Documentation

Studies.CaoWhiteLassiter2025

Cao, White and Lassiter (2025): Cause, make, and force as graded causatives #

Cao, White and Lassiter treat English cause, make and force as graded causatives. Where Nadathur and Lauer give make a categorical truth condition, causal sufficiency, they measure three quantities in a structural causal model of tic-tac-toe: Pearl's probability of sufficiency (suf), a simplified version of Halpern and Kleiman-Weiner's degree of intention, and the number of alternative actions open to the causee. No one quantity determines which verb speakers accept; each verb has its own set of reliable interactions. As in the model of Cao, Geiger, Kreiss, Icard and Gerstenberg, the models are time-indexed (TimeIndex) and their agents play a soft-optimality policy.

The paper's in-text judgments, its examples (3)–(11), are rows in Data/Examples/CaoWhiteLassiter2025.json; the regression estimates stay in prose.

Main statements #

References #

Soft-optimality policy #

The paper's mechanism for agent moves (§2.1.1). The highest-utility move — minimax over the game tree, with terminal utility Winner × (EmptySpace + 1) — is taken with probability ρ + (1−ρ)/n and every other available move with (1−ρ)/n, for n the number of empty spaces. The skill parameter interpolates between a uniformly random player ("assume that the players are infants"), under which the paper's worked SUF contrast between two board states collapses, and a deterministic professional.

noncomputable def CaoWhiteLassiter2025.softOptimalPolicy {A : Type u_1} [MeasurableSpace A] (best : A) (ρ : ENNReal) :
MeasureTheory.Measure A

A player of skill ρ plays the highest-utility move best with probability ρ and otherwise a uniform random move.

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    theorem CaoWhiteLassiter2025.isProbabilityMeasure_softOptimalPolicy {A : Type u_1} [MeasurableSpace A] (best : A) (ρ : ENNReal) [Finite A] [Nonempty A] (hρ : ρ ≤ 1) :
    MeasureTheory.IsProbabilityMeasure (softOptimalPolicy best ρ)
    theorem CaoWhiteLassiter2025.softOptimalPolicy_zero {A : Type u_1} [MeasurableSpace A] (best : A) :
    softOptimalPolicy best 0 = ProbabilityTheory.uniformOn Set.univ
    theorem CaoWhiteLassiter2025.softOptimalPolicy_one {A : Type u_1} [MeasurableSpace A] (best : A) :
    softOptimalPolicy best 1 = MeasureTheory.Measure.dirac best
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    theorem CaoWhiteLassiter2025.softOptimalPolicy_singleton_best {A : Type u_1} [MeasurableSpace A] (best : A) (ρ : ENNReal) [Fintype A] [MeasurableSingletonClass A] :
    (softOptimalPolicy best ρ) {best} = ρ + (1 - ρ) / ↑(Fintype.card A)
    @[simp]
    theorem CaoWhiteLassiter2025.softOptimalPolicy_singleton_of_ne {A : Type u_1} [MeasurableSpace A] (best : A) (ρ : ENNReal) [Fintype A] [MeasurableSingletonClass A] {a : A} (h : a ≠ best) :
    (softOptimalPolicy best ρ) {a} = (1 - ρ) / ↑(Fintype.card A)

    The ALT measure #

    ALT (§2.2) counts the alternative actions available to the causee, excluding the one actually taken — ALT(Y₁) = 5 at the paper's fig. 2a board state. ALT = 0 is the Frankfurt-style could-not-have-done-otherwise configuration.

    noncomputable def CaoWhiteLassiter2025.altCount {A : Type u_1} (taken : A) [MeasurableSpace A] (μ : MeasureTheory.Measure A) :
    ℕ

    The number of alternative actions available to the causee is the number of actions of positive probability other than the one taken.

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      theorem CaoWhiteLassiter2025.altCount_eq_zero_iff {A : Type u_1} [Fintype A] (taken : A) [MeasurableSpace A] (μ : MeasureTheory.Measure A) :
      altCount taken μ = 0 ↔ ∀ (a : A), a ≠ taken → μ {a} = 0

      The causee had no alternative exactly when every other action had probability zero.

      The INT measure #

      The paper's §2.3 displayed equation, a simplified [HKW18] degree of intention:

      INT(a) = Pr(A = a ∧ G) · u′(a) / Σ_{a′} Pr(A = a′ ∧ G) · u′(a′)

      "the probability that an action performed in a state will result in the desired outcome, normalized by the probability of all alternative actions that would have resulted in the same outcome", each term weighted by exponentiated utility u′ = eᵘ, the exponential serving only to make the weights strictly positive. Here pr a′ is the joint probability that the agent takes a′ and the goal results, and the weight is abstracted to any w : A → ℝ≥0; modelIntention instantiates pr over a SEM.

      The simplification costs the principle it is motivated by: [HKW18] hold, after [Fra69], that an action an agent could not have avoided is never intentional, while under this measure such an action is maximally intentional, its sole goal-conducive alternative being itself. It is ALT rather than INT that registers the paper's made/forced contrast in (8).

      noncomputable def CaoWhiteLassiter2025.intentionDegree {A : Type u_1} [Fintype A] (pr : A → ENNReal) (w : A → NNReal) (a : A) :
      ENNReal

      The goal-weighted share of action a among all goal-conducive alternatives.

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        theorem CaoWhiteLassiter2025.intentionDegree_le_one {A : Type u_1} [Fintype A] (pr : A → ENNReal) (w : A → NNReal) (a : A) :
        intentionDegree pr w a ≤ 1

        INT is a share, so it never exceeds 1.

        theorem CaoWhiteLassiter2025.intentionDegree_eq_one_of_no_alternatives {A : Type u_1} [Fintype A] (taken : A) (pr : A → ENNReal) (w : A → NNReal) (h : ∀ (a : A), a ≠ taken → pr a = 0) (h0 : pr taken ≠ 0) (hw : w taken ≠ 0) (htop : pr taken ≠ ⊤) :
        intentionDegree pr w taken = 1

        An action that is the only goal-conducive one carries the whole normalized weight.

        theorem CaoWhiteLassiter2025.intentionDegree_eq_one_of_altCount_eq_zero {A : Type u_1} [Fintype A] (taken : A) (pr : A → ENNReal) (w : A → NNReal) [MeasurableSpace A] (μ : MeasureTheory.Measure A) [MeasureTheory.IsFiniteMeasure μ] (hle : ∀ (a : A), pr a ≤ μ {a}) (h : altCount taken μ = 0) (h0 : pr taken ≠ 0) (hw : w taken ≠ 0) :
        intentionDegree pr w taken = 1

        An agent who could not have done otherwise comes out maximally intentional, since the simplified INT does not carry the alternative-possibilities condition; ALT is what separates made from forced.

        noncomputable def CaoWhiteLassiter2025.modelIntention {U : Type u_1} {V : Type u_2} {α : V → Type u_3} [MeasurableSpace U] (M : CausalModel U V α) [M.IsAcyclic] [∀ (v : V), Nonempty (α v)] (ν : MeasureTheory.Measure U) (I : (v : V) → Flat (α v)) (act : V) [Fintype (α act)] (goal : Set ((v : V) → α v)) (w : α act → NNReal) (a : α act) :
        ENNReal

        The paper's INT over a causal model instantiates intentionDegree with pr a′ the probability, over contexts drawn from ν, that under the intervention I the action variable takes the value a′ and the outcome satisfies the goal: the paper's Pr((M,u⃗) ⊨ A = a⃗′ ∧ G = g⃗).

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          noncomputable def CaoWhiteLassiter2025.suf {U : Type u_1} {V : Type u_2} {α : V → Type u_3} [DecidableEq V] [MeasurableSpace U] (M : CausalModel U V α) [M.IsAcyclic] [∀ (v : V), Nonempty (α v)] (ν : MeasureTheory.Measure U) (obs : (v : V) → Flat (α v)) (c : V) (x : α c) (e : V) (y : α e) :
          ENNReal

          SUF, Pearl's probability of sufficiency ([Pea19]), is the probability, among the contexts drawn from ν in which the observation obs holds, that setting c := x makes e = y.

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            theorem CaoWhiteLassiter2025.suf_bot {U : Type u_1} {V : Type u_2} {α : V → Type u_3} [DecidableEq V] [MeasurableSpace U] {M : CausalModel U V α} [M.IsAcyclic] [∀ (v : V), Nonempty (α v)] (ν : MeasureTheory.Measure U) [MeasureTheory.IsProbabilityMeasure ν] (c : V) (x : α c) (e : V) (y : α e) :
            suf M ν ⊥ c x e y = ν {u : U | M.solve (Function.update ⊥ c ↑x) u e = y}

            With nothing observed, SUF is the probability that the intervention yields the effect.

            Deterministic limit #

            With a certain context SUF collapses to a {0,1} indicator, and wherever Nadathur and Lauer's categorical make holds of the empty background, SUF is 1 whatever the distribution over contexts. The converse fails: a single context can make the intervention yield the effect without the effect being settled by the strict development, so the categorical make semantics is strictly stronger than maximal graded SUF.

            theorem CaoWhiteLassiter2025.suf_dirac {U : Type u_1} {V : Type u_2} {α : V → Type u_3} [DecidableEq V] [MeasurableSpace U] {M : CausalModel U V α} [M.IsAcyclic] [∀ (v : V), Nonempty (α v)] [MeasurableSingletonClass U] (u₀ : U) (c : V) (x : α c) (e : V) (y : α e) :
            suf M (MeasureTheory.Measure.dirac u₀) ⊥ c x e y = if M.solve (Function.update ⊥ c ↑x) u₀ e = y then 1 else 0

            With a certain context, SUF is the indicator of the counterfactual outcome there.

            theorem CaoWhiteLassiter2025.suf_eq_one_of_make {U : Type u_1} {V : Type u_2} {α : V → Type u_3} [DecidableEq V] [MeasurableSpace U] {M : CausalModel U V α} [M.IsAcyclic] [∀ (v : V), Nonempty (α v)] (ν : MeasureTheory.Measure U) [MeasureTheory.IsProbabilityMeasure ν] {u₀ : U} {c e : V} {x : α c} {y : α e} (h : NadathurLauer2020.Make M ⊥ u₀ c x e y) :
            suf M ν ⊥ c x e y = 1

            Nadathur and Lauer's make entails maximal SUF. Whenever make holds of the empty background, SUF is 1 under every distribution over contexts.

            structure CaoWhiteLassiter2025.TimeIndex {U : Type u_1} {V : Type u_2} {α : V → Type u_3} (M : CausalModel U V α) :
            Type u_2

            A time index for a causal model (the paper's definition 1) places each parent exactly one timestep before its child.

            • time : V → ℕ

              The timestep of each variable.

            • parent_succ {w v : V} : M.graph.Adj w v → self.time w + 1 = self.time v

              Parents immediately precede their children.

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              theorem CaoWhiteLassiter2025.TimeIndex.isAcyclic {U : Type u_1} {V : Type u_2} {α : V → Type u_3} {M : CausalModel U V α} (ti : TimeIndex M) :

              A time-indexed model is acyclic.

              The paper's judgment data #

              The in-text contrasts are rows in Data.Examples.CaoWhiteLassiter2025: the non-interchangeability triplets (3)–(4), the gym gradability triplets (5)–(7), the could-have-done-otherwise pair (8), the intent-denial continuations (9)–(10), and the make/let sufficiency pair (11).

              The paper's (8) separates make from force. In one frame with a could-have-done-otherwise continuation, made tolerates the continuation and forced resists it, a difference in the causee's alternatives, which ALT measures.

              The gym triplets (5)–(7) grade the stronger verbs against a constant cause. The same three causing events leave caused acceptable throughout while forced switches, which is why the account measures the causal relation rather than classifying it.

              A probabilistic model #

              SUF is a probability when the background is uncertain. In a model whose effect holds when the cause and a background noise both do, and whose noise is true with probability p, setting the cause makes the effect true with probability p, strictly between the 0 and 1 of the categorical semantics.

              The vertices are the cause, the background noise, and the effect.

              • cause : V
              • noise : V
              • effect : V
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                  The effect reads the cause and the noise.

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                    The effect holds when the cause and the noise both do; the context settles the noise, and the cause is off unless set.

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                      The model is time-indexed in the sense of the paper's definition 1, with cause and noise at step 0 and effect at step 1.

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                        noncomputable def CaoWhiteLassiter2025.ProbabilisticExample.background (p : ENNReal) :
                        MeasureTheory.Measure Bool

                        In the background the noise is true with probability p.

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                          theorem CaoWhiteLassiter2025.ProbabilisticExample.effect_iff (b : Bool) :
                          model.solve (Function.update ⊥ V.cause ↑true) b V.effect = true ↔ b = true

                          Setting the cause, the effect holds exactly when the noise is true.

                          theorem CaoWhiteLassiter2025.ProbabilisticExample.suf_eq {p : ENNReal} (hp : p ≤ 1) :
                          suf model (background p) ⊥ V.cause true V.effect true = p

                          SUF is the probability of the noise, graded as the paper's measure requires.