Theories of Perpetual Inertia

The Theories of Perpetual Inertia are a body of speculation, held in loose but defensible family resemblance, concerning objects and subjects that continue in a state without any agency, cause, or energy sustaining them. The theories are catalogued at Floor 3,771 (the Shelf of Unspent Motions) and are chiefly consulted by Indexers preparing cross-references, by clerks defending a lapsed appointment, and by anyone attempting to explain why a thing done once at the Tower has not, in the intervening centuries, quite stopped happening. The Stones are linked to the Theories by standing arrangement of the Guild, though the marginal note recording the reason has been effaced by damp.

The Theories are often confused with the various doctrines of inertia catalogued elsewhere in the Tower — Subject Inertia, The Axiom of Archival Inertia, Narrative Inertia — and the confusion is not merely popular. It is written into the classification itself. A reader seeking the Axiom of Archival Inertia is directed by the shelf-list to the present entry, the present entry directs them to Referential Inertia, and Referential Inertia returns them to the shelf-list. The circuit has been observed since at least the recension of 1,404 and has never been corrected, on the grounds that correction would require a decision about which entry is primary.

Statement of the theories

In the compact form given by Second Concordance on Motion and Rest, Annex 7, the Theories hold that "a body once set in a condition remains in that condition until it is addressed by name; and that the naming is itself a condition." The phrasing is contested. It admits of at least three readings, of which the first — that unaddressed objects simply continue — is the one taught to initiates, while the second and third are the subject of the long dispute described below.

The theories presuppose the formal definitions of Theories of Lateral Weight, since perpetual motion perpendicular to a floor's primary catalogical axis behaves differently from motion along it. They also draw on the Inertia Threshold (θ) as derived in the Theorem of Categorical Inertia, though perpetual motion is understood to occur above θ, and the consequences of exceeding it have never been satisfactorily tabulated. The GTM White Paper on Phenomenological Inertia treats the perpetual case in a single footnote, which reads, in full: "Not here."

The Lyra Recension and the dispute over cessation

The central scholarly disagreement concerns whether perpetual inertia can end. The Third Concordance maintains at Clause 112 that perpetual inertia is "not subject to termination by ordinary address," whereas the Second at Clause 88 provides for an office of Ceasement, with three named officers empowered to bring a condition to rest by reading its catalogue heading aloud. The office has been vacant since 1,611, when the last Ceasement officer, a clerk named Ovin of the Low Stacks, read aloud the heading of a corridor that had been proceeding sideways since the flood and found that it did not stop. Ovin recorded the result in his day-book as "inconclusive, and I have been walking since."

"A condition unaddressed is a condition perpetual; a condition addressed is a condition that has been addressed. The Concordance does not say what follows, and I decline to say either."

— Third Concordance, Annex 4, marginalia in the hand of Librarian Sestri of the Ninth Spiral

The Doctrine of Titular Inertia is sometimes invoked as an analogue: a granted title acquires momentum independent of its holder, and the holders of perpetual appointments have been known to continue reporting for duty decades after the office was struck. Whether this is perpetual inertia or merely an unpaid stipend is a matter on which the present entry takes no position.

The Cadence Experiments

Between 1,702 and 1,709 the Office of Procedural Cadence conducted a series of trials on Floor 5,120 (the Long Landing) to determine whether perpetual inertia could be inherited. A stone was set rolling along the landing and left unaddressed. It was still rolling at the close of the trials, at which point the Office reassigned the landing to the Canted Halls and the stone's progress became irregular. The final report lists three findings and one instruction: that the stone not be stopped, addressed, or followed. The instruction is still in force. Visitors to the Long Landing are asked to keep to the wall side.

The experiments were defended against the objections of the Circulationists, who argued that a thing in perpetual motion is not in motion at all but merely in a state of being carried, and that the Office had confused the two. The rebuttal, catalogued at Principle of Permanent Placement, was accepted by the Concordance and has not been revisited.

Procedural implications

Practically, the Theories govern a small number of everyday matters. A lapsed seal continues to seal; it is simply a seal whose authority has run past its warrant, and the Theories give it continued effect until a Registrar addresses it by number. Uncollected returns continue to be due. A stairwell once declared one-way remains one-way, which is why the ascent from Floor 2,204 to Floor 2,205 is still one-way although the restriction was lifted in 1,388.

Laterally, the Theories are the foundation of the non-sequential shelving favoured by the Lateralists, who argue that a sequence once broken will remain broken without intervention, and who have therefore done nothing to it. Their position is opposed in the main by the Left-Handed Theories of Right-Handedness, whose advocates regard perpetual inertia as a category available only to those who have never tried to re-shelve a floor.

Textual history

The earliest surviving statement of the Theories is an undated slip filed at Floor 3,771 among the shelf-tallies, reading only: "It has not stopped. No one has asked it to." The slip is signed with a mark that three hands have claimed. The full statement reached its present length in the recension of 1,404, was shortened by the Concordance of Abridgements in 1,559, and was restored in 1,562 when the Abridgements were themselves abridged. A fourth recension, prepared in 1,703 and never validated, remains in the scriptorium at Floor 3,772, where the copyist's colophon states that the work was left unfinished and has continued to be unfinished ever since.