Documentation

Linglib.Theories.Semantics.Modality.ActualityEntailments

Actuality Entailments: Position × Aspect #

@cite{hacquard-2006} @cite{hacquard-2009} @cite{bhatt-1999}

Derives actuality entailments from the relative scope of aspect and modal, building on event-relative modality (EventRelativity.lean).

The Puzzle #

The same modal verb shows different entailment patterns depending on interpretation (@cite{bhatt-1999}, @cite{hacquard-2006} Ch.1):

@cite{hacquard-2006}'s Solution #

The relative position of the modal determines which event binder captures it:

Content Licensing Explains the Asymmetry #

WHY are epistemic modals always above aspect? Content licensing (EventRelativity §8): epistemic modal bases require a contentful event. VP events lack content. Therefore epistemic modals cannot be bound by aspect — they must be above AspP. Root modals need only circumstantial backgrounds (any event type), so they CAN be below AspP.

The actuality entailment asymmetry follows from content licensing + aspect scope, without stipulation.

The earlier CausalFrame-bridge §4 (showing actualityWithAspect .perfective matches sufficientAt ∧ actualizedAt) was deleted in Phase D-H along with the CausalFrame/ComplementEntailing substrate; the qualitative bridge to @cite{nadathur-2023}'s causal account now lives at the V2 SEM level in study files and Semantics/Causation/.

The relative scope of aspect and the modal in the clause structure.

Root modals are below AspP: aspect quantifies over the modal event. Epistemic modals are above AspP: the modal quantifies over aspect.

This structural difference — not lexical semantics — is the sole source of the actuality entailment asymmetry.

  • aspectOverModal : AspectModalScope

    Root: [Asp [Mod [VP]]] — aspect scopes over modal

  • modalOverAspect : AspectModalScope

    Epistemic: [Mod [Asp [VP]]] — modal scopes over aspect

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      Whether the theory predicts an actuality entailment for a given position × aspect combination.

      Only root + perfective yields an actuality entailment:

      PositionAspectAE?Why
      root (below Asp)PFVAsp > Mod: PFV forces completion
      root (below Asp)IMPFAsp > Mod: IMPF doesn't force completion
      epistemic (above Asp)PFVMod > Asp: PFV in accessible worlds only
      epistemic (above Asp)IMPFMod > Asp: no completion
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        Only root + perfective yields actuality entailments. This is a characterization result: AE ↔ (belowAsp ∧ perfective).

        The prediction aligns with the aspect scope story: AE holds exactly when aspect scopes over the modal AND aspect is perfective.

        The same lexical modal yields different actuality patterns depending solely on position. This is Hacquard's core argument against lexical ambiguity: French pouvoir, Greek boro, Hindi saknaa are single lexical items whose actuality behavior is structurally determined.

        WHY are epistemic modals always above aspect? Content licensing (EventRelativity §8) provides the answer:

        The chain: content licensing → position → scope → (no) AE.

        The actuality entailment pattern results from the interaction of content licensing, syntactic position, and viewpoint aspect.

        This theorem chains together:

        • EventRelativity §8 (content licensing determines available flavors)
        • EventRelativity §9 (position determines event binder)
        • This file §1–2 (position determines aspect scope → AE prediction)

        The causal-model validation of the root + PFV case (formerly via CausalFrame/ComplementEntailing) is now witnessed at the V2 SEM level in study files.