An Ontology for Commitments in Multiagent Systems: Toward a Unification of Normative Concepts

Reference: Singh, M. P. (1999). An Ontology for Commitments in Multiagent Systems: Toward a Unification of Normative Concepts. Artificial Intelligence and Law 7(1): 97–113. Kluwer. DOI · Author copy via Academia.edu · Singh publications (NCSU)

Summary

This paper is the formal core of Singh’s commitment-based programme — a piece that sits between the polemical Rethinking the Principles (1998) and the operationalised commitment machines line (Yolum & Singh 2002). Singh argues that the multiplicity of normative concepts used across MAS, deontic logic, and law — obligation, permission, prohibition, promise, contract, delegation, cancellation, release — can be unified by taking the social commitment as the basic ontological primitive and reconstructing the rest as patterns over commitments. A social commitment is a four-place relation: a debtor is committed to a creditor for the fulfilment of some condition in the context of a particular institution or social scope. Once these four roles are fixed, the standard normative operations — create, discharge, cancel, release, delegate, assign — become commitment-state transitions, and the deontic vocabulary becomes a derived layer over the commitment substrate.

The construction is deliberately public: commitments live in the social state, not in the heads of any agent. A commitment exists when a publicly observable act has created it (a promise speech act, a contract signing, an assertion under appropriate sincerity context); it persists until a publicly observable act has discharged or cancelled it. The truth-conditions for “agent A is committed” are externally checkable: they reference the social record, not A’s mental state. This is the exact alternative to the mentalistic semantics of FIPA / Cohen and Levesque 1995 that Rethinking the Principles called for. The paper also sets up the bridge to law: Singh notes the close fit with Jones and Sergot’s “count-as” relation, with deontic logic, and with the speaks-for tradition in distributed systems — establishing commitments as a unifying normative substrate across philosophy, law, MAS, and computer security.

For CBCL and the broader public-semantics line, this is the ontology document: it defines what “commitment” means precisely enough that protocol designers can map performatives onto commitment-state transitions and verifiers can monitor compliance from a transcript. The four-place structure (debtor, creditor, condition, context) maps almost directly onto the ledger-of-commitments architecture in Fornara & Colombetti 2004 and the dialect contracts in CBCL. The paper is also the place to cite when arguing that commitment-based ACL semantics is not merely a behavioural surrogate but a real normative theory with established connections to legal and deontic logic.

Key Ideas

Commitment as the primitive normative concept: a four-place relation C(debtor, creditor, condition, context) — agent x is committed to agent y for the fulfilment of condition q in the social context s. The four roles must always be specified; commitments without a creditor are degenerate.
Standard commitment operations: create (a new commitment comes into being via a public act), discharge (the condition is satisfied), cancel (the debtor unilaterally retracts, possibly incurring meta-commitment), release (the creditor waives), delegate (the debtor passes the obligation to a third party with creditor consent), assign (the creditor passes the entitlement).
Conditional commitments: CC(x, y, p ⊃ q, s) — x is committed to y to bring about q if p holds. The conditional structure handles contracts, contingent obligations, and protocol-state dependencies.
Discharge by satisfaction: a commitment is discharged when its condition is satisfied (in the relevant social interpretation); discharge is monotone — once discharged, the commitment is closed.
Deontic vocabulary as derived: obligation, permission, prohibition, right, and duty are reconstructable from commitment patterns plus the relevant institutional context.
Public, externally checkable semantics: commitments are facts about the social record, not about agent mental states. Verification is by inspection of the transcript and the institutional rules.
Bridges to legal informatics and deontic logic: the framework is explicitly compatible with Jones and Sergot’s count-as relation and with classical deontic-logic operators, positioning commitments as the unifier across philosophy, law, MAS, and distributed-security normative reasoning.

Connections

Conceptual Contribution

Claim: The proliferation of normative concepts across MAS, deontic logic, and law can be unified by taking the social commitment — a four-place relation C(debtor, creditor, condition, context) — as the basic primitive and reconstructing obligation, permission, prohibition, contract, and delegation as commitment patterns. Commitments are public: their existence is determined by observable acts and observable conditions, not by agent mental states.
Mechanism: Define commitments as four-place relations (debtor / creditor / condition / context) and conditional commitments analogously. Specify the operations create / discharge / cancel / release / delegate / assign as commitment-state transitions. Show how standard deontic-logic operators and standard legal concepts (promise, contract, breach, novation) reduce to patterns over these primitives. Sketch the bridge to Jones and Sergot’s count-as analysis of institutional facts.
Concepts introduced/used: Social Commitment, Conditional Commitment, Commitment Operations (create / discharge / cancel / release / delegate / assign), Debtor, Creditor, Condition, Context (Commitment), Deontic Reduction.
Stance: foundational technical paper / unifying ontology.
Relates to: The formal statement of the programme Singh 1998 argued for polemically; the bridge to the operational accounts in Yolum & Singh 2002, Yolum & Singh 2002b, and Fornara & Colombetti 2004. The philosophical complement is Brandom: Singh’s commitments are precisely the commitment leg of Brandom’s deontic scorekeeping triple. The legal complement is Jones & Sergot 1993 — count-as gives the institutional grounding for what makes a publicly observable act count as creating a commitment. The distributed-systems complement is the speaks-for tradition (Lampson et al. 1992) — credentials and delegated assertion authority are commitment patterns of the same family. CBCL’s dialect contracts and verdict ledger directly instantiate this ontology at wire-format granularity.

Tags

#singh #commitments #commitment-based-semantics #ontology #normative #public-semantics #acl #deontic #foundations

Backlinks

Linked Pages

CBCL - Safe Self-Extending Agent Communication

CBCL: Safe Self-Extending Agent Communication

Reference: O’Connor, H. (2026). LangSec Workshop, IEEE Security and Privacy Workshops (SPW 2026). arXiv:2604.14512v1 [cs.CR], 16 Apr 2026. Source file: oconnor-cbcl-langsec26.pdf. URL. Reference implementation: https://codeberg.org/anuna/cbcl-rs.

Summary

Building on McCarthy’s 1975/1982 Common Business Communication Language vision and the language-theoretic security programme of Sassaman, Patterson, Bratus and Locasto (Security Applications Of Formal Language Theory), this paper presents a contemporary CBCL: an agent communication language designed so that all messages — including runtime language extensions — remain within the deterministic context-free (DCFL) complexity class. The motivating diagnosis is that contemporary agent communication has slid up the Chomsky hierarchy without acknowledging the security cost: KQML and FIPA-ACL are CFL with informal extensibility, but MCP and LLM-based agent frameworks operate over inputs whose effective complexity is recursively-enumerable, where the validity of an arbitrary message is undecidable and “weird machines” (Exploit Programming - From Buffer Overflows To Weird Machines) become unavoidable. CBCL takes the opposite tack: minimal core (8 performatives — tell, ask, reply, hello, bye, ok, error, cancel) plus a homoiconic dialect mechanism that lets agents define, transmit, and adopt domain-specific vocabularies as first-class CBCL messages, with three machine-checked safety invariants — R1 (no recursion in dialect templates), R2 (declared resource bounds on depth, expansion size, verification time), R3 (core-vocabulary preservation) — that together guarantee DCFL preservation under arbitrary finite sequences of dialect installations.

The paper accompanies the design with a Lean 4 formalization (≈5,400 lines, 16 modules, 176 machine-checked theorems, zero sorry gaps, no custom axioms) covering parser correctness (soundness + completeness), R1–R3 verification, pipeline totality, and the central dcfl_preserved closure theorem; a verified parser binary cbcl-parse is extracted from the proofs. A separately-developed Rust reference implementation (cbcl-rs, ≈11,000 lines, no_std-compatible core) ships a hand-rolled O(n) parser, dialect verification engine, gossip-based dialect propagation (O(log n) convergence per Demers et al.), C FFI/WASM bindings, property-based and differential tests, and cargo-fuzz targets; differential tests cross-validate the Rust parser against the Lean-extracted binary, eliminating spec-implementation parser differentials. Five example dialects (precision agriculture, AI planning, cross-chain asset transfer, artifact management, email) are R1–R3-verified end-to-end. A draft IETF Internet-Draft specifying application/cbcl and a Nostr transport binding (cbcl-nostr) accompany the paper. The Discussion explicitly aligns the design with Singh’s social-agency programme: dialect installation is treated as a public commitment to the dialect’s declared semantics — semantic divergence becomes a breach of commitment, observable and accountable, rather than a hidden failure of shared mental state — sidestepping the unverifiable mentalistic semantics critique of Verifiable Semantics for ACLs.

Implementation status (post-paper, cbcl-rs). The reference implementation has shipped two further safety invariants the paper sketches as future work, plus a richer Lean formalisation: R4 (Integrity) — Ed25519-style signatures over canonical encodings via an algorithm-agnostic Signer trait, with three-valued install verdicts (Valid / Unsigned / Invalid) — and R5 (Contract Well-formedness) — optional (protocol …) and (shape …) clauses on a dialect, expressing causal Merkle DAG protocols and per-performative shape contracts; R5 enforces acyclicity, reachability from begin, performative definedness with ancestor closure for extends, step uniqueness, and depth-bound respect, all decidable in linear fuel at install time. The §VII-D structural-contracts vision is therefore live (SPEC-002, SPEC-003): verify_monotone, verify_all_is_meet, and verify_eventually_consistent are proved theorems showing causal-protocol verification is a lattice homomorphism that joins coordination-free under G-Set store merge — explicit CALM Theorem alignment. The Lean codebase has grown to 380+ declarations across 19 files (still zero sorry, only the standard axioms propext / Classical.choice / Quot.sound); the workspace ships 837 tests including 584 cbcl-core unit tests, 37 proptest cases, 21 differential integration tests against the Lean-extracted binary, libFuzzer harnesses, and cargo-mutants mutation testing at a 90% kill threshold. The crate layout has grown from the paper’s five to seven: the original cbcl-core / cbcl-parser / cbcl-cli / cbcl-wasm / cbcl-ffi plus cbcl-erl (Erlang/LFE binding, SPEC-009 — with SPEC-010 binding-conformance suite) and cbcl-arena (Agent Arena platform, SPEC-012 — composable referee on cbcl-lfe-router with capability-keyed message routing and signed receipt logs). A worked sealed-bid auction dialect (SPEC-004) demonstrates structural defence against false-claim manipulation — concrete evidence that the R5 contract layer is rich enough to encode mechanism-design integrity properties decidably. The earlier Scheme prototype (anuna-research/cbcl) is superseded; architecture decisions live as ADRs under .hence/ (purity boundary, parser library choice, error handling, WASM API surface, R4 adversarial review).

Key Ideas

DCFL as the Goldilocks complexity class: Regular is too weak for nested envelopes/dialects; general CFL admits ambiguous grammars and parser-differential attacks; context-sensitive is PSPACE-complete; Type-0 is undecidable. DCFL is the minimal class that supports nested structure with class-level unambiguity (parser equivalence under language evolution).
Homoiconic self-extension: Dialect definitions are themselves valid CBCL messages, parsed by the same recogniser used for ordinary communication — a single attack surface, no separate meta-language. Inspired by Racket’s #lang mechanism.
Three safety invariants R1–R3: declarative pattern-template substitution only (no recursion, no iteration, no reflection); declared resource bounds (depth ≤ 64, expansion ≤ 8192 chars, verification ≤ 1000 ms); the eight core performatives cannot be redefined.
DCFL preservation theorem: dialect invocations must appear inside a (lang name …) wrapper; the lang tag plus a unique dialect name forms a prefix-free partition that lets a deterministic pushdown automaton dispatch to the appropriate subgrammar without extra lookahead — circumventing the fact that DCFLs are not closed under union in general. Mechanised in Lean 4 as dcfl_preserved.
Lean 4 formalization with extraction: 176 theorems, 0 sorry gaps, no custom axioms; the verified parser binary cbcl-parse is extracted from the proofs and runs the same fuel-bounded recursive-descent parser as the model.
Rust reference implementation: cbcl-core (no_std, no unsafe), cbcl-parser, cbcl-cli, cbcl-ffi, cbcl-wasm. Differential tests against the Lean-extracted binary; cargo-fuzz over five entry points.
Eight core performatives (tell, ask, reply, hello, bye, ok, error, cancel) plus four message categories (simple, meta, lang-scoped, wrapped); keyword parameters in Common-Lisp style (:thread, :in-reply-to).
Single-pass template expansion: terminates in time linear in the template plus argument size; not Turing-complete; output is not fed back into the expander, ruling out unbounded re-expansion.
Epidemic dialect propagation: gossip-based with Demers et al.’s O(log n) convergence bound; agents independently verify R1–R3 and signatures before installing.
Canonical serialization per RFC 9804 for cryptographic operations — deterministic byte representation as a precondition for signature verification.
Dialect identity by content hash: name collisions resolved by canonical-form hash; downgrade attacks rejected at installation.
Self-expression vs self-adaptation (Zambonelli et al.): traditional ACLs support only parameter tuning within fixed structure; CBCL is a self-expressive protocol whose vocabulary structurally evolves under safety constraints.
Singh-aligned reading of dialect installation: a public commitment to declared semantics, with :examples clauses providing machine-checkable behavioural anchors — semantic divergence as observable breach rather than hidden mental-state mismatch.
Stated limitations: DCFL ceiling means no recursive transformations, no cross-field references (e.g. checksums over fields), no aggregation over variable-length collections, no context-sensitive validation. Standish-taxonomy paraphrastic only — no Orthophrase, no Metaphrase. Trust infrastructure (key distribution, revocation) and dialect-curation policy left to deployment.
Structural-contracts extension (sketched in §VII-D, shipped post-paper as R4 + R5): Ed25519-style dialect signatures plus protocol constraints as causal Merkle DAGs over performative-typed messages, with Visibly Pushdown Languages for shape constraints and coordination-free monotonic verification over an append-only store. Lean-mechanised lattice-homomorphism theorems (verify_monotone, verify_all_is_meet, verify_eventually_consistent) establish that replica verdicts join under G-Set merge.

Connections

Common Business Communication Language — McCarthy’s 1975/1982 origin; CBCL is the formally-verified realisation of that vision.
Security Applications Of Formal Language Theory — Sassaman et al.’s LangSec foundations.
Proof-Carrying Code - Necula — Necula 1997, the architectural ancestor of CBCL’s R4 split (host runs a small certified verifier; producer ships the proof).
Enforceable Security Policies - Schneider — Schneider 2000, the formal warrant for R5 monotone-verdict trace monitoring.
An Axiomatic Basis for Computer Programming - Hoare — Hoare 1969, root of the contract-based verification line CBCL inherits.
Authentication in Distributed Systems - Lampson Abadi Burrows Wobber — Lampson et al. 1992, the Speaks-For Calculus for delegated commitments.
Articulating Reasons - Brandom — Brandom 2000, the philosophical underwriting of Public Semantics (entry point).
Making It Explicit - Brandom — Brandom 1994, the full inferentialist treatise.
Empiricism and the Philosophy of Mind - Sellars — Sellars 1956, the Myth of the Given that makes Semantics-Without-Minds possible.
Philosophical Investigations - Wittgenstein — Wittgenstein 1953, Meaning As Use / language-games / rule-following.
Two Dogmas of Empiricism - Quine — Quine 1951, Semantic Holism.
Assertion - Stalnaker — Stalnaker 1978, Common Ground update semantics — operational analogue of CBCL’s verdict ledger.
Languages and Language - Lewis — Lewis 1975, Convention of Truthfulness picture of how an abstract language gets in force in a population.
Communicative Actions for Artificial Agents - Cohen Levesque — Cohen & Levesque 1995, the Mentalistic Semantics high-water mark CBCL deliberately is not.
FIPA-ACL Specifications — the engineering of FIPA-ACL (envelope, conversation-id, ontology slot) CBCL inherits; the semantics it replaces.
An Ontology for Commitments in Multiagent Systems - Singh — Singh 1999, the formal commitment ontology CBCL’s dialect contracts instantiate.
Jones-Sergot Normative Systems — Jones & Sergot 1993, the Counts-As Relation that gives wire events institutional meaning under a dialect contract.
Exploit Programming - From Buffer Overflows To Weird Machines — weird-machine analysis CBCL is designed to preclude at the parser layer.
PKI Layer Cake - Kaminsky Patterson Sassaman — concrete parser-differential attacks; CBCL’s class-level unambiguity rules these out at the grammar level.
The Halting Problems of Network Stack Insecurity
A Language-Based Approach To Prevent DDoS
LangSec
KQML as an Agent Communication Language
KQML - A Language And Protocol For Knowledge And Information Exchange
FIPA-ACL
ACL Rethinking Principles — Singh’s social-agency critique that CBCL’s “dialect installation as public commitment” inherits.
Agent Communication Languages - Rethinking the Principles
Verifiable Semantics for ACLs
A Common Ontology Of ACLs
Commitment-based Semantics
The State of the Art in Agent Communication Languages
Trends in Agent Communication Language
Toward Principles for the Design of Ontologies Used for Knowledge Sharing — Gruber’s ontological-commitment principle CBCL inherits.
Some Philosophical Problems from the Standpoint of Artificial Intelligence — McCarthy & Hayes’s representation/computation separation.
Elephant 2000 - A Programming Language Based on Speech Acts — McCarthy’s intra-program speech-act counterpart to CBCL’s inter-organisational vision.
Adjectival Modifiers
S-expression
Homoiconicity
Code as Data
Creating Languages in Racket — Flatt’s #lang mechanism that inspired CBCL’s homoiconic self-extension.
Extensibility in Programming Language Design - Standish
Language Extensibility Taxonomy
Paraphrase
Orthophrase
Metaphrase
Self-Expression
Self-Adaptation Self-Expression Self-Awareness ASCENS
Dialects and Idiolects
Keeping CALM - When Distributed Consistency is Easy — CALM theorem underwriting the forthcoming coordination-free contracts extension.
Visibly Pushdown Languages
MCP Landscape Security Threats And Future Research Directions
Survey Of AI Agent Protocols
Survey Of Agent Interoperability Protocols
ClawWorm Self-Propagating Attacks Across LLM Agent Ecosystems — concrete LLM-agent worm whose root-cause analysis CBCL’s lang-scoped provenance addresses.
Why AI Agents Communicate In Human Language
Why Do Multi-Agent LLM Systems Fail
Gossiping in Distributed Systems
Gossip-based Aggregation in Large Dynamic Networks

Conceptual Contribution

Claim: Agent communication languages can be simultaneously expressive, runtime-extensible, and tractably verifiable iff every message — including those that extend the language — is constrained to the deterministic context-free language class; this constraint is compatible with first-class self-extension, can be machine-checked end-to-end, and converts the unverifiable-mental-state problem of mentalistic ACLs into a public-commitment problem at the protocol layer.
Mechanism: Eight-performative core grammar (LL(1), DCFL); homoiconic dialect mechanism — dialect definitions are valid CBCL messages with extend clauses describing pattern-template substitutions; three safety invariants R1–R3 enforced at installation (no recursion via DFS cycle detection, declared resource bounds, core-vocabulary preservation); (lang name …) wrapper providing prefix-free deterministic dispatch into per-dialect sub-grammars so the union remains DCFL. Lean 4 formalization (LeanCbcl, ~5,400 LoC, 176 theorems) covering parser soundness/completeness, R1–R3, pipeline totality, and dcfl_preserved; verified parser extracted to a runnable binary (cbcl-parse). Rust reference implementation (cbcl-rs, ~11,000 LoC) with a ResourceContext-tracked single-pass expander, gossip-based dialect propagation (O(log n) per Demers et al.), canonical RFC-9804 serialization for signing, algorithm-agnostic Signer trait, C FFI / WASM bindings, property-based + differential tests, fuzz targets. Draft IETF application/cbcl Internet-Draft and Nostr transport binding.
Concepts introduced/used: Deterministic Context-Free Language, LangSec, Homoiconicity, S-expression, Dialects and Idiolects, Performatives, Self-Expression, Paraphrase, Orthophrase, Metaphrase, Visibly Pushdown Languages, CALM Theorem, Commitment-based Semantics, Public Semantics, Verifiable Semantics, Adjectival Modifiers, Ontological Commitment, Lean 4, Property-Based Testing, Parser Differential Attack, Weird Machine, Gossip Protocols, Canonical Serialization, Nostr, hence
Stance: engineering / formal-methods, with explicit position-taking on the agent-communication design space
Relates to: Realises McCarthy’s Common Business Communication Language vision (1975/1982) by giving formal safety guarantees McCarthy could only gesture at. Sits squarely in the LangSec programme of Security Applications Of Formal Language Theory and Exploit Programming - From Buffer Overflows To Weird Machines, extending it from input-validation analysis to protocol design — claiming, plausibly, to be the first ACL designed from LangSec principles and the first to demonstrate that LangSec is compatible with runtime self-extension. Inherits the DCFL-vs-ambiguous-CFG argument from PKI Layer Cake - Kaminsky Patterson Sassaman and applies it at the message layer rather than the certificate layer. Builds explicitly on Singh’s social-agency critique (ACL Rethinking Principles) and Wooldridge’s verifiability programme (Verifiable Semantics for ACLs) by treating dialect installation as a public commitment whose semantics are anchored by the :examples clause — a machine-checkable analogue of the commitment-trace conformance that Flexible Protocol Specification and Execution (Yolum & Singh) and Commitment Machines - Yolum and Singh establish for protocol actions. Where Pact - A Choreographic Language for Agentic Ecosystems takes the individual-rationality fork to answer “why follow a protocol?”, CBCL takes the publicness/verifiability fork: the meaning of a message is fully determined by the formal grammar plus declared semantics, with no mental-state inference required. Inherits Gruber’s ontological-commitment architecture but replaces “out-of-band agreement” with in-protocol propose/query/teach. The extensibility design draws on Creating Languages in Racket (Flatt’s #lang) and respects the boundary set by Extensibility in Programming Language Design - Standish: paraphrastic only, deliberately excluding orthophrase/metaphrase to keep the attack surface bounded. The forthcoming structural-contracts extension uses Visibly Pushdown Languages for shape constraints and the CALM Theorem for coordination-free verification — a natural bridge to commitment-machine semantics. The LLM-agent threat-model framing (ClawWorm Self-Propagating Attacks Across LLM Agent Ecosystems, MCP Landscape Security Threats And Future Research Directions) positions CBCL as the structural alternative to MCP/JSON-RPC-with-natural-language: same extensibility, vastly tighter security envelope.

Authentication in Distributed Systems - Lampson Abadi Burrows Wobber

Authentication in Distributed Systems: Theory and Practice

Reference: Lampson, B., Abadi, M., Burrows, M., & Wobber, E. (1992). Authentication in Distributed Systems: Theory and Practice. ACM Transactions on Computer Systems (TOCS) 10(4): 265–310. November 1992. (DEC SRC Report 83, 1992.) URL (Microsoft Research) · DOI

Summary

The ABLP paper (named for Abadi–Burrows–Lampson–Plotkin’s later refinement, but originating here) introduces the speaks-for calculus: a clean formal vocabulary for distributed authentication, delegation, and who is entitled to assert what on whose behalf. The setting: a distributed system in which principals (users, processes, machines, services) send requests that must be authorised. The traditional access-control question — is this principal allowed to perform this action on this object? — presupposes a prior question the paper answers: who is the principal whose request this is? That prior question becomes hard once requests pass through delegation chains (a user logs in to a workstation, which authenticates to a file server, which calls a database service on the user’s behalf): authentication is no longer one-to-one between principal and request but a chain of compound principals.

The technical heart of the paper is the speaks-for relation A ⇒ B: principal A speaks for principal B means that any statement A makes can be treated as if B had made it. Speaks-for is reflexive, transitive, and closed under conjunction and group membership. From A ⇒ B and A says s, the system derives B says s. Compound principals are built from atomic ones via conjunction (A ∧ B says s requires both to assert s), quoting (A | B says s means A is making a statement on behalf of B, but A retains responsibility), roles (A as R is A acting in role R), and for-channel (A for K is A speaking over channel/key K). The calculus is implementable: speaks-for facts are encoded in signed certificates, the access-control matrix grants rights to principals at any level of compoundness, and authentication reduces to checking a chain of certificates.

For the agent communication and security agenda this vault tracks, the speaks-for calculus is the formal vocabulary for delegated commitments and signed credentials. When agent B accepts a commitment from a process speaking on A’s behalf, the question “did A really commit?” is answered by the speaks-for chain witnessed by the credential. The paper is the philosophical and engineering ancestor of SPKI/SDSI (Rivest–Lampson–Ellison’s capability-style PKI, which Lampson designed using the speaks-for vocabulary), DIDs and Verifiable Credentials, object-capability facets, and modern attribute-based authorisation. For CBCL, speaks-for is the natural answer to “who signed this commitment?” — the dialect contract specifies which principals may emit which verdicts under which delegation rules, and the speaks-for chain provides the proof.

Key Ideas

Principals are first-class: a principal is anything that can make a statement — users, processes, machines, services, public keys, roles, groups, conjunctions, quotations. The system reasons uniformly about all of them.
The says operator: A says s is the primitive — principal A has asserted statement s. Authentication delivers says judgements; authorisation uses them.
The speaks-for relation: A ⇒ B means everything A says, B says. Reflexive, transitive, closed under conjunction. The delegation primitive.
Compound principals: built by conjunction (A ∧ B), quoting (A | B — A speaking on behalf of B), roles (A as R), and for-channel (A for K). A workstation acting on behalf of a user over a particular key is a compound principal at the leaf of an authentication chain.
Certificates as speaks-for witnesses: a signed certificate stating K ⇒ A (this key speaks for that principal) is the wire-format proof of a speaks-for fact. Authentication is verifying a chain of such certificates.
Access control on compound principals: the access-control list grants rights to principals at any level — Alice as Admin, Workstation | Alice for K, Group(Engineers). The complex authorisation patterns of real systems become tractable.
Trusted Computing Base separation: each principal has its own TCB; speaks-for chains let one principal delegate trust to another without fully merging TCBs.
Implementable: the paper describes the Taos system (DEC SRC) implementing the calculus; the design influenced Windows NT’s authentication architecture.

Connections

Conceptual Contribution

Claim: Distributed authentication and delegation can be cleanly formalised by the speaks-for relation A ⇒ B over a rich algebra of principals (atomic, conjunction, quoting, role, for-channel) together with the says operator. Authorisation reduces to checking that the speaker’s principal-expression has been granted rights to perform the requested action.
Mechanism: Define principals as a recursive algebra (atomic, A ∧ B, A | B, A as R, A for K). Define A says s (primitive) and A ⇒ B (speaks-for, reflexive-transitive-conjunctive). Encode speaks-for facts as signed certificates; authentication chains certificates from a trusted root to the requesting principal. Access-control lists grant rights to any principal expression; the request is authorised iff the deduced speaker’s principal is on the ACL. Implement the calculus in the Taos distributed OS as a concrete proof of practicality.
Concepts introduced/used: Speaks-For Calculus, ABLP Logic, Says Operator, Compound Principal, Quoting Principal, Role Principal, Delegation, Access Control List, Trusted Computing Base.
Stance: foundational technical paper / industry-grade reference design.
Relates to: The formal vocabulary that makes SPKI/SDSI (Rivest–Lampson–Ellison) intelligible: SPKI is the speaks-for calculus packaged as a PKI. DIDs and VCs inherit the same algebraic structure. Object capabilities (Dennis–Van Horn / EROS / Miller) are a dual view of the same problem (rights attached to objects rather than chains of delegation); the Spritely / OCapN line composes both views. For agent communication, speaks-for is the natural vocabulary for delegated commitments: when an agent’s process commits on the agent’s behalf, the speaks-for chain witnesses authority. The pair with Singh 1999 is direct: commitments without authority chains are weak, and authority chains without commitments are unactionable. CBCL’s signed-verdict architecture is a speaks-for application: the dialect contract names which principals may emit which verdicts under which delegation rules. The cryptographic complement is BAN logic (1990) and Spi calculus (1997) — BAN reasons about protocol soundness, ABLP reasons about who.

Speaks-For Calculus

Lampson–Abadi–Burrows–Wobber’s (1992) formalism for distributed authentication, delegation, and who is entitled to assert what on whose behalf. The primitives are says (principal A asserts statement s, written A says s) and speaks-for (A ⇒ B — anything A says, B says). The principal algebra is rich: atomic principals (users, processes, keys), conjunction A ∧ B, quoting A | B (A speaking on behalf of B), roles A as R, and for-channel A for K. Speaks-for facts are witnessed by signed certificates; authentication is checking chains of certificates from a trusted root. Access control then grants rights to principals at any level of compoundness. The calculus is the formal vocabulary underlying SPKI/SDSI, DIDs and Verifiable Credentials, modern attribute-based authorisation, and any system that needs to reason about delegated commitment.

In this vault

Authentication in Distributed Systems - Lampson Abadi Burrows Wobber — the founding paper
A Logic of Authentication — BAN Logic (1990) for protocol-level reasoning
Spi Calculus — pi-calculus with cryptography
SPKI-SDSI — capability-style PKI built on speaks-for
Decentralized Identifiers
Capability Myths Demolished
Programming Semantics for Multiprogrammed Computations — the Object Capability dual view
The Heart of Spritely - Distributed Objects and Capability Security
An Ontology for Commitments in Multiagent Systems - Singh — delegated commitments
Distributed Security
Agent Infrastructure
CBCL - Safe Self-Extending Agent Communication — signed-verdict architecture

Jones-Sergot Normative Systems

On the Characterisation of Law and Computer Systems: The Normative Systems Perspective

Reference: Jones, A. J. I. & Sergot, M. (1993). On the Characterisation of Law and Computer Systems: The Normative Systems Perspective. In J.-J. Ch. Meyer & R. J. Wieringa (eds.), Deontic Logic in Computer Science: Normative System Specification (pp. 275–307). John Wiley & Sons. Semantic Scholar record · DEON 1991 precursor (workshop paper, more accessible) · SEP: deontic logic

Summary

Jones and Sergot’s chapter is the founding statement of the normative systems programme in AI and computer science — the move that takes computer systems (including multi-agent systems) seriously as normative artefacts whose behaviour can be analysed in the same vocabulary as legal systems. The central technical contribution is a formal account of the counts-as relation: the relation by which a brute (physical, computational) event is treated by an institution as constituting a particular institutional event. A piece of paper of certain composition, signed in certain ways, counts as a contract in the legal institution; a particular sequence of bytes on the wire, conformant to a particular protocol, counts as a binding promise in an agent society. The counts-as relation is the bridge between brute facts and institutional facts, between syntactic events and their normative significance.

The paper develops counts-as as a conditional connective ⇒s indexed by an institution s: A ⇒s B reads “in institution s, A counts as B.” The counts-as connective is not classical material implication: it is institution-relative, non-monotonic (additional facts about the institutional context may defeat the count-as), and constitutive (the count-as relation is partly what makes the institution be the institution it is). The framework lets the authors model standard legal phenomena — speech-acts that create institutional roles, signing-procedures that count as enacting law, delegation that lets an agent’s act count as another’s, and the distinction between rules that regulate existing institutional activity and rules that constitute the institutional categories themselves. The Wieringa–Meyer volume’s surrounding chapters develop deontic logics (obligation, permission, prohibition) that combine with counts-as to specify normative systems.

For CBCL and the public-semantics line, the counts-as relation is the missing institutional bridge between the wire format and the commitment-state. A CBCL dialect contract is precisely a counts-as specification: in this dialect, this byte-sequence on the wire counts as a binding commitment with these debtor / creditor / condition / context slots. Without counts-as, the move from “the agent emitted these bytes” to “the agent has incurred this commitment” is unprincipled; with counts-as, it is a well-defined institutional bridge inheriting decades of deontic-logic infrastructure. The paper is also the unification point for the broader normative MAS literature — Singh’s commitments, Fornara–Colombetti–Verdicchio’s institutional ACL, and the broader European MAS deontic tradition (Boella, van der Torre, Castelfranchi, Carmo–Jones) all sit downstream.

Key Ideas

Counts-as relation ⇒s: an institution-indexed conditional. A ⇒s B reads “in institution s, A counts as B.” The bridge between brute facts (physical, computational events) and institutional facts (contracts, commitments, roles).
Constitutive vs regulative rules: counts-as rules are constitutive — they partly define what the institution is. Regulative rules (deontic operators: obligation, permission, prohibition) presuppose the institutional categories and govern behaviour within them. The constitutive/regulative distinction goes back to Searle 1969; Jones–Sergot give it a formal home.
Non-monotonic, institution-relative, defeasible: counts-as is not classical implication. Additional facts about the institutional context (a forged signature, an invalid delegation chain) may defeat a counts-as that would otherwise hold.
Institutions as the unit of normative analysis: an institution is a coherent body of constitutive and regulative rules. Computer systems can host institutions exactly as legal systems do.
Empowerment: certain institutional roles are empowered to perform certain acts (the judge can pronounce sentence; the agent in role seller can issue invoices). Empowerment is a counts-as fact about which acts of which role-holders count as which institutional acts.
Normative-position analysis: drawing on Hohfeld’s analysis of fundamental legal conceptions (right / duty / privilege / liability / power / immunity), the paper sketches how each Hohfeldian relation is reconstructible from constitutive-and-regulative-rule analyses.
Bridge to deontic logic: combines naturally with standard deontic operators (Os “it is obligatory in s that”, Ps “it is permitted in s that”, etc.) to give a full normative-system specification language.

Connections

Conceptual Contribution

Claim: Legal systems and computer systems can be analysed in a single formal framework — the normative system — anchored by the counts-as relation, a constitutive bridge from brute facts to institutional facts. Deontic operators (obligation, permission, prohibition) then operate on the institutional categories the counts-as relation establishes.
Mechanism: Introduce the institution-indexed conditional ⇒s (counts-as in institution s), reflexive and transitive but non-monotonic and institution-relative. Distinguish constitutive rules (which establish institutional categories via counts-as) from regulative rules (which apply deontic operators within the institutional categories). Combine with standard deontic operators to specify the full normative system. Sketch how Hohfeld’s fundamental legal conceptions reduce to constitutive/regulative patterns.
Concepts introduced/used: Counts-As Relation ⇒s, Constitutive Rules, Regulative Rules, Institutional Facts, Brute Facts, Empowerment, Hohfeldian Analysis, Normative Position, Deontic Logic.
Stance: foundational technical chapter.
Relates to: The institutional bridge missing from the commitment-based semantics line — a CBCL dialect contract is a counts-as specification (this byte-sequence, in this dialect, counts as this commitment), and without counts-as the move from wire events to institutional commitments is unprincipled. Pairs directly with Singh 1999 (commitments as the normative substrate) and with Fornara, Colombetti & Verdicchio (institutional ACL semantics). The philosophical foundation is Searle 1969’s constitutive/regulative distinction and Searle 1995’s Construction of Social Reality (counts-as as social ontology); Jones–Sergot give the formal home. Compatible with Brandomian inferentialism as a layer: counts-as gives the institutional ontology, deontic scorekeeping gives the dynamics of commitment-undertaking within that ontology. The speaks-for calculus of Lampson et al. is a counts-as fragment (this credential counts as authority to assert on behalf of). For CBCL, counts-as is the formal-vocabulary answer to “what does dialect installation actually do normatively?” — install rules give wire events institutional meaning.

Articulating Reasons - Brandom

Articulating Reasons: An Introduction to Inferentialism

Reference: Brandom, R. B. (2000). Articulating Reasons: An Introduction to Inferentialism. Harvard University Press. Based on the 1998 Locke Lectures (Oxford). URL · SEP entry on inferentialism

Summary

Articulating Reasons is the compact entry point to Brandom’s inferentialist programme — a semantics without minds in which the meaning of a sentence is its role in the inferential practices of a community of speakers, rather than a mental representation of how things stand or a Tarskian truth-condition fixed by reference. Where representationalism takes reference and truth as basic and explains inference downstream, Brandom inverts the order: the basic semantic fact is which moves count as good reasons for which other moves, and reference, truth, and propositional content are explained as features of discursive practice downstream of inferential articulation. The slogan is meaning is use, descended from Wittgenstein and Sellars, but Brandom upgrades it from a regulative idea into a worked-out pragmatist semantics.

The mechanism is a deontic scorekeeping account of assertion. To assert something is to undertake a commitment and to license other speakers to attribute that commitment back; the score every speaker keeps on every other is a record of which commitments are undertaken, which are licensed, and which are incompatible. The content of a claim is then exhaustively determined by the inferential articulation of those commitment relations: what entitles you to claim it, what it entitles you to claim, what claims it is incompatible with. The book unfolds this through six lectures — Toward an Inferentialist Semantics, Action / Reason / Inference, Insights and Blindspots of Reliabilism, What Are Singular Terms?, A Social Route from Reasoning to Representing, and Objectivity and the Normative Fine Structure of Rationality — extracting the spine of the 700-page Making It Explicit in a form readable in a week. The view explicitly avoids smuggling in mentalism: there are no beliefs or intentions in the foundations, only the public, trace-checkable practice of giving and asking for reasons.

For agent communication, inferentialism is the philosophical underwriting of the public-semantics programme: it shows that you can have a full theory of meaning — not just a thin behavioural sketch — without ever quantifying over mental states. Singh’s critique of FIPA-style mentalism gestures at this; Brandom delivers the goods. The natural pairing in this vault is with CBCL and the commitment-based semantics of Singh, Fornara, and Colombetti, all of which can be read as engineering realisations of Brandom’s deontic scorekeeping at wire-format granularity.

Key Ideas

Inferentialism: meaning is fixed by inferential role — what claims entitle a speaker to make, what they exclude, what claims entitle the speaker to make them — not by reference or truth-conditions, which are explained downstream.
Deontic scorekeeping: a speaker’s discursive score is the record of which commitments they have undertaken, which entitlements they have, and which incompatibilities apply. Assertion = undertaking a commitment + licensing attribution back to oneself.
Material vs formal inference: inferences like “Pittsburgh is west of Princeton, therefore Princeton is east of Pittsburgh” are materially good — their goodness is part of the meaning of west and east, not a downstream consequence of logical form plus reference.
Logical vocabulary is expressive, not constitutive: connectives like “if … then …” let speakers make explicit, in the form of claims, inferential commitments that were previously only implicit in practice. Logic is the technology for making practices explicit, not the foundation.
Sapience vs sentience: what distinguishes language-users from thermostats is participation in the game of giving and asking for reasons. No phenomenology required.
Singular terms and objectivity from social structure: even reference and the objectivity of claims (the gap between “what we take to be correct” and “what is correct”) are recovered from the structure of perspectival scorekeeping rather than imported as primitives.
Anti-representationalist but not anti-realist: inferentialism is compatible with robust truth, reference, and a mind-independent world — it just refuses to take those as semantic ground floor.

Connections

Conceptual Contribution

Claim: A complete theory of linguistic meaning can — and should — be built from the publicly observable practice of giving and asking for reasons, with no mental states (beliefs, intentions) in the foundations. Reference and truth are downstream of inferential articulation, not upstream of it.
Mechanism: Deontic scorekeeping: every participant in discourse maintains a score on every other participant tracking which commitments they have undertaken, which entitlements they hold, and which incompatibilities are in play. The content of a sentence is exhaustively given by its inferential articulation in this scorekeeping practice — what entitles you to assert it, what asserting it entitles you to, and what asserting it is incompatible with. Logical vocabulary is a downstream expressive layer that lets implicit inferential commitments be made explicit as further claims.
Concepts introduced/used: Inferentialism, Material Inference, Deontic Scorekeeping, Discursive Practice, Commitment (Brandom), Entitlement (Brandom), Incompatibility (Brandom), Sapience vs Sentience, Expressive Role of Logic, Semantics-Without-Minds.
Stance: foundational philosophical monograph / lecture series.
Relates to: The direct philosophical underwriting of the public-semantics / commitment-based line in agent communication: Brandom shows you can have a full theory of meaning — not just a thin behavioural sketch — without invoking mental states, which is precisely what Singh needs and what Cohen and Levesque’s mentalistic ACL semantics could not deliver. CBCL and the commitment-machine tradition can be read as engineering realisations of deontic scorekeeping at wire-format granularity: a CBCL trace is a deontic score, and a dialect contract names which inferential moves are licensed. Genealogically the book is the late chapter of the Wittgenstein / Sellars / Quine line; the Myth of the Given (Sellars) is the move that lets meaning bypass preconceptual reference, and Brandom shows how far that move actually carries.

A Commitment-Based Approach to Agent Communication

Reference: Fornara, N. & Colombetti, M. (2004). Applied Artificial Intelligence 18(9–10): 853–867. DOI: 10.1080/08839510490509054. The journal article is paywalled; the open-access AAMAS-02 conference precursor — Operational Specification of a Commitment-Based Agent Communication Language (pp. 535–542) — captures the same model and is the locally archived source. Source file: fornara-colombetti-aamas02.pdf. URL

Summary

Fornara and Colombetti develop an object-oriented operational semantics for an Agent Communication Language grounded entirely in social commitments, intended for open environments populated by self-interested, heterogeneous agents who cannot be assumed to share an honest mental architecture. A Commitment is an abstract data type with fields Identifier, Debtor, Creditor, State ∈ {empty, cancelled, precommitment, conditional, active, fulfilled, violated}, Content (a temporal proposition), Condition (another temporal proposition), and Time-out. Its evolution is given by an explicit finite-state machine driven by two kinds of transitions: agent-invoked methods (mc, mp, ap, cc, cp, rp) and event-driven update rules triggered when the truth value of the content or condition resolves.

The authors’ key innovation over the Yolum-Singh treatment is the precommitment state, which models the social situation a directive speech act creates: the speaker cannot directly commit the hearer, so a request instantiates a precommitment whose debtor is the hearer; the hearer either accepts it (turning it into an active or conditional commitment), rejects it, fulfills it implicitly by performing the action, or lets the time-out elapse. This machinery yields uniform commitment-based definitions for Searle’s main illocutionary categories — assertives (inform, informIf, informRef), commissives (promise, conditionalPromise), and directives (request, conditionalRequest, accept, reject, yes/noQuestion, whQuestion) — and lets a propose act be defined compositionally as a conditional request conjoined with a conditional promise. A worked auction-style proposal protocol is given as an interaction diagram whose state contents are computed from the speech-act definitions, and whose soundness is checked by requiring that all final-state commitments be empty, fulfilled, or violated.

Key Ideas

Commitment-as-object: a commitment is an abstract data type with a state in {e, c, p, cc, a, f, v} whose dynamics are described by an explicit FSM.
Temporal proposition class: the content/condition of a commitment is a sentence + time interval + ∀/∃ mode + state, resolved by a domain “notifier” — separating what is committed from when and how its truth is observed.
Precommitment models directive speech acts: a request creates C(p, hearer, speaker, P|Q) that the hearer can accept (ap), reject (rp), implicitly fulfil (update rule 5), or let time out.
Conditional commitment with a temporal condition becomes active when the condition is satisfied and is automatically cancelled if the condition fails.
Five update rules link the truth-state of content and condition propositions to commitment-state transitions (active→fulfilled/violated, conditional→active/cancelled, precommitment→fulfilled).
Searle’s taxonomy of illocutionary acts is recovered by composition: inform, promise, request, accept/reject, yes/noQuestion, whQuestion, propose.
Soundness of an interaction protocol is checked by an interaction diagram in which every final state’s commitments are empty, fulfilled, or violated — a structural correctness criterion for negotiation protocols.
The notion of a conversational commitment (a meta-commitment to react to interlocutor speech acts) is sketched as the principled justification for the time-out field.

Connections

Conceptual Contribution

Claim: Speech-act semantics for an ACL should be specified operationally — as state-machine transitions over a public commitment data type — so that meaning is independent of any agent’s internal mental architecture, observable to third parties, and compositional across the speech-act taxonomy; in particular, the directive family requires a dedicated precommitment state because no agent can unilaterally commit another.
Mechanism: Define an abstract Commitment class with seven explicit states and a transition FSM driven by methods (mc/mp/ap/cc/cp/rp) plus five event-driven update rules that read truth-states of Temporal Proposition objects; define each Searle category by a single-line operation on commitment objects (inform := mc(a,b,P,T), request := mp(a,b,P,T), propose := conditionalRequest ∧ conditionalPromise, etc.); validate interaction protocols structurally via a state-content interaction diagram in which final-state commitments must all be empty/fulfilled/violated.
Concepts introduced/used: Commitment, Social Commitment, Precommitment, Conditional Commitment, Temporal Proposition, Commitment-Based Protocol, Commitment-based Semantics, Public Semantics, Verifiable Semantics, Speech Act Theory, Directives, Conversation Protocols, Interaction Protocols, Open Multi-Agent Systems, Conversational Commitment
Stance: formal-semantic / engineering
Relates to: Closest neighbour is Flexible Protocol Specification and Execution (Yolum & Singh, AAMAS-02) — the authors explicitly compare the two approaches: where Yolum-Singh use the Event Calculus and an abductive planner over create/discharge/cancel/release/assign/delegate, Fornara-Colombetti use an OO/FSM data type and add the precommitment apparatus to cover directives. Both belong to the social-semantics programme catalysed by ACL Rethinking Principles and formalised verifiability-style by Verifiable Semantics for ACLs; both are subsumed under the role-based unification of A Common Ontology Of ACLs. Repudiates the mentalistic line of FIPA-ACL / Intention Is Choice with Commitment for interoperable ACL semantics while keeping speech-act theory (Speech Acts - An Essay in the Philosophy of Language, A Taxonomy of Illocutionary Acts) as the organising taxonomy. The 2004 Applied AI version this entry primarily cites elaborates the AAMAS-02 model with extended treatment of negotiation protocols and the soundness-via-conversational-commitment programme that the authors’ later artificial-institutions work develops.

Tags

Flexible Protocol Specification and Execution

Flexible Protocol Specification and Execution: Applying Event Calculus Planning Using Commitments

Reference: Yolum, P. & Singh, M.P. (2002). Proceedings of the 1st International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS ’02), pp. 527–534. ACM, Bologna. Source file: yolum-singh-2002-flexible-protocol.pdf. URL

Summary

Yolum and Singh argue that finite-state-machine and Petri-net protocol formalisms over-constrain multi-agent interactions because they fix legal sequences of message tokens without regard to what those messages mean. They develop a commitment-based alternative in which each protocol action is reified as an operation on social commitments — Create, Discharge, Cancel, Release, Assign, Delegate — and the rules for how commitments evolve are formalised in a variant of the Event Calculus (Kowalski-Sergot, in Shanahan’s planner formulation). Base-level commitments C(x,y,p) and conditional commitments CC(x,y,p,q) become event-calculus fluents whose Initiates/Terminates clauses constitute the protocol specification.

The running example is the NetBill e-commerce protocol. Three reasoning postulates capture how a base-level commitment is discharged when its content holds, how a conditional commitment resolves into a base-level commitment when its precondition fires, and how CC is consumed when its consequent already holds. An abductive event-calculus planner (Shanahan) is then used to generate protocol runs from an initial state to a goal state, allowing agents to skip steps, reorder messages, or repair exceptions at runtime — provided every base-level commitment created during the run is eventually discharged. The result satisfies Singh’s three social-semantic desiderata: meaningful (content captured), verifiable (compliance checkable from public commitment trace), and declarative (specifies what each action achieves, not how to sequence actions).

Key Ideas

Commitment as fluent in event calculus: C(x,y,p) and CC(x,y,p,q) represented by the EC predicates Initiates, Terminates, HoldsAt, Happens, etc.
Six commitment operations (Create, Discharge, Cancel, Release, Assign, Delegate) compiled into Initiates/Terminates clauses.
Three postulates link content fluents to commitment fluents: discharging on content satisfaction, conditional-commitment resolution, and conditional consumption when consequent already true.
A protocol run is a sequence of Happens events; complete iff no base-level commitment is left holding — incomplete runs identify non-compliant agents.
Abductive planning (Shanahan) generates legal protocol runs from initial-state + goal-state descriptions, restoring autonomy/flexibility lost in FSM models.
Skipping steps and reordering (e.g. send-goods-before-accept) is supported because preconditions are over commitment state, not over a path through an FSM.
Permissions encoded via action preconditions; prohibitions encoded as commitments-not-to-bring-about.

Connections

Conceptual Contribution

Claim: Multi-agent protocols should be specified by the meaning of their actions — concretely, by how each action transforms the agents’ social commitments — rather than by legal token sequences; doing so simultaneously delivers meaningful, verifiable, and declarative semantics, and lets agents skip, reorder, or repair steps via runtime planning while still being held to their obligations.
Mechanism: Reify commitments as event-calculus fluents and define the six manipulation operations (Create/Discharge/Cancel/Release/Assign/Delegate) as Initiates/Terminates clauses; add three reasoning postulates governing base-level discharge and conditional-commitment resolution; use Shanahan’s abductive event-calculus planner to compute runs (sets of Happens clauses with a partial order) from initial states to goal states under the protocol’s preconditions; declare a run complete iff no base-level commitment is left holding, providing an objective compliance criterion.
Concepts introduced/used: Commitment, Conditional Commitment, Commitment-Based Protocol, Commitment-based Semantics, Event Calculus, Abductive Planning, Public Semantics, Verifiable Semantics, Conversation Protocols, Interaction Protocols, NetBill Protocol, Commitment Machines
Stance: formal-semantic / engineering
Relates to: Direct response to FSM- and Petri-net-based protocol traditions critiqued in ACL Rethinking Principles; supplies the operational machinery whose mentalistic counterpart (KQML/FIPA-SL) is shown unverifiable in Verifiable Semantics for ACLs. Companion to Singh’s social-agency programme and to the institutional-reality strand of Agent Communication And Institutional Reality. Conditional-commitment treatment derives from Colombetti’s earlier work and is contemporaneous with A Commitment-Based Approach to Agent Communication (Fornara & Colombetti AAMAS-02 / AAI-04), which gives a complementary object-oriented account of the same primitives (those authors note Yolum-Singh as the closest relative). Commitment-machine compilation to FSMs is the subject of the authors’ parallel ATAL-01 paper. Empire of mentalistic semantics from Intention Is Choice with Commitment is the foil — here intentions/persistence are not needed because the protocol semantics is exhausted by the public commitment trace.

Tags

Commitment Machines - Yolum and Singh

Commitment Machines

Reference: Yolum, P. & Singh, M.P. (2002). Intelligent Agents VIII: Agent Theories, Architectures, and Languages (ATAL-01), LNAI 2333, pp. 235–247. Springer. (A preliminary version appeared in WET-ICE 2000.) Source file: yolum-singh-2002-commitment-machines.pdf. URL

Summary

Yolum and Singh propose commitment machines (CMs) as a protocol formalism that, unlike finite-state machines or Petri nets, attaches declarative meaning to states and actions in terms of the participants’ Social Commitments. A CM is a triple ⟨M, Δ, F⟩ of a finite minimal set of meanings (formulas in a propositional language extended with a commitment operator Cₓp and a strict-implication operator ;), a set of actions ⟨a : e⟩ whose effect e is itself a meaning, and a set of consistent final meanings. Transitions are not enumerated — they are inferred from the logical consequences of applying an action’s effect to the current meaning. The running example is the NetBill Protocol, specified by atomic propositions (request, goods, pay, receipt) and abbreviations for conditional commitments (accept = C_c(goods ; pay), promiseGoods = C_m(accept ; goods), etc.); three reasoning rules govern how commitments evolve as content propositions are made true.

The paper’s central technical contribution is a compilation procedure that turns any complete CM (one whose meaning set is closed under antecedence) into a deterministic FSM that can be executed in constant space without commitment reasoning at run time. The procedure is shown sound (Theorem 2 — every realised computation is generated by the source CM) and complete (Theorem 3 — every CM-generated computation has a semantically-strongest, efficient FSM-realised counterpart from true), via a chain of lemmas about semantic superiority, efficient computations, and endpoint equivalence. Because the meanings of states are explicit, agents executing the CM directly can plan paths through the protocol that exploit opportunities (e.g. a merchant proactively quoting without a request, “try before you buy” deals) and handle exceptions, recovering autonomy that pure-token FSM/Petri-net specifications eliminate.

Key Ideas

Commitment machine ⟨M, Δ, F⟩: state space is a finite minimal set of meanings (formulas) rather than tokens; actions ⟨a : e⟩ carry effect-meanings; final states are a consistent subset of meanings.
Inferred transitions: q ⊨_⟨a:e⟩ r iff (q ∧ e) ⊢ r — transitions are derived from logical entailment, not enumerated edges.
No fixed start state: a CM has no s₀; participants may begin from any meaning whose commitments they accept (typically true).
Three reasoning rules over commitments: (1) Cₓp discharges when p holds; (2) Cₓ(p ; r) collapses to base-level Cₓr when p holds; (3) Cₓ(p ; r) ceases when r holds before p, with no new commitment.
Compilation to deterministic FSM under two restrictions: (R1) no transition mᵢ → mⱼ if mᵢ ⊢ mⱼ (no information-free moves); (R2) the target meaning must dominate all alternatives entailed by the action (forcing maximal information).
Completeness requires “complete” CMs — meaning set closed under antecedence — so that a unique strongest target meaning always exists; trivially achieved by closing under conjunction.
Soundness, completeness, determinism established as theorems over the computation abstraction (sequences of meanings interleaved with actions); computations are compared by semantic superiority and endpoint equivalence rather than literal action-sequence equality.
Flexibility recovered for free: since states encode meanings, agents can skip steps, reorder, or take unsolicited shortcuts whenever the resulting meaning is still in M and the path to a final meaning still exists.

Connections

Conceptual Contribution

Claim: Multi-agent protocols should be specified by giving states and actions declarative meaning in terms of the participants’ commitments — not by enumerating legal token sequences — and any such specification can be soundly and completely compiled to a deterministic FSM, recovering executability without forfeiting flexibility, autonomy, or the ability to handle exceptions and exploit opportunities.
Mechanism: A propositional language with a commitment operator Cₓ and strict-implication ;; meaning sets M and final-meaning sets F (consistent w.r.t. logical consequence); action effects given as meanings; transitions inferred via (q ∧ e) ⊢ r. Compilation Procedure 1 maps ⟨M, Δ, F⟩ → ⟨S=M, Σ={a}, s₀=true, Q=F, δ⟩ under the two information-monotonicity restrictions; Procedure 2 promotes a computation to its semantically strongest counterpart, Procedure 3 removes redundant self-transitions, yielding efficient semantically-strongest computations that are realised by the compiled FSM. Soundness (Thm 2), determinism (Thm 1), and completeness for complete CMs (Thm 3) are proved.
Concepts introduced/used: Commitment Machines, Commitment-Based Protocol, Commitment-based Semantics, Conditional Commitment, Social Commitment, Public Semantics, Verifiable Semantics, NetBill Protocol, Endpoint Projection (structural analogue), Conversation Protocols, Speech Act Theory
Stance: formal-semantic / engineering
Relates to: Direct precursor and structural sibling of Flexible Protocol Specification and Execution (Yolum & Singh, AAMAS-02), which lifts the same six commitment operations (Create / Discharge / Cancel / Release / Assign / Delegate) into the Event Calculus and adds an abductive planner; ATAL-01 here is the FSM-compilation half of that programme. Companion to A Commitment-Based Approach to Agent Communication (Fornara & Colombetti, AAMAS-02 / AAI-04), which gives an OO/FSM operational semantics for the same primitives plus a precommitment state for directives. Carries forward the social-agency programme of ACL Rethinking Principles (Singh 1998) and answers Wooldridge’s challenge in Verifiable Semantics for ACLs by grounding meaning in publicly-observable commitment formulas rather than agent mental state. The Discussion explicitly contrasts with Smith et al.’s joint-intention–based protocols (mental constructs vs. social constructs) — the same fork that Intention Is Choice with Commitment anchors on the mental side. Structurally a direct analogue of choreographic Endpoint Projection: both compile a globally-specified protocol artefact to a per-role executable, the CM/FSM compilation losing declarative meaning for runtime efficiency much as endpoint projection loses the global view for distributable execution. This makes ATAL-01 the load-bearing reference for the constructive synthesis suggested in the Pact - A Choreographic Language for Agentic Ecosystems entry — choreographies could carry both communication structure (Pact-side) and a CM-style commitment trace (Singh-side), with one compilation step yielding both deadlock-freedom and conformance-checkability.

Tags

ACL Rethinking Principles

Agent Communication Languages: Rethinking the Principles

Reference: Munindar P. Singh (1998). IEEE Computer, December 1998, pp. 40-47. Source file: computer-acl-98.pdf. URL

Summary

Singh surveys the state of Agent Communication Languages (ACLs) such as KQML and FIPA/Arcol, and argues that their dominant mental-agency semantics (defining communicative acts in terms of beliefs and intentions) is conceptually unsatisfying and practically untestable because we cannot read agents’ minds. He proposes a conceptual shift to social agency: ACL semantics should be grounded in a public perspective on commitments, roles, and societies, so compliance with the standard is observable and testable.

The paper maps the ACL design space along two critical dimensions — meaning (perspective, type, basis, context, coverage of communicative acts) and agent construction (design vs. execution autonomy) — and shows how both KQML and Arcol emphasize private, mental-state semantics and thus fail to enable true heterogeneous interoperation. Singh’s alternative emphasizes protocols, roles, and “society management” infrastructure as a richer public substrate for ACLs.

Key Ideas

Mental-agency ACL semantics (KQML, Arcol, early FIPA) cannot be verified without inspecting agent internals.
ACLs need a public perspective, conventional meaning, pragmatics, and full coverage of communicative act categories.
Seven categories of communicative acts: assertives, directives, commissives, permissives, prohibitives, declaratives, expressives.
Social agency replaces BDI with commitments, roles, and societies as the semantic basis.
Dialects/idiolects arise when only private perspectives are considered.

Connections

FIPA-ACL
FIPA-ACL Specifications
KQML
Speech Act Theory
Agent Communication Languages
Multi-Agent Systems
Communicative Actions for Artificial Agents - Cohen Levesque — the Mentalistic Semantics high-water mark Singh is critiquing
An Ontology for Commitments in Multiagent Systems - Singh — Singh’s own formal sequel: the four-place commitment ontology
Commitment Machines - Yolum and Singh
A Commitment-Based Approach to Agent Communication
Articulating Reasons - Brandom — the philosophical underwriting of public, commitment-based semantics
Making It Explicit - Brandom
Jones-Sergot Normative Systems — Counts-As Relation for institutional grounding of commitments
CBCL - Safe Self-Extending Agent Communication — O’Connor 2026: contemporary realisation of Singh’s social-agency programme (dialect installation as public commitment) in a Lean-verified LangSec-grounded ACL.

Conceptual Contribution

Claim: Agent Communication Language semantics must abandon mental agency (beliefs/intentions) and be grounded in a public, social perspective (commitments, roles, societies) in order to be testable and support heterogeneous interoperation.
Mechanism: Surveys KQML, Arcol, FIPA; lays out a two-dimensional design space (meaning × agent construction); shows that mental-state semantics cannot determine compliance; proposes social-agency framework using protocols, roles, and “society management” infrastructure.
Concepts introduced/used: Mentalistic Semantics, Public Semantics, Social Agency, Commitments, Communicative Acts, Verifiable Semantics, Interoperability, Dialects and Idiolects
Stance: critique / foundational
Relates to: Direct antecedent to Verifiable Semantics for ACLs (Wooldridge) which formalises the verification problem Singh names. Sharpens the critique of the mentalistic approach underlying KQML Overview and FIPA-ACL, and motivates commitment-based frameworks such as Agent Communication And Institutional Reality.

Tags

Deontic Reduction

(page does not exist)

Context (Commitment)

(page does not exist)

Condition

(page does not exist)

Creditor

(page does not exist)

Debtor

(page does not exist)

Commitment Operations

(page does not exist)

Conditional Commitment

A commitment of the form if condition Q is satisfied, then debtor x is committed to creditor y for content P — written CC(x, y, P, Q) (Yolum-Singh) or C(cc, x, y, P|Q) (Fornara-Colombetti). When Q resolves to true the conditional commitment becomes an active base-level commitment C(x, y, P); when Q resolves to false it is cancelled. Conditional commitments are the workhorse for negotiation, conditional promises, proposals, and bidding in commitment-based ACL protocols.

In this vault

Social Commitment

A commitment treated as a public, social object — owned by the dyad of debtor and creditor and observable to third parties — rather than a private mental state of an individual agent. Social commitments are the central primitive of commitment-based ACL semantics: their lifecycle (created, conditional, active, fulfilled, violated, cancelled) is what an external observer monitors to verify protocol compliance. Castelfranchi 1995 is the foundational reference; Singh, Colombetti, Yolum, and Fornara give operational accounts.

In this vault

Agent Communication And Institutional Reality

Agent Communication and Institutional Reality

Reference: Fornara, Viganò, Colombetti (2005). Agent Communication II, LNAI 3396, Springer. Source file: 978-3-540-32258-0_1.pdf. URL

Summary

Fornara, Viganò, and Colombetti propose regarding an Agent Communication Language as a set of conventions acting on a fragment of institutional reality, defined within an artificial institution. They reformulate commitment-based ACL semantics so that all commonly used communicative act types reduce to a single basic type, declarations, within a Basic Institution that regulates the lifecycle of social commitments.

Special institutions (e.g., English Auctions) extend the Basic Institution with ontological and normative elements. The approach is notable for making the semantics of speech acts publicly verifiable and independent of agents’ mental states, while retaining a uniform formal account of institutional actions and counts-as relations.

Key Ideas

ACL messages are institutional actions governed by counts-as rules.
Basic Institution manages creation/update/cancellation of social commitments.
All speech act types reducible to declarations within the institution.
Special institutions layer domain norms and ontologies on top.
English Auction given as worked example.

Connections

Conceptual Contribution

Claim: An ACL is best understood as a set of conventions operating on institutional reality; all communicative act types reduce to declarations within a Basic Institution that governs the lifecycle of social commitments.
Mechanism: Defines artificial institutions with counts-as rules; models message effects as declarations creating/updating/cancelling commitments; layers domain norms in Special Institutions (English Auction worked example).
Concepts introduced/used: Commitment-based Semantics, Institutional Reality, Counts-as Rules, Declarations, Performatives, Speech Act Theory, Public Semantics, Verifiable Semantics, Mentalistic Semantics, Ontologies, FIPA-ACL, Multi-Agent Systems
Stance: formal-semantic
Relates to: Offers the publicly-verifiable alternative to mental-state semantics of FIPA-ACL, which A Common Ontology Of ACLs then unifies via roles; grounded philosophically in Foundations Of Illocutionary Logic.

Tags

Multi-Agent Systems

Systems of multiple autonomous agents that interact, coordinate, and sometimes compete.

Foundations

Intelligent Agents Theory and Practice — Wooldridge
Multiagent Systems Sycara
Agent-Oriented Programming — Shoham

Coordination & robustness

In this vault

Counts-As Relation

Jones and Sergot’s (1993) formal connective for the relation by which a brute (physical, computational) event is treated by an institution as constituting a particular institutional event. Written A ⇒s B and read “in institution s, A counts as B.” A piece of paper of certain composition signed in certain ways counts as a contract in the legal institution; a byte-sequence on the wire conforming to a dialect contract counts as a binding commitment in an agent society. The connective is institution-relative, non-monotonic (additional context facts can defeat the count-as), and constitutive (count-as facts partly define what the institution is). Combined with deontic operators (obligation, permission, prohibition), counts-as is the formal vocabulary of normative systems. For CBCL, a dialect contract is precisely a counts-as specification: it stipulates which wire events, in this dialect, count as which institutional commitments.

In this vault

Jones-Sergot Normative Systems — the founding chapter
Constitutive Rules
Regulative Rules
Institutional Facts
Deontic Logic
An Ontology for Commitments in Multiagent Systems - Singh
Commitment-based Semantics
Speech Act Theory
How to Do Things with Words
Speech Acts - An Essay in the Philosophy of Language
Agent Communication And Institutional Reality
Convention - Lewis
Languages and Language - Lewis
Speaks-For Calculus — a counts-as fragment (this credential counts as authority to assert on behalf of)
CBCL - Safe Self-Extending Agent Communication

Deontic Scorekeeping

Brandom’s model of discursive practice: each speaker maintains a score on every other tracking which commitments that speaker has undertaken, which entitlements they hold, and which incompatibilities are in play. To assert is to undertake a commitment and license attribution back to oneself; the meaning of a sentence is exhaustively given by how its assertion changes the score. The model is the formal core of Inferentialism: it shows how an entire theory of meaning, including reference and objectivity, can be built from publicly observable normative bookkeeping with no recourse to mental states. Stalnaker’s Common Ground / Context Set update model of assertion and Hamblin-style commitment stores from formal dialectic are the two other canonical formal models of the same phenomenon.

In this vault

Articulating Reasons - Brandom
Making It Explicit - Brandom
Inferentialism
Material Inference
Semantics-Without-Minds
Assertion - Stalnaker — Common Ground update is the operational analogue
Common Ground
Fallacies - Hamblin — Commitment Store from formal dialectic
Commitment in Dialogue
An Ontology for Commitments in Multiagent Systems - Singh — ACL-side instantiation
A Commitment-Based Approach to Agent Communication
Commitment Machines - Yolum and Singh
Public Semantics
Commitment-based Semantics
CBCL - Safe Self-Extending Agent Communication

Making It Explicit - Brandom

Making It Explicit: Reasoning, Representing, and Discursive Commitment

Reference: Brandom, R. B. (1994). Making It Explicit: Reasoning, Representing, and Discursive Commitment. Harvard University Press, Cambridge MA. ~700 pp. URL (Part One PDF, author-hosted) · Internet Archive · SEP: inferentialism

Summary

Making It Explicit is Brandom’s full statement of the inferentialist programme — the long, technical book that Articulating Reasons (2000) compresses into six lectures. Where the shorter book is the entry point, MIE is the reference manual: it works out, at the level of detail required to settle objections, how the basic discursive practice of giving and asking for reasons can serve as the foundation for an entire theory of meaning — including the parts (reference, truth, objectivity, intentionality) that representationalism takes as primitive. The book unfolds in two large parts: a pragmatic part, in which Brandom develops the deontic scorekeeping model of assertion and shows how it can recover everything one wants from a notion of speech act without recourse to mental states, and a semantic part, in which the recovery of singular terms, predicates, propositional content, and ultimately the de re / de dicto distinction is carried out in scorekeeping terms.

The book’s intellectual ancestry is openly stated: Quine on semantic holism and the analytic–synthetic collapse, Sellars on the Myth of the Given and the space of reasons, and Wittgenstein on meaning as use and language-games, all metabolised through a Hegelian appreciation of the social character of normativity. The technical innovation is to take Sellars’s insight — that the difference between a parrot trained to say “that’s red” and a person saying it is not phenomenological but inferential (a person can deploy the claim in the game of reasons) — and turn it into a full-scale semantic theory. The result is the most developed semantics-without-minds in the analytic tradition: a worked-out alternative to the mentalistic picture that has dominated philosophy of language since Searle and the early Cohen–Levesque tradition in ACL design.

For the agent-communication line, MIE is the place to send sceptics. The standard worry about public-semantics / commitment-based ACL design is that it gives up on “real” meaning in exchange for trace-checkability. Brandom’s answer, in a thousand pages, is no: deontic scorekeeping is not a thin behavioural surrogate for a richer mentalistic semantics — it is the foundation from which mentalistic talk is derivable. If Brandom is right, then Singh 1998’s move from BDI semantics to social-commitment semantics is not a retreat under pressure of verifiability; it is the correct place to ground meaning, with verifiability as a downstream bonus.

Key Ideas

Deontic scorekeeping as the basic discursive practice: speakers track, for themselves and each other, commitments (claims undertaken), entitlements (claims one is licensed to undertake), and incompatibilities (pairs of commitments that cannot both be entitled). Assertion is the basic move; the score is the running ledger.
Material inference as ground floor: inferences whose goodness is part of the meaning of the constituent terms (Pittsburgh is west of Princeton ⇒ Princeton is east of Pittsburgh) are prior to formal logical inference. Logic is a downstream expressive resource.
The expressive role of logic: conditionals, negation, and other logical vocabulary serve the function of making implicit inferential commitments explicit as new claims. This is the expressive (not foundational) role of logic.
De re / de dicto and singular terms: even classically representationalist topics — quantifying in, anaphora, singular reference — are reconstructed in scorekeeping terms, without taking reference as primitive.
Sapience without sentience: the distinction between concept-mongering creatures and the rest of nature lies in participation in the game of giving and asking for reasons, not in phenomenology.
Normative pragmatism: the social practice of holding one another accountable for commitments is the unanalysed foundation. Norms are instituted by the practice of scorekeeping, not read off antecedent facts.
Anti-representationalist but not anti-realist: truth, objectivity, and a mind-independent world are recovered from the perspectival structure of scorekeeping — not given up.

Connections

Conceptual Contribution

Claim: Linguistic meaning, including reference and objectivity, can be fully reconstructed from the social practice of deontic scorekeeping — undertaking, attributing, and tracking commitments and entitlements — without taking any mental state or representational primitive as basic.
Mechanism: A two-part construction. Pragmatic part: the basic act of asserting is the undertaking of a commitment; scorekeeping practices track commitments, entitlements, and incompatibilities. Semantic part: propositional content is the inferential role of a sentence in the scorekeeping practice; singular terms, predicates, de re / de dicto, and reference are recovered from the structure of perspectival scorekeeping. Logic is an expressive resource that makes implicit inferential commitments explicit.
Concepts introduced/used: Inferentialism, Deontic Scorekeeping, Material Inference, Commitment (Brandom), Entitlement (Brandom), Incompatibility (Brandom), Expressive Role of Logic, Sapience vs Sentience, De Re vs De Dicto, Normative Pragmatism, Semantics-Without-Minds.
Stance: foundational philosophical treatise.
Relates to: The book-length statement of which Articulating Reasons is the readable extract; read MIE only when the lectures leave a question unresolved. Genealogically continues the Wittgenstein / Sellars / Quine line — Sellars’s Myth of the Given is the antecedent move; Brandom’s scorekeeping is its destination. For agent communication, MIE is the deep philosophical underwriting of the public-semantics / commitment-based programme — Singh, Fornara & Colombetti, Yolum & Singh, and ultimately CBCL can all be read as engineering instantiations of fragments of the MIE picture.

Logic and Conversation

Reference: Grice, H. P. (1975). In P. Cole & J. L. Morgan (Eds.), Syntax and Semantics, Vol. 3: Speech Acts, pp. 41–58. Academic Press. (Originally delivered as the 1967 William James Lectures at Harvard.) Source file: grice_logic_and_conversation.pdf. URL

Summary

Grice’s foundational paper introduces the theory of conversational implicature: the mechanism by which speakers convey more than they literally say. Starting from the divergences formalists find between natural-language connectives (and, or, if, not, all, some) and their formal analogues, Grice argues the divergences do not show natural language is defective; rather, they arise from principles governing rational cooperative exchange, not from logical form.

At the centre is the Cooperative Principle: “Make your conversational contribution such as is required, at the stage at which it occurs, by the accepted purpose or direction of the talk exchange in which you are engaged.” The principle decomposes into four categories of maxims — Quantity (be as informative as required, no more), Quality (try to make your contribution true), Relation (be relevant), and Manner (be perspicuous). Speakers exploit these maxims — by apparently flouting them while the Cooperative Principle remains in force — to generate conversational implicatures that the hearer can calculate. The paper distinguishes what is said from what is implicated, and conventional from conversational implicatures, establishing the framework in which pragmatics has operated ever since. Its picture of communication as rational, cooperative, defeasible inference over an idealised shared purpose became a touchstone for ACL design, HCI dialogue systems, and the pragmatics of LLM prompting.

Key Ideas

What is said vs. what is implicated.
Conventional vs. conversational implicature.
Cooperative Principle as constitutive of rational discourse.
Four maxim categories: Quantity, Quality, Relation, Manner.
Implicatures arise from (apparent) maxim-flouting under the CP.
Implicatures are calculable, cancellable, non-detachable.
Natural-language/formal-logic divergences need not reflect semantic defect.

Connections

Conceptual Contribution

Claim: Successful communication rests on a presumed Cooperative Principle and its four categories of maxims; apparent violations of the maxims, against the background of presumed cooperation, generate implicatures — inferences about speaker meaning that go beyond literal content.
Mechanism: Grice frames discourse as goal-directed rational cooperation; derives the Cooperative Principle as a rationality constraint on contributions; distinguishes its maxims by Kantian category; shows that a speaker who says p while flouting a maxim (e.g., irrelevantly, uninformatively, or obscurely) signals that a further proposition q must be inferred to restore the presumption of cooperation — q is then conversationally implicated. Implicatures are calculable from the maxims plus context, cancellable without contradiction, and non-detachable from what is said.
Concepts introduced/used: Cooperative Principle, Conversational Implicature, Conventional Implicature, Gricean Maxims, Speaker Meaning, What Is Said
Stance: philosophical/pragmatic theory
Relates to: Complements the illocutionary classification of A Taxonomy of Illocutionary Acts by supplying a theory of pragmatic enrichment; informs the semantic/pragmatic layer distinctions in Agent Communication Languages and critiques of mentalistic ACL semantics in Agent Communication Languages - Rethinking the Principles; underpins the rational-speaker assumptions implicit in prompt engineering and LLM Agents.

Tags

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.

Tags

Speech Acts - An Essay in the Philosophy of Language

Speech Acts: An Essay in the Philosophy of Language

Reference: John R. Searle (1969). Speech Acts: An Essay in the Philosophy of Language. Cambridge University Press. Source file: Searle 1969 - Speech Acts.pdf. URL

Summary

Searle’s foundational monograph gives speech-act theory its first systematic, philosophically defended treatment. Extending Austin’s How to Do Things with Words, it argues that the minimal unit of linguistic communication is neither the symbol nor the sentence but the production of the symbol in the performance of a speech act. Searle develops a constitutive-rule analysis of illocutionary acts, codifies the felicity conditions of paradigm acts (promising, referring, predicating, asserting), and uses the framework to attack the fact/value distinction, deriving “ought” from “is” via the institutional fact of promising.

The book introduces the now-canonical machinery that McCarthy’s Elephant 2000 - A Programming Language Based on Speech Acts imports as programming-language primitives: the force/content distinction F(p), propositional-content conditions, preparatory conditions, sincerity conditions, and essential conditions. It is also the direct ancestor of Foundations Of Illocutionary Logic, which formalises what Searle here develops discursively.

Key Ideas

Speech acts as the unit of meaning: producing a sentence under appropriate conditions is performing an illocutionary act; meaning reduces to a recursive theory of these acts.
Force vs. content F(p): every utterance factors into illocutionary force (assert, promise, request, …) and propositional content.
Constitutive rules: rules of the form “X counts as Y in context C” create institutional facts (promises, marriages) rather than merely regulating antecedent behaviour.
Felicity conditions for promising (canonical analysis): propositional-content, preparatory, sincerity, and essential conditions — the template every later ACL performative inherits.
Reference and predication as distinct speech acts, each with their own rules.
Institutional facts and the is/ought derivation via promising as a constitutive practice.

Connections

Elephant 2000 - A Programming Language Based on Speech Acts — McCarthy’s direct source for the speech-act vocabulary of Elephant
Foundations Of Illocutionary Logic — Searle & Vanderveken 1985, formalises the present book
Speech Act Theory
Speech Acts
Performatives
Illocutionary Force
Sincerity Conditions
Preparatory Conditions
Agent Communication And Institutional Reality
KQML
FIPA-ACL
Agent Communication Languages
Commitment-based Semantics

Conceptual Contribution

Claim: Linguistic communication is irreducibly act-theoretic: the minimal unit of meaning is the illocutionary act, analysable by constitutive rules and felicity conditions, and this analysis extends to reference, predication, and the generation of institutional facts.
Mechanism: Case studies of promising, referring, and asserting yield a recursive schema F(p) with four condition-types (propositional-content / preparatory / sincerity / essential). The schema is then redeployed to distinguish regulative from constitutive rules and to dissolve the classical is/ought problem by showing that uttering “I promise” institutionally constitutes an obligation.
Concepts introduced/used: Performatives, Illocutionary Force, Sincerity Conditions, Preparatory Conditions, Speech Act Theory, Institutional Reality, Commitment-based Semantics
Stance: foundational / philosophical
Relates to: Imported wholesale by Elephant 2000 - A Programming Language Based on Speech Acts as the philosophical basis for speech-act I/O; formalised by Foundations Of Illocutionary Logic; re-examined for multi-agent systems in Agent Communication And Institutional Reality and operationalised in KQML / FIPA-ACL performative sets. McCarthy explicitly departs from Searle by adopting a design stance on these primitives — see Abstract Performative.

Tags

How to Do Things with Words

Reference: Austin, J. L. (1962). How to Do Things with Words. The William James Lectures delivered at Harvard University in 1955. Oxford: Clarendon Press (ed. J. O. Urmson). Source file: austin-1962-how-to-do-things-with-words.pdf. Cited by Elephant 2000 - A Programming Language Based on Speech Acts (McCarthy 1989).

Summary

Austin’s posthumously edited William James Lectures are the founding text of speech-act theory. Austin begins by isolating a class of utterances - “performatives” (e.g. “I promise”, “I do”, “I name this ship”) - that do not describe or report but instead perform an action, and cannot be evaluated as true or false but only as happy or unhappy (felicitous or infelicitous). Through twelve lectures he progressively dissolves the performative/constative distinction in favour of a general theory in which every utterance performs a locutionary, illocutionary, and perlocutionary act. The taxonomy of illocutionary force (verdictives, exercitives, commissives, behabitives, expositives) directly anticipates Searle/Vanderveken’s Foundations Of Illocutionary Logic and the performative vocabulary of KQML and FIPA-ACL.

Key Ideas

Performative utterance: saying is doing. “I promise” is not a report of a promise - it is the promise.
Felicity conditions: instead of truth conditions, performatives succeed or fail by satisfying procedural, sincerity, and uptake conditions.
Locution / illocution / perlocution: three layers of every speech act - what is said, what is done in saying it, and what is achieved by saying it.
Five illocutionary classes (verdictives, exercitives, commissives, behabitives, expositives) - taxonomy later refined by Searle into five primitives.
Dissolution of the performative/constative boundary: assertion itself turns out to be a species of illocutionary act.

Connections

Conceptual Contribution

Claim: Many utterances are not descriptions that can be true or false but actions that are performed in the saying; and on closer inspection the descriptive/performative divide collapses, so every utterance is a layered act with illocutionary force.
Mechanism: Contrast between constative and performative utterances; introduction of felicity conditions (A.1-A.2, B.1-B.2, Gamma.1-Gamma.2 misfires and abuses); the tri-layer locution/illocution/perlocution analysis; provisional five-way classification of illocutionary verbs.
Concepts introduced/used: Performatives, Illocutionary Force, Felicity Conditions, Locutionary Act, Perlocutionary Act, Speech Act Theory
Stance: foundational / ordinary-language-philosophy
Relates to: Provides the raw speech-act ontology that Searle formalises in Speech Acts and that McCarthy imports in Elephant 2000 - A Programming Language Based on Speech Acts; the felicity-condition apparatus recurs under “feasibility” and “sincerity” preconditions in FIPA-ACL semantics and in Commitment-based Semantics.

Tags

#speech-acts #philosophy-of-language #foundational #austin #performatives

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

Lineage

graph TD
  A["Austin (1962)<br/>How to Do Things with Words"] --> A1[Locutionary]
  A --> A2[Illocutionary]
  A --> A3[Perlocutionary]
  A2 --> S["Searle (1969, 1975)<br/>Speech Acts · Taxonomy of Illocutionary Acts"]
  S --> S1[Assertives]
  S --> S2[Directives]
  S --> S3[Commissives]
  S --> S4[Expressives]
  S --> S5[Declarations]
  G["Grice (1975)<br/>Logic and Conversation"] -.cooperative principle.-> S
  S --> V["Searle & Vanderveken (1985)<br/>Foundations of Illocutionary Logic"]
  V --> M["McCarthy (1989)<br/>Elephant 2000"]
  V --> KQML[KQML performatives]
  V --> FIPA[FIPA-ACL performatives]
  M --> FIPA
  KQML --> ACL[[Agent Communication Languages]]
  FIPA --> ACL

Papers: How to Do Things with Words · Speech Acts - An Essay in the Philosophy of Language · A Taxonomy of Illocutionary Acts · Logic and Conversation · Foundations Of Illocutionary Logic · Elephant 2000 - A Programming Language Based on Speech Acts

Intention Is Choice with Commitment

Reference: Cohen, P.R. & Levesque, H.J. (1990). Artificial Intelligence 42(3): 213–261. Source file: cohen-levesque-intention-is-choice-with-commitment.pdf. URL

Summary

Cohen and Levesque formalise the “rational balance” that holds between an autonomous agent’s beliefs, goals, actions, and intentions. They define intention as a composite mental attitude: a persistent goal that the agent is committed to pursuing until it is achieved, known to be impossible, or no longer relevant. This yields a modal logic whose axioms capture Bratman’s three functional roles for intention — posing problems for means-end reasoning, acting as a screen of admissibility for future intentions, and prompting the agent to track (and re-try) the success of its actions.

The paper opens with the now-classic “Willie the robot” vignette (uncommitted, overcommitted, then homicidally committed), framing intention as what an agent must reason about to be both reliable and responsive. By relativising intentions to beliefs about another agent’s intentions the authors also sketch a theory of interpersonal commitment that anticipates speech-act and multi-agent communication semantics.

Key Ideas

Persistent goal (P-GOAL): a goal an agent will not drop until it is believed achieved, believed impossible, or its relevance condition fails.
Intention defined as a P-GOAL to have done an action while believing one is about to do it — closing Bratman’s gap between intending and acting intentionally.
Avoids the “side-effect problem”: agents don’t intend foreseen side-effects of their actions.
Mutual/relativised intentions as a foundation for interpersonal commitments and speech acts.
Desiderata list (beliefs, feasibility, non-futility, tracking) becomes a standard benchmark for intention logics.

Connections

Agent-Oriented Programming
Belief-Desire-Intention
BDI Logic
BDI Architecture
Joint Intentions
Commitment
Mental State
Rational Action Semantics
Speech Act Theory
Intentional Stance
Flexible Protocol Specification and Execution
A Commitment-Based Approach to Agent Communication
Communicative Actions for Artificial Agents - Cohen Levesque — the 1995 ICMAS sequel that turns the 1990 framework into an explicit speech-act / ACL semantics; direct ancestor of FIPA-ACL.
FIPA-ACL Specifications
Mentalistic Semantics
ACL Rethinking Principles — Singh’s critique of the BDI-based ACL semantics built on this foundation.

Conceptual Contribution

Claim: Intention is not a primitive mental state but a choice with commitment — a goal plus a meta-policy for when to drop it.
Mechanism: Modal logic over beliefs and goals plus a temporal operator for persistence; intention defined compositionally so its functional roles (planning, filtering, tracking) are theorems rather than axioms.
Concepts introduced/used: Persistent Goal, Commitment, Rational Balance, Mental State, Nested Beliefs, Joint Intentions.
Stance: foundational/formal.
Relates to: Shoham’s Agent-Oriented Programming cites this paper as the prime candidate for grounding AOP’s mental-state semantics; Shoham deliberately chooses a simpler obligation/commitment primitive for AGENT-0 but frames C&L as the rigorous theory AOP languages should eventually implement. The paper also underwrites FIPA-style Mentalistic Semantics and Rational Action Semantics for ACLs.

Tags

Communicative Actions for Artificial Agents - Cohen Levesque

Communicative Actions for Artificial Agents

Reference: Cohen, P. R. & Levesque, H. J. (1995). Communicative Actions for Artificial Agents. In Proceedings of the First International Conference on Multi-Agent Systems (ICMAS-95), San Francisco, June 1995, pp. 65–72. AAAI Press. Reprinted in J. M. Bradshaw (ed.), Software Agents (AAAI Press / MIT Press 1997), ch. 19. URL (AAAI PDF)

Summary

This paper is the high-water mark of mentalistic ACL semantics: the most explicit, systematic statement of the position that an agent communication act is a complex operator on the BDI states of sender and receiver, and that the semantics of an ACL performative is given by feasibility preconditions and rational effects expressed in modal logic over those mental states. Cohen and Levesque extend the Cohen–Levesque 1990 modal logic of intention into a logic of rational action in which speech acts are first-class actions whose definitions are derivable from more basic actions of attempting to bring about a state of affairs, together with assumed Gricean rationality on the part of both agents. The standard FIPA-ACL semantics in the FIPA Communicative Act Library Specification (FIPA00037) is essentially a streamlined adaptation of the Cohen–Levesque framework.

The mechanism is precise. A speech act e performed by speaker s toward hearer h has a feasibility precondition (e.g. s believes p, s believes h does not know p, s intends h to come to know p) and a rational effect (e.g. h believes p because h believes s sincerely informed). The semantics of inform, request, promise, commit, propose, and other performatives are derived by composition from the more primitive attempt: a request is an attempt to bring about that the hearer perform an action and that the hearer believe the speaker wants the action performed; an inform is an attempt to bring about that the hearer come to believe p and to know the speaker believes p; and so on. The framework is mathematically beautiful and ontologically heavy: it requires every speech act to be defined in terms of nested beliefs and intentions of speaker and hearer, often to several levels of nesting.

This is precisely why Singh 1998 writes the Rethinking critique. The Cohen–Levesque definitions are unverifiable in practice: no external observer can check that an agent believed p when it sent inform(p); the inferential web that fixes whether the agent “really” performed an inform speaks entirely about the agent’s mental state, which is exactly the inscrutable thing the protocol participants do not have access to. The paper is therefore the canonical negative example for CBCL and the commitment-based tradition: it shows what a fully worked-out mentalistic semantics looks like, and that shows why the field has had to move on. The right way to read it in 2026 is as the high statement of a coherent but unverifiable position, not as a blueprint to implement.

Key Ideas

Speech act = action on mental states: a communicative act is a complex action whose semantics is given by feasibility preconditions and rational effects expressed over the BDI states of speaker and hearer.
Attempt as the primitive: more elementary than the standard speech-act categories is the action of attempting — an agent attempts an action toward an end if and only if it performs the action with that goal and the belief that the action is the means.
Composition of performatives: standard performatives (inform, request, promise, propose, confirm, agree, refuse) are derived by composing attempt with specific mental-state preconditions and goals.
Sincerity and competence as background assumptions: the rational effects only follow if speaker and hearer are sincere (no lying) and competent (no false beliefs). When these fail, the framework’s predictions silently fail too.
Joint intentions in conversation: extends the 1990 framework with joint intentions — for conversational acts like agreement, both parties acquire a shared intention with mutual belief.
Verifiability is a known cost: the paper acknowledges that the mental-state preconditions are not externally observable; it argues this is the price of a real semantics rather than a behavioural surrogate.
Closest formal ancestor of FIPA: the FIPA-ACL CAL spec (FIPA00037) is a direct adaptation of this framework with light editorial smoothing.

Connections

Conceptual Contribution

Claim: Communicative acts can be given precise semantics by defining them as complex actions on the BDI states of sender and receiver, derived by composition from the primitive notion of attempt under shared rationality assumptions. The semantics of an ACL performative is its feasibility precondition and rational effect, expressed in modal logic over beliefs, goals, and intentions.
Mechanism: Extend the Cohen–Levesque 1990 modal logic of intention with a notion of attempt (an agent attempts an action toward an end iff it performs the action with that goal and the belief that the action serves the goal). Define each standard performative by composition: inform(s,h,p) requires s believes p, s believes h does not know p, s intends h to come to know p; the rational effect is that h comes to believe p by mutual recognition of s’s sincerity. Similar definitions for request, promise, propose, agree, refuse, with joint-intention machinery handling conversational acts.
Concepts introduced/used: Attempt (Cohen-Levesque), Feasibility Precondition, Rational Effect, Mentalistic Semantics, Joint Intentions, Sincerity Condition, Communicative Act Library.
Stance: foundational technical paper / formal-semantics manifesto.
Relates to: The closest formal ancestor of the FIPA Communicative Act Library (FIPA00037) — the FIPA spec is essentially a streamlined adaptation of this framework. It is the negative example against which the public-semantics / commitment-based line defines itself: Singh 1998 argues precisely that the BDI preconditions are unverifiable and that ACL semantics should be grounded in observable social commitments instead. Yolum & Singh 2002, Fornara & Colombetti 2004, and Singh 1999 develop the public alternative. CBCL then operationalises that alternative as a verified, trace-checkable, self-extending wire format — explicitly not what Cohen and Levesque built. The philosophical critique of mentalistic semantics runs deeper, through Sellars / Brandom / MIE — Cohen–Levesque takes mental states as pre-given semantic primitives, which is the move inferentialism rejects.

Agent Communication Languages - Rethinking the Principles

Agent Communication Languages: Rethinking the Principles

Reference: Singh, M. P. (1998). IEEE Computer (December 1998). Source file: singh-acl.pdf. URL

Summary

Singh argues that mainstream ACLs like KQML and FIPA/Arcol are built on an untenable mentalistic semantics — grounding message meaning in the sender’s beliefs and intentions — which cannot be verified from the outside and therefore cannot serve as a compliance standard. For true interoperability in heterogeneous multi-agent systems, he proposes shifting to a social agency model in which ACL semantics is defined in terms of public commitments, roles, and conventions rather than private mental states.

The paper maps the design space of ACLs along phisssspective (private/public), type of meaning (personal/conventional), basis (semantic/pragmatic), context (fixed/flexible), coverage (of communicative acts), and construction autonomy (design/execution). It motivates “societies” of agents with published protocols, where compliance becomes testable and dialects can usefully coexist. The move from mental to social semantics underpins later work on commitment-based protocols.

Key Ideas

Mentalistic ACL semantics is non-verifiables => poor basis for standards.
Social agency: commitments, roles, conventions as public meaning.
Design/execution autonomy orthogonal and both important.
Dialects are OK; idiolects are not.
Protocols as flexible specifications, not fixed FSMs.

Connections

Agent Communication Languages
FIPA-ACL
FIPA-ACL Specifications
KQML
Speech Act Theory
Commitment-based Semantics
Mentalistic Semantics
Public Semantics
Verifiable Semantics
Interaction Protocols
Conversation Policy
Multi-Agent Systems
Communicative Actions for Artificial Agents - Cohen Levesque — the mentalistic high-water mark this paper critiques
An Ontology for Commitments in Multiagent Systems - Singh — Singh’s own formal sequel: four-place commitment ontology
Articulating Reasons - Brandom — philosophical underwriting of Public Semantics
Making It Explicit - Brandom
Jones-Sergot Normative Systems — Counts-As Relation / institutional grounding
CBCL - Safe Self-Extending Agent Communication — O’Connor 2026 contemporary realisation

Conceptual Contribution

Claim: Mentalistic ACL semantics (KQML, FIPA/ARCOL) cannot ground interoperability because compliance with sincerity and belief conditions is externally unverifiable; ACLs should be rebuilt on a social semantics of public commitments, roles and conventions.
Mechanism: Singh maps the ACL design space along six axes — perspective (private/public), meaning type (personal/conventional), basis (semantic/pragmatic), context (fixed/flexible), coverage (communicative-act repertoire), and construction autonomy (design-time vs. run-time). He uses this scheme to argue that FIPA/KQML occupy an untenable region, and sketches a social-agency alternative in which agents belong to “societies” with published protocols, commitments are first-class, and dialects (but not idiolects) are tolerated.
Concepts introduced/used: Social Agency, Commitment-Based Semantics, Mentalistic Semantics, Conversation Policy, Dialect vs Idiolect, Design Autonomy, Execution Autonomy, ACL Verifiability
Stance: critique
Relates to: Directly targets the mentalistic stance of Agent-Oriented Programming, KQML as an Agent Communication Language, and FIPA-ACL; its social-semantic programme is operationalised by An Interaction-oriented Agent Framework for Open Environments (commitment-based Mercurio/JaCaMo) and cited approvingly by the surveys The State of the Art in Agent Communication Languages and Trends in Agent Communication Language.

Tags

Agent Communication Languages

A concept hub for agent communication languages (ACLs): languages whose speech acts let software agents exchange beliefs, goals, and commitments.

Canonical Languages

KQML — original knowledge-query language
FIPA-ACL — standardised successor

Surveys & Principles

The State of the Art in Agent Communication Languages
Trends in Agent Communication Language
ACL Rethinking Principles — Singh, mental vs. social semantics
Agent Communication Languages - Rethinking the Principles
A Common Ontology Of ACLs
Toward Automated Evolution of ACLs
Towards Automating the Evolution of Linguistic Competence

Semantics

Conversations & Protocols

Domain instances

Common Business Communication Language — McCarthy 1975/1982
CBCL - Safe Self-Extending Agent Communication — O’Connor 2026 (LangSec ’26): contemporary Lean-verified DCFL-bounded ACL realising McCarthy’s CBCL vision

Mentalistic Semantics

ACL semantics in which each message commits the sender’s (and sometimes receiver’s) beliefs and intentions — powerful but unverifiable from outside.

In this vault

Public Semantics

ACL semantics grounded in externally observable facts (commitments, roles, institutional state) rather than private mental state.

In this vault

ACL Rethinking Principles
Agent Communication And Institutional Reality
Commitment-based Semantics
Mentalistic Semantics
CBCL - Safe Self-Extending Agent Communication — dialect installation as a public commitment

Commitments

Social obligations between agents expressed as debtor-creditor relations over conditional propositions. They ground ACL semantics in publicly observable state rather than private mental attitudes, enabling verification and enforcement.

In this vault

Commitment-based Semantics

Approach that grounds ACL message meaning in public social commitments rather than private mental states — making conformance verifiable.

In this vault

ACL Rethinking Principles
Agent Communication Languages - Rethinking the Principles
Agent Communication And Institutional Reality
A Common Ontology Of ACLs
Public Semantics
Mentalistic Semantics
Flexible Protocol Specification and Execution
A Commitment-Based Approach to Agent Communication
CBCL - Safe Self-Extending Agent Communication — modern LangSec-grounded ACL inheriting Singh’s social-agency programme; dialect installation as public commitment

Foundations of Logic Programming - Lloyd

Foundations of Logic Programming (Chapter 1: Preliminaries)

Reference: J. W. Lloyd (1987). Springer-Verlag, Second Extended Edition. Source file: 2022-08-18 13-38-01-Lloyd.pdf. URL

Summary

The opening chapter of Lloyd’s canonical textbook on the mathematical foundations of logic programming. It introduces first-order theories, syntax (alphabets, terms, well-formed formulas, clauses, Horn clauses), interpretations and models, and Herbrand semantics as the preferred route for reasoning about logical consequence of a program.

Lloyd motivates logic programming as Kowalski’s insight that “algorithm = logic + control”: a definite program is a set of Horn clauses (the logic), and the inference strategy (SLD-resolution, search order) is the control. He distinguishes “system” languages (committed-choice, concurrent) from “application” languages (PROLOG-style), and sets up the semantic machinery — Herbrand interpretations, models, logical consequence, unsatisfiability — needed for the rest of the book.

Key Ideas

Algorithm = Logic + Control (Kowalski’s principle)
Horn clauses as the executable fragment of first-order logic
Herbrand universe and base; Herbrand interpretations suffice for clause sets
Definite programs vs normal programs (negation)
SLD-resolution as refutation procedure (developed in later chapters)

Connections

Conceptual Contribution

Claim: Logic — specifically first-order Horn-clause logic with SLD-resolution — can serve as a programming language, where a program is a set of definite clauses, a computation is resolution refutation, and the declarative semantics (Herbrand models, least fixpoint) coincides with the procedural semantics.
Mechanism: Rigorously build up first-order theories, interpretations, Herbrand interpretations/bases, unification, and the T_P fixpoint operator; prove soundness and completeness of SLD-resolution; develop negation-as-failure, the Closed World Assumption, and semantics of normal programs; treat Prolog as the canonical realisation of the Kowalski slogan “algorithm = logic + control”.
Concepts introduced/used: Logic Programming, Horn Clauses, SLD Resolution, Herbrand Universe, Unification, Negation as Failure, Fixpoint Semantics, Prolog, Closed World Assumption, First-Order Logic, Algorithm = Logic + Control
Stance: formal / foundational textbook
Relates to: Theoretical substrate for Agent-Oriented Programming, ACRE Agent Conversation Reasoning Engine, and Ensuring Trustworthy and Ethical Behaviour in Intelligent Logical Agents (all of which assume BDI agents implemented in logic-programming languages). The mentalistic-semantics side of ACLs (KQML as an Agent Communication Language, FIPA-ACL) presupposes Lloyd-style logical machinery.