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Linglib.Theories.Semantics.Causation.CausalVerb

Causal Verb Frame #

@cite{nadathur-2023} @cite{nadathur-lauer-2020}

Deep foundation for complement-entailing constructions: implicative verbs (manage, fail), ability modals (be able), and degree constructions (enough/too). Analogous to MereoDim bridging mereology and scales, this file bridges causation, modality, and aspect through a single parameterized frame.

The Unifying Abstraction #

All three phenomena share the same causal skeleton:

  1. A causal dynamics (structural equations)
  2. A trigger variable (action, degree threshold, managing event)
  3. A complement variable (the VP outcome)
  4. A background function mapping evaluation contexts to causal situations
  5. An actualization mode controlling what asserts trigger occurrence

The actuality inference in all cases reduces to the same syllogism:

Closure-Operator Structure (§1) #

For positive dynamics, normalDevelopment is a closure operator on (Situation, trueLE):

  1. Inflationary: s ⊑ cl(s) — adding causal consequences only adds truths
  2. Monotone: s₁ ⊑ s₂ → cl(s₁) ⊑ cl(s₂) — more inputs → more outputs
  3. Idempotent: cl(cl(s)) = cl(s) — fixpoint stability

Causal sufficiency is closure membership: complement = true ∈ cl(s + trigger). This is the deep structural reason that all three phenomena work the same way.

Linguistic Instances (§5–§6) #

InstanceTriggerAspect-governed?
managemanaging eventNo (lexical)
be ableagent's actionYes (PFV/IMPF)
enough to VPdegree ≥ θYes (PFV/IMPF)
too Adj to VPdegree ≥ θYes (PFV/IMPF)

For positive dynamics, normalDevelopment satisfies the three closure operator axioms. The inflationary and monotonicity properties are proved in Core/Causation.lean; we package them here and add the fixpoint return.

Causal sufficiency as closure membership.

causallySufficient dyn s trigger complement holds iff complement = true ∈ cl(s + {trigger = true}).

This is definitional — we state it as a theorem for the conceptual bridge: sufficiency IS asking whether the complement is in the closure of the extended situation.

How the actuality of the trigger gets asserted.

  • lexical: The verb's lexical semantics asserts that the trigger occurred. The complement entailment holds regardless of grammatical aspect. (manage, fail, force, prevent)

  • aspectual: Grammatical aspect determines whether the trigger's occurrence is asserted. Perfective asserts it; imperfective doesn't. (be able, enough to VP, too Adj to VP)

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      CausalFrame: The abstract frame underlying all complement-entailing verb constructions.

      Parameterized by W (evaluation context type):

      • W = Unit for implicative verbs (no modal dimension)
      • W = World for ability modals (Kripke worlds)
      • W = World for degree constructions (degree evaluated at worlds)

      The frame bundles:

      • Causal model (dynamics + trigger + complement)
      • Background projection (evaluation context → causal situation)
      • Actualization mode (what controls trigger assertion)

      All three phenomena are instances differing only in the choice of W, actualization, and what the "trigger" represents.

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        Trigger is causally sufficient for complement at evaluation context w.

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          Complement is actualized at w: trigger occurred AND complement developed.

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            The complement did NOT develop at w (for negative-polarity verbs like fail, too Adj to VP).

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              Generic actuality predicate with aspectual modulation.

              • Lexical: sufficiency AND actualization (always, regardless of aspect)
              • Aspectual + perfective: sufficiency AND actualization
              • Aspectual + imperfective: sufficiency only (no actualization required)

              This is the single function from which manageSem, abilityWithAspect, and enoughWithAspect are all derived.

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                Generic actuality theorem (lexical mode): if a lexically-actualized frame holds, the complement is actualized.

                This is the abstract version of manage_entails_complement.

                Generic actuality theorem (aspectual + perfective): if an aspect-governed frame holds with perfective aspect, the complement is actualized.

                This is the abstract version of perfective_ability_entails_complement and perfective_enough_entails_complement.

                Generic non-entailment (aspectual + imperfective): imperfective aspect is compatible with complement not being actualized.

                This is the abstract version of imperfective_ability_compatible_with_unrealized.

                Aspect governs actuality (generic): the same frame yields different entailment patterns under different aspects, demonstrated with a frame over Bool where true = action performed, false = not.

                Abstract version of aspect_governs_actuality.

                Lexical mode is aspect-independent: the result is the same for perfective and imperfective when the trigger is present.

                This captures "manage" being aspect-independent: the entailment doesn't change with aspect because the lexical semantics already asserts trigger occurrence.

                Show that existing structures are instances of CausalFrame.

                An ImplicativeScenario is a CausalFrame Unit with lexical actualization.

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                  An AbilityScenario is a CausalFrame World with aspectual actualization.

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                    Grounding theorem: the generic actualityWithAspect matches abilityWithAspect for ability scenarios.

                    This is the key structural result: Ability.lean's hand-written abilityWithAspect is exactly what falls out of the generic CausalFrame.actualityWithAspect machinery.

                    Causal sufficiency in a frame is monotone for positive dynamics: adding truths to the background preserves sufficiency.

                    This is the frame-level version of sufficiency_monotone_positive.