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

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.

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

Languages and Language - Lewis

Languages and Language

Reference: Lewis, D. K. (1975). Languages and Language. In K. Gunderson (ed.), Language, Mind, and Knowledge (Minnesota Studies in the Philosophy of Science, vol. 7, pp. 3–35). University of Minnesota Press. Reprinted in Philosophical Papers Volume I (Oxford UP 1983). URL (Minnesota Digital Conservancy)

Summary

“Languages and Language” is Lewis’s mature statement of the distinction between a language (an abstract function from sound-and-sign types to meanings, with no users) and language (a social phenomenon: a population’s practice of using a particular abstract language to communicate). The paper sharpens the framework introduced in Convention (1969) and rebuts an objection from Strawson and Searle that an account of language as convention — solving a coordination problem by mutual expectation — misses the normative heart of meaning. Lewis answers: it does not. A population uses an abstract language L iff there prevails in that population a convention of truthfulness and trust in L — a regularity by which speakers utter sentences of L only when they believe them true-in-L, and hearers respond by coming to believe the sentences uttered are true-in-L. The regularity is a convention in the technical Lewis 1969 sense: it solves a coordination problem (mutual intelligibility), it is sustained by mutual expectation (common knowledge that it is so sustained), and it has alternatives (some other abstract language could have played the same role).

The paper’s value over Convention is its precise account of the language–language relation. The abstract object L is a function from finite strings to truth-conditions (or, for non-declarative moods, to satisfaction-conditions). The social object — language — is the convention of truthfulness and trust in L. Different populations use different Ls; the same population can use several Ls for different domains. Meaning is not primarily a property of individual speakers’ minds: it is a property of the convention, fixed once we identify which L the population’s convention picks out. Speakers’ beliefs and intentions enter only via the convention-sustaining clauses (each speaker expects the others to be truthful-in-L and tries to be so themselves), not as the bearers of meaning.

For agent communication, “Languages and Language” is the cleanest philosophical statement of the public-semantics programme avant la lettre. The meaning of a wire-format performative is not the BDI state of the sender or receiver; it is the truth- or satisfaction-conditions assigned by the abstract language the protocol convention picks out. Two agents using FIPA-ACL are participating in a convention of truthfulness and trust in the abstract language defined by FIPA-ACL’s semantics. The convention requires only that agents act as if truthful-in-L; it does not require introspective access. This is exactly the dialect-and-protocol picture that Singh 1998 argues for, that commitment machines formalise, and that CBCL turns into a verified, self-extending wire format. Lewis 1975 is also the philosophical complement to Convention: where the 1969 book establishes the game-theoretic apparatus, the 1975 paper applies it to language and shows how to answer the standard objections from the speech-act tradition.

Key Ideas

Two senses of “language”: an abstract language L is a function from sentence-types to meanings (truth- and satisfaction-conditions); language (no article) is the social phenomenon — a population’s use of some L. Confusing the two is the source of much philosophy of language.
Convention of truthfulness and trust: a population uses L iff it has a convention (in the 1969 sense) of truthfulness in L (utter sentences only when believed true-in-L) and trust in L (hearers respond to such utterances by coming to believe the sentences true-in-L).
Meaning is a property of the convention, not the speaker: the convention picks out which L is in force; the meaning of a sentence in that population’s language is its meaning in L. Individual speaker mental states enter only as the conformity conditions of the convention.
Coordination problems and alternative languages: many abstract Ls could solve the population’s coordination problem; salience, precedent, and history pick one. Meaning is not arbitrary in function but contingent in particulars.
Reply to Strawson/Searle: the objection that convention-based accounts cannot capture the normative dimension of meaning is misplaced — the convention is itself a normative structure (it requires mutual expectation and conformity to be in force).
Multiple languages, one population: a population may use several Ls simultaneously — formal and informal registers, technical sub-languages, jargon — each sustained by its own convention.
Sentence moods and non-declaratives: imperatives and interrogatives are handled by extending the abstract L to assign satisfaction- and answerhood-conditions; the convention-of-truthfulness-and-trust generalises to a convention of acting as if the satisfaction-conditions held.

Connections

Conceptual Contribution

Claim: Sharpen the Convention 1969 picture into a precise account of how an abstract language L (a function from sentences to truth-/satisfaction-conditions) gets in force in a population: by a convention of truthfulness and trust in L. Meaning is a property of the convention, not of individual speakers’ mental states.
Mechanism: Define abstract languages as functions from sentence-types to truth- and satisfaction-conditions. Define use of L by population P as the prevalence in P of a convention (in the Lewis 1969 sense) of being truthful in L and trusting in L. Show how this answers Strawson’s and Searle’s normativity objection (the convention is itself normative) and how it generalises to non-declarative moods (satisfaction-conditions) and to populations using multiple Ls.
Concepts introduced/used: Abstract Language, Convention of Truthfulness, Convention of Trust, Truthfulness and Trust, Sentence Mood, Pragmatic Presupposition, Public Semantics.
Stance: foundational philosophical paper.
Relates to: Direct sequel to Lewis 1969 (Convention) — the 1969 book gives the game-theoretic foundations, the 1975 paper applies them to language. Operational complement to Stalnaker 1978: where Stalnaker gives the update mechanics of assertion, Lewis 1975 says what makes a particular abstract language the one the participants are updating in. For agent communication, this is the cleanest philosophical statement of the public-semantics programme: the meaning of an ACL performative is fixed by the protocol convention’s chosen L, not by speakers’ BDI states — exactly the picture Singh 1998 argues for, commitment machines formalise, and CBCL turns into a verified wire format. The view also locates Wittgensteinian meaning-as-use within an explicit game-theoretic setting (Lewis’s convention is the formal regulariser of Wittgenstein’s language-games), and is compatible with Brandomian inferentialism as a downstream layer (inferential articulation is what gives L its truth-conditions in the first place).

Convention - Lewis

Convention: A Philosophical Study

Reference: Lewis, D. K. (1969). Convention: A Philosophical Study. Harvard University Press, Cambridge MA. (Reprinted 2002, Blackwell.) SEP entry on Convention · Wiley publisher page (book; no full-text OA.)

Summary

Lewis offers the first rigorous game-theoretic analysis of how shared conventions — including, paradigmatically, the conventions of language — arise and sustain themselves among rational agents without explicit agreement. The book opens by defining a coordination problem: a situation in which several agents have multiple equilibria available, all parties prefer reaching some equilibrium to none, and they are largely indifferent (or have non-conflicting preferences) over which equilibrium they reach. Lewis’s central thesis is that a convention is a regularity in behaviour that is one solution to a coordination problem, sustained by mutual expectation — each party expects the others to follow the regularity, expects the others to expect them to follow it, and so on up an infinite hierarchy that Lewis was the first to formalise as common knowledge. The book applies this analysis to driving conventions (drive on the right vs left), signalling, currency, and at length to language: the conventions of meaning are coordination equilibria sustained by mutual expectation in a population of speakers; semantic content is what would be the case if the convention were followed. Lewis’s framework supplies the philosophical foundation for every later treatment of emergent and negotiated meaning — emergent-communication research in MAS and deep learning, the ACL evolution programme, and the language-games tradition (Wittgenstein operationally, Steels formally) all proceed in the conceptual space Lewis defined. The common-knowledge construction is independently a foundational result for distributed-systems theory (Halpern & Moses 1990) and game theory (Aumann 1976).

Key Ideas

Coordination problem: a strategic situation with multiple Pareto-comparable equilibria where no party prefers a non-equilibrium outcome and the parties’ preferences over equilibria largely coincide. The classical examples — driving side, meeting place — generalise to language, money, social roles.
Convention as a self-sustaining regularity: a regularity R is a convention iff (i) almost everyone conforms to R, (ii) almost everyone expects almost everyone else to conform to R, (iii) almost everyone prefers conforming on the assumption that others conform, and (iv) some alternative regularity could have been the convention instead (no party of the convention is intrinsically preferred).
Common knowledge: the infinite hierarchy of mutual expectation that sustains a convention — A knows that B follows R; A knows that B knows that A follows R; and so on. Lewis was the first to give a formal account of this in social terms; the construction was rediscovered by Aumann in game theory and Halpern–Moses in distributed systems.
Salience and precedent as convention selectors: when multiple equilibria are available, salient features (Schelling’s focal points, see The Strategy of Conflict) and historical precedent select among them. There is no rationality-driven argument for which equilibrium becomes conventional; the answer is contingent on saliency.
Language as convention: meaning is what would obtain if the convention were followed. Truth-conditions, communicative force, and reference are all conventionally fixed — but the convention is not arbitrary, it is sustained by everyone’s expectation that everyone else will use words a particular way.
Conventions vs explicit agreements: Lewis argues that explicit agreement is neither necessary nor sufficient for convention — many conventions arise without agreement (precedent does the work) and many agreements never become conventions (because mutual expectation does not develop).
Population vs pair: conventions are population-level facts; one cannot have a convention with a single partner. Mutual expectation must extend across the relevant community for the regularity to be convention-grade.

Connections

Conceptual Contribution

Claim: Conventions — including the conventions of language — are best analysed as solutions to coordination problems sustained by mutual expectation (formally, common knowledge) in a population of rational agents. There is nothing arbitrary about the convention’s function, but the particular regularity that becomes conventional is contingent on salience, precedent, and historical accident.
Mechanism: Game-theoretic analysis of coordination problems with multiple equilibria; definition of convention via four clauses (conformity, mutual expectation, conditional preference, alternativeness); explicit construction of common knowledge as an infinite hierarchy of expectations; application to driving conventions, signalling, currency, and at length to language semantics.
Concepts introduced/used: Coordination Game, Convention (Lewis), Common Knowledge (Convention), Mutual Expectation, Focal Point (via dialogue with Schelling), Salience, Precedent, Convention vs Agreement.
Stance: foundational philosophical monograph.
Relates to: Direct philosophical foundation for every later treatment of emergent meaning and negotiated language: Steels’ language games are operational realisations of Lewis’s coordination-problem analysis with explicit interaction protocols; Lazaridou et al. and the deep-learning emergent-communication line train neural agents to converge on Lewis-style conventions in referential games. The ACL-evolution programme (Toward Automated Evolution of ACLs, Towards Automating the Evolution of Linguistic Competence) treats the ACL itself as an evolving Lewis-convention. Lewis’s common-knowledge construction is independently the foundation of Halpern & Moses 1990 in distributed systems and Aumann (1976) in game theory — distributed protocols and conventional language share the same mathematical object. The framework also clarifies what is at stake in the Mentalistic Semantics vs Public Semantics debate in ACLs: Lewis-style conventions are public-semantics objects (mutual-expectation regularities) but their stability depends on something close to mentalistic conditions (each agent’s expectations about others’ beliefs), so the two semantic families are dual aspects of the same phenomenon rather than competitors. Why AI Agents Communicate In Human Language revisits Lewis from the LLM-agent angle: natural language is a particular Lewis-convention (a contingent equilibrium) and not necessarily the optimal one for inter-agent coordination.

Tags

#convention #coordination #common-knowledge #lewis #philosophy-of-language #foundations #emergent-meaning

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

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

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

An Ontology for Commitments in Multiagent Systems - Singh

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.

Deontic Logic

Modal logic of obligation, permission, and prohibition — formal basis for reasoning about norms and ought-to-be in agent systems.

In this vault

Institutional Facts

Searle’s category: facts that exist only because we collectively accept them (money, marriage, property), generated by constitutive “counts-as” rules. Foil to brute facts and a touchstone for Agent Communication And Institutional Reality.

In this vault

Regulative Rules

Searlean rules that regulate already-existing behaviour by permitting, obliging, or forbidding actions; in Mercurio they layer over constitutive rules to govern legal interaction sequences in open MAS.

In this vault

Constitutive Rules

Searle’s rules of the form “X counts as Y in context C” that create new institutional facts rather than merely regulating pre-existing behaviour. In agent frameworks they link brute message events to social meanings such as commitments or role assignments.

In this vault

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.