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    LoyalLoyalJusticeJustice
    Made withinDC&Austin
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    Home/Original/inverse
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    Inverse View

    It is not the case that The requirement that causal curves with a future endpoint in the time travel region and no past endpoint must intersect Σ₀ is too strong, because it rules out Thornian time machines altogether.

    ?Set your confidence on the premises below to see your aggregate.

    Reasons For

    1 perspective
    Reason for
    ?
    • 1.For a causal curve of the type in question to reach Σ₀, it must first intersect H⁺(Σ₀).
      ?

      Think about whether this reason is strong or weak

    • 2.Once a curve reaches H⁺(Σ₀), it can be continued endlessly into the past without meeting Σ₀.
      ?

      Think about whether this reason is strong or weak

    • 3.The generators of H⁺(Σ₀) are past endless null geodesics that never meet Σ₀.
      ?

      Think about whether this reason is strong or weak

    Reasons Against

    2 perspectives
    Reason against 1 of 2
    ?
    • 1.Thornian time machines, built on exotic matter threading a wormhole, require H⁺(Σ₀) generators that are past-endless by construction.
      ?

      Think about whether this reason is strong or weak

    • 2.A formation condition demanding causal curves intersect Σ₀ conflates the boundary of causal development with the origin of the time machine itself.
      ?

      Think about whether this reason is strong or weak

    • 3.Earman, Smeenk, and Wüthrich's own analysis shows no locally constructed time machine can satisfy this intersection condition without begging the question against wormhole topologies.
      ?

      Think about whether this reason is strong or weak

    Reason against 2 of 2
    ?
    • 1.The global hyperbolicity framework presupposes a topology that Thornian spacetimes explicitly violate, making Σ₀-intersection a category error when applied to them.
      ?

      Think about whether this reason is strong or weak

    • 2.Requiring past-endless null geodesics to meet Σ₀ imposes a Cauchy-development standard that Morris and Thorne's construction never claimed to satisfy, targeting a straw man.
      ?

      Think about whether this reason is strong or weak

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