Quantum Time-Lock

Quantum Time-Locks are a type of "universal" event implicated in the culling and management of Adjacent Worlds (並行世界). Within the Thaumaturgical community of the modern world, they are also referred to as Human Order Foundations (人理定礎).  The imposition of Quantum Time-Locks is one of the functions performed by the World.

Overview
A Quantum Time-Lock is a "universal" event iterated at regular intervals within a domain for the purpose of anchoring "the average expression of phenomena and occurrences" as immutable absolutes within a confirmed History.

In the Prologue of the Altera Route in Fate/Extella, it is stated that the intervals between Time-Locks are a century in scale, but Fate/Extella Material indicates that two Time-Locks in fact manifested between the beginning of the game and the ending of True Nero Route -- separated by a bit more than a month in time.

Though the "Universe" (宇宙) permits the birth of unlimited possibilities, countless Adjacent Worlds, and divergent developments of history, as the unrestricted propagation of this process would quickly exhaust the Universe's lifespan, those extraneous removed of the category of "timelines characterized by strength and stability" are periodically culled (伐採) by the World so as to prevent the needless expenditure of energy. The facilitation of this process is referred to as the Conservation of Phenomena (事象保存), effected by way of a heuristic audits (集計) of cumulative timeline survivability -- judging the persistence of a timeline's across the subsequent century.

The Moon Cell Automaton has concluded that the means by which the Human "Universe of Awareness" (認識宇宙) -- fundamentally unstable by nature -- is stabilized across Past, Present, and Future lies in the execution of "culling" and the formation of "records" (記録帯).

If left alone, the Great Tree Known as Time (時間という大樹) will branch without restriction, and the behavior of culling serves to remove those divergences that are unnecessary, leaving only the "trunk" to advance. This is the simplest image by which to comprehend the phenomena. Worlds that lie within the "trunk" are said to be "comparable" (他と同じ世界) of "Foundation" (世界の基盤); the human civilizations extant within them largely resemble one another in expression and format.

As worlds that advance too far into ruin or prosperity can only tend toward immutable outcomes, they are considered to be bankrupt of, and therefore culled ; consequently, that which is preserved and anchored as absolutes by the manifestation of Time-Locks are described to be "the Average Expression (平均値) of phenomena and occurrences" -- both because the contents of preserved realities tend to be "commonplace" amongst Adjacent Worlds, and because their outcomes on average aren't biased toward positive or negative valence.

Fate/Extella states that the energy required to account for the ceaseless proliferation of unnecessary worlds exists nowhere within this "Dimension" (次元), and that the Dimension itself may eventually exceed capacity if propagation persists unchecked. Furthermore, absent of culling processes, the Earth can persist at its present level of civilization for only another century before the Solar System dissolves beneath the sheer volume of the data produced by humankind. With culling processes safely in place, however, it's likely that the status quo can be sustained for another hundred million years.

The purview of events to be registered to record in an upcoming Quantum Time-Lock may be dictated only those who live within the era. Intervention from the past or future is incapable of directly influencing the formation of a Time-Lock. In Fate/Extella, the factor that determines the purview of a Time-Lock is referred to as "Observation" (観測).

Interference Correction
Any history that has been secured as a Time-Lock (固定帯) become as an existence impervious to interference from the past and future; events or phenomena that exist within the purview of the anchoring band are utterly immovable. Hypothetically, if one were to move to a chronological position in the past of an "anchoring band" to the end of modifying history, as time progresses unto the Time-Lock, history would be forcibly corrected (強引に復元) to its state of record.

In those universes wherein Quantum Time-Locks are imposed, the "outcomes" that have been registered to anchoring bands are categorically unchangeable. Thus, that which would be open for time travelers to modify would be invariably restricted to "process."

For example, let us presume that the "outcome" that "Britain was destroyed" is secured as a matter of record. In the circumstance that a process wherein "Britain comes to prosper; its wars are concluded; and happiness is granted to its people" is successfully brought about, in the moment that history advances unto the anchoring band, the outcome whereby "even so, Britain came unto its destruction" manifests.

One or two -- or any number of lives might be saved. However, modification to the overall course of the History of Man (人類史) is decisively beyond possibility.

To rephrase, it is potentially possible that by some immense undertaking, the course of the History of Man could be fundamentally denied by the successful revocation (破壊) of a "Quantum Time-Lock" -- but even by this method, that which is denied is restricted to "the History of Man that falls subsequent to the anchoring band."

Terminology
In the Avant Title of the Fate/Grand Order - Accel Zero Order event, Lord El-Melloi II makes references to certain terminology pertaining to the cosmology of Adjacent Worlds and Quantum Time-Locks, available to his comprehension as a consequence of temporarily becoming one with a Heroic Spirit.   It is unclear if these terms are in general parlance within the Thaumaturgical community.

In Fate/Extella Material, Items Permissible to Revision (編纂事象) and Items Designated for Removal (剪定事象) are collectively referred to as concepts implicated in the Operation of Adjacent Worlds (並行世界の運営概念). However, their relationship with the 2nd Magic (第二魔法) is unclear.

Adjacent Worlds

 * Adjacent Worlds (並行世界) refer to divergent timelines that advance in adjacence to one another. In Fate/Extella, it is stated that a World qualifies for culling if it entirely lacks the potential to diverge into Adjacent Worlds. Incidentally, Archimedes' capacity to travel between Adjacent Worlds is referred to as Sliding.


 * "Adjacent Worlds" are terminologically distinct within the canon from Parallel Worlds, which instead refer to timelines that advance in perfect parallel with no relationship of divergence.

Primary Branch

 * The Primary Branch (大幹) refers to the cluster of Adjacent Worlds (並行世界群) that form the Great Tree Known as Time (時間という大樹) -- comprising of the confirmed (確定) pathways of the History of Man; that which remains as of the completion of culling (伐採) processes. The worlds of Fate/Zero and Fate/Grand Order are stated by Romani Archaman to "lie near the center" of this cluster -- amongst many that closely approaching one another in their historical course. Worlds within the Primary Branch are said to exist along their "proper axis" (正しい軸), representing "the Average Expression (平均値) of phenomena and occurrences" across the timelines of humanity.

Items Permissible to Revision

 * Items Permissible to Revision (編纂事象) is a category name applied to the set of worlds within the Primary Branch. Refers to timelines wherein, outside of the Outcomes (結果) confirmed by a Quantum Time-Lock, the Processes (過程) leading up to an outcome may still be modified by time travelers. Beyond the circumstance that an "immense undertaking" overturns a Quantum Time-Lock, however, confirmed Outcomes within these timelines are immutable, regardless of interference from the past or future. Prior to the manifestation of a Quantum Time-Lock, all open and unculled timelines fall under this category.

Items Designated for Removal

 * Items Designated for Removal (剪定事象) is a category name applied to divergent timelines that have come to exist as realities entirely distinct from others (完全に別世界になり) -- that is to say, Otherworlds (異世界) wherein the "Foundation" (世界の基盤) is sufficiently deviant that its civilization no longer resembles those within the timelines of the Primary Branch. As the name implies, these realities are designated for culling.


 * In Fate/Extella, a set of overlapping criteria is outlined for the culling of Items Designated for Removal as of the manifestation of a Quantum Time-Lock :


 * The choices of a timeline's inhabitants can no longer effectively impact its future; possibilities no longer exist.
 * The past of a timeline can no longer be undone.
 * Continuous advancement unto ruin or prosperity has occurred, to the extent that the World has been bankrupted of, and its future has been consequently rendered immutable -- inevitably approaching utopia or destruction without deviation.
 * As of a hueristic audit of cumulative survivability prior to the fall of a Quantum Time-Lock, a given World fails to meet the qualifications to ensure "the operation of the subsequent era" (次の時代の運営) within a century's time.

"Universe"

 * Refers to a domain that encompasses space and time. In the world of Fate/Extella, two varieties of existence are referred to as "Universe" :


 * "Universe of Observation" (観測宇宙) refers to a domain of reality wherein the Concept of Time (時間の概念) is expressed as "Time Within Conscious Recognition" (認識される時間); also referred to as "Universe of Awareness" (認識宇宙). Per the circumstances of human consciousness, the events of the Past, Present, and Future cannot in this expression of time be distinguished as categorically discrete, as the Future continuously passes unto the Present, and the Present into the Past. In exchange for an incapacity to perceive that which lies beyond the Present, one whose awareness is attuned to the "Universe of Observation" obtains the capacity to alter the Present referred to as Tomorrow.


 * "Universe of Record" (記録宇宙) refers to a domain of reality wherein the Concept of Time is expressed as "Time Submitted to Record" (記録される時間) -- such that the Past, Present, and Future can be distinguished as categorically discrete entities per a chronological record of proceedings. The timelines represented within the Adjacent World Simulator (並行世界シミュレーター) of the Moon Cell Automaton may be collectively considered a "Universe of Record."


 * Per Fate/Extella Material, the "Universe" discussed within the context of Quantum Time-Locks refers to the "Universe of Awareness." It is however unclear if this phrase is synonymous to the term "Dimension" (次元) referenced in Fate/Extella; or how indeed the "capacity" or "energy limitations" inherent to the "Universe" restricts the propagation of timelines.

Fate/Prototype: Fragments of Blue and Silver

 * In the case that Manaka Sajyou succeeds in fulfilling Saber's wish of an eternal Britain, the Human Order Foundation collapses and the modern world is destroyed.

Fate/Grand Order

 * By way of the establishment of Singularities (特異点), Goetia overturns seven of the most significant Quantum Time-Locks within the History of Man so as to facilitate his plan, and to incapacitate any countermeasures effected against his actions by the Common Sense of Man (人理).


 * In the context of Fate/Grand Order as a whole, Quantum Time-Locks are referred to as Human Order Foundations (人理定礎) as they form the premises upon which the rationality of humanity necessarily operates. In their absence, the History of Man is itself reduced to chaos of arbitrary possibilities.

Fate/Extella

 * In Fate/Extella, the objective of Archimedes was to manufacture an Outcome whereby "Moon Cell is Destroyed" prior to the manifestation of the coming Quantum Time-Lock -- establishing a reality premised upon this condition.


 * Whereas originally, such a development could not occur, Archimedes repeatedly shifted between realities to the end of achieving his goal. From Archimedes' perspective, so long as the operation of Moon Cell could be entirely brought to a halt prior to the fall of the subsequent Quantum Time-Lock, victory would be his.


 * However, even if there were outcomes in which Archimedes was victorious, a route in which the complete termination of Moon Cell's processes occurred could not be reached. In the meantime, the Protagonist was able to confirm "an average world that bears the potential greatest" -- establishing the purview of the coming Quantum Time-Lock. Archimedes' machinations were consequently brought to ruin.


 * Incidentally, Quantum Time-Lock A manifested as of the start of the primary story-arc in Extella, when "the Protagonist enters the Stone Chamber of the Titan with Archimedes, and is split into parts"; Quantum Time-Lock B manifested as of the Ending of the True Nero Route.


 * Regardless of the actions taken by Archimedes between these two points in time, the "Outcome" was already decided.