Foundations of Illocutionary Logic
Reference: Searle & Vanderveken (1985). Cambridge University Press. Source file: 5F9BF68C-E1C8-11EE-931A-C444DB61CCB4.pdf. URL
Summary
Searle and Vanderveken construct a formalized logic of speech acts, filling the gap between philosophy of language and formal logic. The book recursively defines the space of illocutionary forces from five primitives (assertive, commissive, directive, declarative, expressive) via seven components of illocutionary force (illocutionary point, mode of achievement, propositional-content conditions, preparatory conditions, sincerity conditions, degree of strength, direction of fit).
It develops axiomatic propositional illocutionary logic, laws of illocutionary entailment, commitment, negation, conjunction, and conditionalization, and closes with a semantic analysis of over a hundred English performative verbs. The work is foundational for agent communication languages because it gives a rigorous semantics to the performatives (inform, request, promise, declare, etc.) later adopted by KQML and FIPA-ACL.
Key Ideas
- Five illocutionary points: assertive, commissive, directive, declarative, expressive.
- Seven components of illocutionary force.
- Direction of fit: word-to-world vs world-to-word.
- Formal calculus of success conditions and illocutionary entailment.
- Semantic definitions of English performative verbs.
Connections
Conceptual Contribution
- Claim: The space of possible speech acts is generated recursively from five illocutionary points and seven components of illocutionary force, and admits a genuine formal logic of success and entailment.
- Mechanism: Axiomatic propositional illocutionary logic: laws of illocutionary entailment, commitment, negation, conjunction, and conditionalisation; closes with semantic definitions of over a hundred English performative verbs.
- Concepts introduced/used: Speech Act Theory, Performatives, Illocutionary Force, Direction of Fit, Sincerity Conditions, Preparatory Conditions, Commitment-based Semantics, Mental State, Mentalistic Semantics
- Stance: foundational / formal-semantic
- Relates to: Supplies the philosophical semantics imported by KQML Language And Protocol and FIPA-ACL, and re-examined publicly in Agent Communication And Institutional Reality and A Common Ontology Of ACLs.
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