Illocutionary Force

The kind of act a speaker performs in uttering something — asserting, promising, ordering, questioning — as distinguished from the propositional content. Searle and Vanderveken decompose force into components such as point, direction of fit and sincerity conditions.

In this vault

Backlinks

Foundations Of Illocutionary Logic line 26
Semantics and Conversations for an ACL line 30
Direction of Fit line 8
Speech Acts line 9
Preparatory Conditions line 7

Linked Pages

Direction of Fit

Searle and Anscombe’s distinction between mental/speech-act types according to whether the mind (or word) is meant to match the world (word-to-world, as in assertions and beliefs) or the world is meant to match the mind (world-to-word, as in commands and desires).

In this vault

Speech Act Theory

Philosophy-of-language framework (Austin, Searle, Vanderveken) in which utterances perform actions (illocutionary acts) — the semantic backbone of most Agent Communication Languages.

Sources

Foundations Of Illocutionary Logic — Searle & Vanderveken
Three Models for the Description of Language — Chomsky, foundations
Agent Communication And Institutional Reality

Applied in

Foundations Of Illocutionary Logic

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.