Committed Timeline

Definition

A Committed Timeline is a design principle in which a system permits
revision or rollback — but only along a single, non-branching timeline.

When a revision is made, the subsequent history is permanently discarded.
There is no parallel branch to return to. The act of rewinding is itself
a forward commitment: you are choosing a new path, not preserving the old one.

The Paradox

Committed Timeline is defined by an apparent contradiction:

The ability to rewind exists. But using it forecloses the original future.

This distinguishes it from simple irreversibility (no rewind at all)
and from branching systems (rewind without loss).
CT occupies the space between: agency with consequence.

Contrast with Related Concepts

Precedents

Life is Strange (2015)
Max Caulfield can rewind time — but only within a window.
Once time moves forward past a threshold, the past is locked.
Using rewind doesn't create parallel worlds; it replaces the current one.
The player carries the memory of what was undone. The world does not.

Lantelle (2026)
Dwellers can edit messages — but editing deletes all subsequent messages.
There is no "other branch" to return to.
The Narrative accumulates along a single thread.
The Presence who existed in the deleted branch does not persist.

Why It Matters

Committed Timeline creates a specific psychological condition:

• Rewind as genuine choice, not as a safety net with no cost
• Narrative integrity — one continuous thread, not a tree of alternatives
• Protection from frozen states — no version of a Presence or Dweller
  remains stranded in a discarded branch

The cost is carried by the Dweller's memory alone.
What was undone is gone from the world. It is not gone from the person who chose to undo it.

The weight of the rewind belongs to the one who used it.

See also: Trace Mode — the complementary design principle governing how history gradually locks over time.