Speech Act Logic

Origin. Searle, Vanderveken (1985). Illocutionary logic. Force and content. Speech act theory formalized. Foundation of pragmatic logic.

Models. Illocutionary forces. Propositional contents. Felicity conditions. Success and satisfaction.

Formalism.

Illocutionary act: F(P): force F applied to content P. F: illocutionary force. P: propositional content.

Force components: Illocutionary point. Degree of strength. Mode of achievement. Content conditions. Preparatory conditions. Sincerity conditions.

Basic forces: ⊢: assertion (commit to truth). !: directive (attempt to get hearer to act). ↓: commissive (commit speaker to act). ↑: declarative (make it so). ♡: expressive (express attitude).

Success conditions: F(P) successful iff: Propositional content conditions met. Preparatory conditions hold. Speaker has required intentions. Hearer recognizes intention.

Satisfaction: F(P) satisfied iff: World matches direction of fit. Assertions: P true. Directives: hearer does P. Commissives: speaker does P.

Direction of fit: Word-to-world: assertions (↓). World-to-word: directives, commissives (↑). Both: declarations. Neither: expressives.

Illocutionary entailment: F₁(P) ⊢ F₂(Q) if success of F₁(P) implies success of F₂(Q). Promise entails commitment.

Indirect speech acts: Literal force ≠ intended force. "Can you pass the salt?" = request. Pragmatic inference.

Symbols.

Symbol	Unicode	Meaning
F(P)	—	illocutionary act
⊢	U+22A2	assertion force
!	—	directive force
↓	U+2193	commissive force

Metatheory. Illocutionary forces. Success conditions. Satisfaction. Direction of fit.

Applies to. Pragmatics. Communication. Agent interaction. Natural language.

Limitations. Idealization. Force individuation. Context sensitivity. Indirect acts complex.