Polchinski's Paradox
Updated 2026-08-05
INTRODUCTION
English translation pending.
CORE DEFINITION
Proposed by Joseph Polchinski as a challenge to time travel consistency, the scenario has a billiard ball enter a wormhole, emerge in the past, and collide with its earlier self, deflecting it so that it never enters the wormhole. The sequence is self-contradictory, which suggests that only self-consistent histories are physically permitted. The core claim is that consistency constraints exclude contradictory causal paths. The qualification is that the argument concerns classical trajectories in a hypothetical spacetime and does not settle whether closed timelike curves exist.
SCAFFOLDING EFFECT
Reduce cognitive load
- Use Contradiction Scan: In a feedback chain, check whether any path negates its own precondition. - Use Path Elimination: Treat a self-contradicting route as unreachable rather than as a live option. - Use Consistency Search: Look for the self-consistent solution instead of forcing the contradictory one.
Anchor fast decisions
A closed causal chain requires every event in it to be both cause and effect of the others, so any step that removes a precondition destroys the whole loop. Because the contradictory trajectory cannot be completed, the physically permitted solutions are those in which the past remains consistent with itself. The constraint therefore works by elimination, leaving only trajectories that reproduce the conditions they started from.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- en.wikipedia.orghttps://en.wikipedia.org/wiki/Joseph_Polchinskiverified
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