time travel
Enable an agent to recognise a time-travel claim or scenario, distinguish its intended meaning and evidential status, and determine which inferences or actions its temporal rules support.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
recalled by Codex without web access - no source was read
Researched by: Codex
Purpose and description
Enable an agent to recognise a time-travel claim or scenario, distinguish its intended meaning and evidential status, and determine which inferences or actions its temporal rules support.
Time travel is the physical or hypothetical passage of a person or system to a future or past time, involving either unequal elapsed time along different trajectories or, more controversially, arrival in one's own causal past.
It can be Classify a proposed instance under an explicitly selected definition of time travel.; Compare traveller and external elapsed times using declared reference conventions.; Trace causal dependencies and expose contradictions or missing temporal rules.; Separate a mechanism's assumptions from the evidence supporting each claim about it.; Evaluate whether a proposed intervention or return journey is permitted within a scenario.; Identify observations that could distinguish a physical transfer claim from prediction, reconstruction or deception..
Distinguishing features
An instance must identify departure and arrival events and explain why their temporal relationship exceeds ordinary passage under the selected definition.
A claim must distinguish elapsed time experienced by the traveller from elapsed time assigned by the relevant external reference; subjective duration alone does not establish temporal travel.
Access to a depiction or prediction of another time is distinct from a traveller or signal actually reaching that time.
An arrival in an alternative history must be distinguished from arrival in the traveller's own past.
Internal consistency of a scenario and evidence that its mechanism is physically real require separate judgements.
Scope
+ Definitions that distinguish time travel from ordinary temporal passage
+ Travellers, departure and arrival events, reference frames and elapsed times
+ Forward, backward and branching-history travel scenarios
+ Mechanism assumptions, feasibility claims and evidence status
+ Consistency constraints, interventions and information transfer across time
+ Explicit temporal rules governing fictional and hypothetical instances
- General theories of time except where needed to interpret a travel claim
- Complete models of proposed time machines or their components
- Memory, prediction and historical reconstruction without temporal transfer
- Sleep, preservation and altered time perception considered independently
- Literary works and genres beyond their time-travel rules
- General multiverse theories without a specified temporal displacement
Characteristics
- Interpretive setting
- physical claim | philosophical scenario | fictional rule system | mixed | unspecified Determines what constitutes support and whether proposed operations are conceptual, narrative or physical.
- Adopted definition
- definition linked to its proponent, source and inclusion criteria Prevents one disputed meaning of time travel from silently governing every instance.
- Temporal direction
- future-directed | past-directed | bidirectional | reference-dependent | unresolved Separates claims with different causal commitments.
- Transferred entity
- person | other material system | signal or information | stipulated consciousness transfer | unspecified Makes explicit what allegedly travels and whether it meets the adopted definition.
- Traveller elapsed time
- seconds, with clock, path and uncertainty specified; undefined where no traveller clock applies Allows elapsed time along a traveller's path to be distinguished from external dating.
- External temporal displacement
- signed seconds or dated event interval under a named reference and comparison convention Makes statements such as arriving earlier or skipping centuries interpretable.
- History relationship
- single fixed history | revisable history | branching histories | unspecified Determines how interventions relate to the departure history.
- Mechanism support
- unassessed | stipulated | formally analysed | indirectly supported | directly tested | disputed | contradicted under stated conditions Separates assumptions, mathematical results and empirical support at the level of individual claims.
- Return accessibility
- return to departure history permitted | return only to another history | one-way | unknown Prevents arrival capability from being mistaken for round-trip capability.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 16 findings · 28 questions.
Definitions and instance boundaries Identify which meaning of time travel is being used and what must occur for an instance to qualify.
The registry has no definition, and different meanings admit different examples.
Competing inclusion criteria
Record definitions, their proponents and the disagreements that change classification.
Definition-dependent membership
Treat inclusion of differential ageing, past-directed arrival and other proposed cases as a question governed by an attributed definition.
- Which source or proponent supplies the definition, and what necessary conditions does it impose? provenance
- Does this definition include unequal elapsed times between travellers and observers, require arrival in the past, or use another criterion? definition
Travel versus temporal access
Separate transfer between temporal locations from experiences or representations of another time.
What crosses the temporal boundary
Specify the entity claimed to travel and distinguish its transfer from ordinary persistence, simulated experience or knowledge acquisition.
- What person, object, signal or other entity is claimed to connect departure and arrival? definition
- What distinguishes this case from waiting, preservation, remembering, predicting or viewing a reconstruction under the adopted definition? boundary
Temporal route and traveller Describe the departure, arrival, elapsed times and continuity of the proposed traveller.
Temporal displacement cannot be assessed without specifying what is compared and what persists through the journey.
Departure, arrival and clocks
Locate endpoints and define the clock or dating conventions used to compare them.
Reference-explicit displacement
Keep traveller duration, external elapsed time and temporal ordering separate rather than reducing travel to an unexplained date difference.
- Where and when are departure and arrival, and which frame, clock or event-ordering convention relates them? measurement
- How much time elapses for the traveller and the comparison observer, and how are those intervals established? measurement
Continuity and coexisting versions
Track the traveller's identity and path when different ages or copies may coexist.
Traveller continuity criteria
Record whether arrival preserves the original entity, produces a copy or transfers only selected information, without assuming these are equivalent.
- What criterion identifies the arrival entity as the departure traveller rather than a replica or reconstruction? definition
- Can multiple versions coexist, and how are their ages, memories and paths distinguished? boundary
Mechanisms and evidence Separate proposed mechanisms, their prerequisites and the evidence supporting them.
A coherent description, a formal possibility and a demonstrated capability warrant different conclusions.
Mechanism and required conditions
Expose the physical assumptions or fictional stipulations that make the route available.
Conditional travel capability
Represent a proposed route as conditional on specified conditions rather than treating a named mechanism as proof of feasibility.
- What mechanism is proposed, and which assumptions or stipulated rules permit the temporal route? definition
- Which required conditions are established, hypothetical, unavailable or left unspecified in the supporting material? provenance
Claim-specific verification
Assess evidence for precisely stated temporal effects and identify discriminating observations.
Support does not transfer automatically
Evaluate each claimed capability separately, including whether evidence for a clock difference supports the stronger travel claim being made.
- What exact capability does each source analyse or test, and under what conditions? provenance
- What observation would distinguish the claimed transfer from clock error, ordinary communication, prediction or fabricated records? measurement
- What additional evidence is required before an agent may describe this capability as demonstrated? action
Histories and causal consistency Make explicit how arrival and intervention relate to earlier events and alternative histories.
The consequences of travel depend on the scenario's history rules, especially when actions affect the conditions of departure.
History identity and revision
Distinguish participation in one history, revision of a history and entry into another branch.
Destination history relationship
Specify whether the destination belongs to the departure history and what, if anything, an intervention changes.
- Does arrival occur in the departure history, a revised history or a separate branch? definition
- If an earlier event is altered, what happens to the departure event, the traveller's memories and records of the original outcome? boundary
Causal loops and conflicts
Trace dependence across temporal routes, including self-undermining actions and circular provenance.
Consistency obligations
Identify contradictions and loops in the stated rules without presuming that a causal loop is itself a contradiction.
- Can an allowed action prevent the departure or mechanism on which that action depends, and how do the rules address this? boundary
- Does an object or piece of information circulate through a causal loop, and is any origin outside that loop specified? provenance
- Which interventions must be rejected or left unresolved to preserve the scenario's stated consistency rules? action
Reachability and intervention Determine which destinations, interactions and return routes a specified scenario permits.
The ability to reach another time does not by itself establish destination control, influence or return capability.
Destination and return constraints
Describe the accessible temporal range, spatial targeting and conditions for a return journey.
Reachable event set
Bound permitted journeys using the mechanism or scenario's actual restrictions.
- Which dates and locations are reachable, with what precision and any limit tied to the mechanism's creation or operation? measurement
- What permits a return, and does return mean reaching the original history, location and intended date? action
Interaction and transfer limits
Specify what can be observed, changed or carried across the route.
Permitted temporal operations
Distinguish observation, communication, material transport and intervention, with their separate constraints.
- Does the route permit observation only, message exchange, material transfer or changes to destination events? boundary
- What may an agent infer or attempt from the supported capabilities, and which operations require additional assumptions? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- This entry covers the physical and philosophical concept, including its fictional use; the registry supplies no narrower sense.
- Relativistic differential ageing is experimentally established; describing it as time travel is partly terminological.
- Backward time travel has not been demonstrated; mathematical permissibility, physical realizability and proposed chronology-protection mechanisms must be distinguished.
- Which of these check these first hold for the sense of time travel this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Future-directed travel through relativistic time dilation
- Past-directed travel along closed timelike curves
- Hypothetical travel through a traversable wormhole with a time offset
- Which of these kinds and varieties hold for the sense of time travel this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Relativistic clock comparisons experimentally establish unequal elapsed time, the physical basis of future-directed time travel.
- General relativity research examines spacetime geometries that permit closed timelike curves.
- Philosophy uses time-travel scenarios to examine causation, identity and logical consistency.
- Fiction uses time travel to explore alternative histories and consequences of changing the past.
- Which of these real-world use hold for the sense of time travel this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Proper time elapsed along a traveller's trajectory - Depends on the trajectory and spacetime geometry; no general typical range - second
- Difference between elapsed times recorded by reunited clocks - Depends on relative motion and gravitational conditions; no general typical range - second
- Which of these typical measurements hold for the sense of time travel this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Treating mathematical solutions that permit backward time travel as evidence that such travel can be physically achieved.
- Past-directed travel raises consistency problems, including scenarios in which an event prevents its own cause.
- Causal loops can leave information or objects without an ordinary external origin, creating explanatory puzzles.
- Proposed wormhole time machines depend on unverified assumptions about traversability, stability and allowable matter.
- Confusing experimentally established time dilation with demonstrated travel into the past.
- Which of these failure modes and hazards hold for the sense of time travel this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Time dilation - Time dilation is unequal elapsed time between clocks following different trajectories; it does not itself imply access to the past.
- Closed timelike curve - A closed timelike curve is a specific geometric path returning to the same spacetime event; time travel is the broader concept.
- Wormhole - A wormhole connects spacetime regions in a proposed geometry; it need not be traversable or permit time travel.
- Suspended animation - Suspended animation reduces biological activity while external time passes, without requiring relativistic clock differences or backward travel.
- Retrocausality - Retrocausality concerns influence from later events on earlier ones and need not involve a traveller moving into the past.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of time travel this model covers, and on what evidence? provenance
What the second pass must settle
- Which reference works and proponents supply the principal competing definitions, particularly concerning differential ageing and ordinary persistence into the future?
- Does an existing Vercy world model already own this concept, requiring this registry entry to link to it?
- Which proposed mechanisms have credible formal or empirical support for each specific capability, and which prerequisites remain unresolved?
- Should information-only or consciousness-transfer cases qualify as time travel under this entry, or remain related boundary cases?
- How should branching-history arrival be classified when the destination resembles the traveller's past but is not part of the departure history?