inertia a function of furniture, and that a cabinet once moved had been found to alter the weight of six adjacent concepts and a staircase. The Guild's memorial was accepted and filed under Stairs.

Absorption of excess

Inertia generated by the cataloguing process does not accumulate indefinitely on the shelf. Excess is drawn off through the Primary Inertial Buffer, the foundational system that absorbs, dampens and redistributes it across the stack. The Buffer has no known capacity and is inspected annually through an aperture on Floor 3,000 which admits light and nothing else.

The Cataloguing Directives for Ephemera rely on this arrangement. Ephemera are defined therein as "factual lacunae endowed with sufficient conceptual inertia to merit provisional shelving," and it is Conceptual Inertia that qualifies a lacuna for shelving at all, while the Buffer ensures it does not qualify for very long. Entries which exceed the Buffer's tolerance are reclassified as Chronic Discrepancy Inertia and moved to the north face, where they are shelved face-in and not read.

Practical notes

Trolleys are to be pushed, not pulled. Concepts in excess of 40 lod require a second clerk, and concepts in excess of 90 lod require a Certified Tension Clerk, of whom four are currently practising.