*Linguistic relativity is real at the surface and bounded at the depth.* Languages carve up the world differently at the level of content: color terms, evidentiality, tense granularity, and grammatical gender are famously variable (Boroditsky 2001; Lucy 1992; Deutscher 2010), and what a language forces a speaker to specify measurably shapes habitual attention and memory. But the effect is bounded by what every language must do anyway — distinguish referent from predicate, before from after, speaker from hearer; express negation, question, command, conditional. What varies is content; what is shared is structure. Sapir and Whorf correctly identified that languages shape thought within the space the structure permits; their critics correctly identified that the shaping cannot reach the structure itself. Each position is correct at its own level.

*Translation between languages.* The structural invariants guarantee that any proposition in one language can be rendered in another — there will always be a way to refer, a way to predicate, a way to mark relations. The contingent content guarantees something is always lost in the rendering: specific concept boundaries, morphological economy, register, sound. This is why good translation is a genuine art, not a mechanical operation, and why it succeeds imperfectly by structural necessity rather than through translator failure.

*The complementary domains of language and art.* Translating a legal contract carries the propositions forward without loss; translating a poem carries the propositions but loses the sound and rhythm that constitute much of the work. Language is the right tool for content that survives paraphrase; art is the right tool for content destroyed by it. A single utterance can do both at once — poetry in any language is exactly this — but the two operations are distinct, and understanding why is understanding why some things are said and others sung.

*Mathematical and logical languages are languages with extreme constraints on the content side.* Mathematics retains every structural feature natural language has — reference (variables, constants, named objects), predication (equations, inequalities, propositions), relational marking (operators, logical connectives) — while constraining content to what is precisely and unambiguously communicable. This is why mathematics translates across human natural languages with essentially no loss: the content is fully propositional by design. Nothing about the content depends on the natural language wrapping it. The most culturally universal language humans have built is the one that strips away everything contingent, leaving only the structural skeleton propositional content requires. That skeleton is sufficient, across cultures, civilizations, and potentially species.

*Propositional content must compose and embed.* Coordination includes talking about other propositions: what someone said or believes, what would follow from what, what would be the case if some other proposition held. A language that could express atomic propositions but not embed one inside another could not carry the content self-modeling minds need to coordinate about each other's modeling. The structural requirement is therefore compositional and recursive (Frege 1892; Hauser, Chomsky, and Fitch 2002; Pinker and Jackendoff 2005; Szabó 2022), and the derivation sits upstream of debates about whether recursion is uniquely human or the defining feature of the language faculty. Wherever it is instantiated, it is instantiated because propositional coordination structurally requires it.

*Writing exchanges temporal ordering for spatial ordering and extends transmission across generations.* The three features can be instantiated in any substrate that preserves distinction, ordering, and causal transmission. Spoken language puts the ordering in time; writing puts it in space — marks on an inscribed surface that persists. Because T and S are interchangeable for carrying an ordered sequence, any language can be written, and once written its transmission chain extends across generations the speakers never meet. Law codes, scriptures, treaties, scientific results, and accumulated culture all ride on this substrate-swap. The cognitive transformations Ong, Goody, and Havelock document — abstract reasoning, historical consciousness, recursive self-criticism in literate cultures — are downstream effects of letting propositional content persist at Physicality across far more Temporality than speech alone could reach (Ong 1982; Goody 1977; Havelock 1986; DeFrancis 1989).

*Lying and the truthfulness baseline.* Reference and predication can be combined to produce propositions that do not match the features they purport to describe. This separability is what lets language carry claims about what is not yet the case, what is not present, what is hypothetical — and the same separability lets it carry claims about what is not true. But deception is parasitic on reliability. If most propositions were unreliable, there would be no reason to attend to any proposition, and the coordination medium would collapse. Functional propositional transmission therefore requires a default of truthfulness, against which deception registers as deviation. Grice's cooperative principle and Lewis's convention of truthfulness name the coordination baseline; the structural account grounds why the baseline is required rather than merely customary (Grice 1975; Lewis 1969; Sperber and Wilson 1986; Williams 2002).

*Propositional content is used not only to describe but to do.* Austin (1962) distinguished constatives from performatives — utterances that perform actions (*I promise*, *I name*, *I pronounce*, *I apologize*) rather than describing states of affairs. The structural account derives both: propositional transmission is a coordination medium, and coordination includes reporting features of the world as well as instantiating new features of the coordination itself. *I promise to X* registers a commitment in the speaker's model and is received into the hearer's as a mutual commitment — a coordination feature that did not exist before the utterance. This is why speech act theory (Austin 1962; Searle 1969; Bach and Harnish 1979) has a natural home here: the medium was never only for description, because the coordination it serves was never only about the world as it stands.

*Language is not what makes a mind conscious, but it radically extends what consciousness can model.* Consciousness was established at [§7.8](<7.8 Life.md>) as the internal aspect of self-modeling, present wherever self-modeling is — pre-linguistic infants, cats, any language-less self-modeling mind on another world. But a mind with language can model what is not present, what has not yet happened, what another mind is thinking, what would happen under conditions that have not obtained. Language externalizes the modeling capacity into a shared medium where minds can build models together that no single one could build alone. Science, mathematics, law, philosophy, and literature are precipitates of this extension. What a linguistic community can think is not the sum of what its members can think unaided; it is the sum plus everything the shared medium lets them construct in common.

*Analytic philosophy and the medium's standards.* Reference pinned, predication precise, inference tracked across propositions — syntax, operations, semantic function, and inferential role audited at the strictness the structure permits. The discipline is internal to the medium: every analytic move is made *in* language, on the same three structural features any language must have, sharpened until the medium's constraints become a method. The argument now in progress is itself an instance — the structural features the proof requires to state itself are the structural features language has, and the analytic practice auditing propositions is language being audited within itself.

Several positions in the analytic tradition of philosophy of language stand in specific relation to the account.

*Frege, Russell, Wittgenstein, and teleosemantics.* Frege (1892) and Russell (1905) made the reference-predication distinction foundational to the analysis of propositional content; the structural account inherits it and adds the derivation — reference and predication are what propositional content structurally *is*, given T, S, Φ, and self-modeling minds coordinating within the medium. Wittgenstein's (1953) private language argument receives its structural grounding here: distinguishable signs require a shared position-space, so a sign distinguishable only to one speaker is not a sign at all, since distinction is a relation across positions. Meaning-as-use (Wittgenstein 1953; Kripke 1982) and biological teleosemantics (Millikan 1984; Papineau 1987) both locate meaning in the practices and functions of using signs. The structural account grounds those practices and functions in what coordination structurally demands, rather than in contingent features of any particular community or species-history.

*The criteria question, turned on the framework's own vocabulary.* Wittgenstein's criteria challenge is not met by grounding the private-language argument; it is met only when the same criteria pressure is turned on the terms this chapter itself uses. What are the criteria of application for *shared interiority*, or for two speakers having *the same region of modal field loaded under one label*? The answer is public and behavioral, exactly as the *Investigations* demands: two speakers share a region of field to the degree that they can be brought into agreement and correction across cases — sorting the same instances together, drawing the same inferences, repairing the same misunderstandings, recognizing the same uses as mistaken. Sameness of loaded possibility-space is not an inner comparison of two private samples, which is the move PI shows to be idle; it is the convergence of two public sorting-and-correcting practices, which is the only thing that ever counted as sameness of meaning. This also fixes what disagreement with the chapter's central claim would consist in — Wittgenstein's test of whether a sentence has gone "on holiday." To deny that language is inseparable from the structure it describes is to predict a working language some community could use — referring, predicating, understood — while lacking distinguishable signs, ordering, or causal transmission. The disagreement has cash value: produce the practice, or the claim stands.

*Quine on translation indeterminacy.* Quine (1960) argued that radical translation is indeterminate even at the level of gross reference — rival translation manuals can be equally compatible with all behavioral evidence. The account accepts the content-level indeterminacy Quine's argument establishes and rejects its extension to structure. Fine-grained content (what exactly *gavagai* picks out) is Quine-indeterminate; structural features (that *gavagai* refers, that other terms predicate, that the language marks relations) are not, because those features are what having propositional content consists in. Quine was right about what translation cannot pin down and wrong if the indeterminacy is extended to the structure translation rides on. The claim that translation is always possible survives at the structural level precisely where Quine denied it at the content level.

*Searle's Chinese Room.* Searle (1980) argued that a system manipulating signs according to rules can pass for linguistic without understanding. If so, the three structural features would be sufficient for sign-manipulation but insufficient for meaning-bearing language. The account agrees with Searle's verdict and supplies the missing ingredient. Propositional transmission requires not only distinguishable signs, sequential ordering, and causal transmission, but self-modeling minds at both ends — minds for which the signs have content because they correspond to features the minds are already modeling from inside ([§7.8](<7.8 Life.md>)). A sign-manipulating system without self-modeling carries no propositional content, however well it mimics speakers who do. Searle was right that the room does not understand, and the structural account explains why: understanding requires a self-modeling interior, which the room lacks.

*Large language models, specifically.* Current systems trained on human text produce propositionally-shaped output with remarkable fluency, passing many of the surface tests linguistic competence admits of. On the structural account they sit exactly where the Chinese Room sits — they manipulate signs with distinguishable form, sequential ordering, and causal transmission, but without self-modeling interiors for the signs to have content *for*. The fluency is real; the propositional content is absent. Whether this changes as architectures change is an empirical question the account does not foreclose: if a system were built with the relevant interior, the same structural features would carry content for it as they do for any self-modeling mind. What the account rules out is the claim that fluency alone is sufficient. Something has to be modeling something from inside for signs to become language ([§7.8](<7.8 Life.md>); Bender and Koller 2020; Bender et al. 2021; Mitchell and Krakauer 2023; Chalmers 2023).

*Kripke, Davidson, Brandom, Lewis.* Kripke's (1980) causal theory of reference grounds naming in a causal chain from an initial baptism forward through a community — Physicality persisting across Temporality through a linguistic practice, and the structural account derives why naming must take that shape. Davidson's (1984) truth-conditional semantics and principle of charity follow once coordination across self-modeling minds is the frame: interpretation must assume shared structure because without it there is no translation to do. His deeper challenge — that to posit a scheme which organizes or carves an uninterpreted reality is to revive a third dogma, an unintelligible scheme-content dualism (Davidson 1974) — is met head-on by the inseparability already established: the account sets no scheme over against a content, because language's structure *is* the structure it carries, there being no other structure for it to carry. There is no uninterpreted Reality on one side and a carving framework on the other, waiting to be lined up from some vantage outside both; there is one structure, met under language from within. The dualism Davidson rightly rejects is one the account never had — what looks like a scheme answering to a content is a single structure registered in the medium that shares it. This settles the local charge about language, but Davidson's pressure has a global edge the reply must also take: the book's foundation speaks of a Reality all description answers to — the phrasing [§8.10.1](<8.10.1 What is Disputed.md>) concedes 'is exactly the kind of view that objection targets' — and an *answers-to* can look like precisely the scheme-tracking-a-content the third dogma forbids. The edge is blunted once the register of the book's realism is made explicit. What description answers to is not an uninterpreted content lying on the far side of the account, inspected from a vantage outside language and world; it is the single a posteriori datum the whole argument rests on — that change occurs, delivered with Cartesian certainty from within ([§2.2.1](<2.2.1 Change Is Actual.md>)) — together with everything the S5 lift of that datum makes constitutive ([§4.1.9](<4.1.9 Wittgensteinian Quietism.md>)). The necessity of T∧S∧Φ is therefore not a mind-independent joint the account tracks across a scheme/content gap but a constitutive truth in the register [§4.1.9](<4.1.9 Wittgensteinian Quietism.md>) owns: it states what counts as there being an act, or a reality, at all, its only alternative being ∅. A realism of that register revives no dogma, because there is no neutral content for a scheme to organize and no standpoint outside both from which to line them up — the point [§4.3.7](<4.3.7 Mathematical Universe Hypothesis.md>) presses against Tegmark's plenitude, that the account terminates inside Reality, not above it. What is discovered is discovered from within; the *answers-to* answers to what any act constitutively involves, not to a content held apart from the describing. Brandom's (1994) inferentialism locates meaning in inferential role, and coordination among self-modeling minds does require tracking propositions in their relations to other propositions — a demand the recursive, compositional structure already established meets. His sharper challenge is the modal expressivism running from Sellars: modal vocabulary, on that view, does not describe a special class of facts but makes explicit the material-inferential commitments implicit in ordinary concept-use, so that *Reality is necessarily T∧S∧Φ* would be the explicitation of an inferential rule — from change-talk one may non-optionally infer time-talk — rather than a discovered feature of the world. The account does not resist this by insisting the conditions simply run underneath; it grants the pragmatics and locates the disagreement precisely. Expressivism is right that the modal claim is not one more descriptive report ranged alongside empirical ones, and right that asserting it makes an inferential commitment explicit: from the presence of any act one may infer distinction, ordering, and persistence, and may not withhold the inference. But making-explicit and being-constitutive are not rivals here, because what the inference makes explicit is itself the constitutive structure — the rule holds, and holds non-optionally, only because its alternative is ∅ ([§2.7](<2.7 Nothing to Consider.md>), [§4.1.9](<4.1.9 Wittgensteinian Quietism.md>)). The core vocabulary can then be given exactly the inferential articulation Brandom demands: to call something an act commits one downstream to its involving distinction, ordering, and persistence — what Space, Time, and Substance respectively do — and licenses upstream the inference to those same conditions from any act whatever; to call the structure necessary is to mark that these commitments cannot be discharged, their only release being that nothing is an act at all. That is a descriptive claim earned in the constitutive register ([§4.1.9](<4.1.9 Wittgensteinian Quietism.md>)), not asserted in the special-fact register expressivism rightly deflates — the account grants Brandom the shape of concept-use and keeps its necessity, because the very commitment his articulation makes explicit is the structure the argument derives. Lewis's (1969) convention-theoretic account roots language in coordination equilibria; the structural account explains why those equilibria take T/S/Φ-shaped forms and not others.

*Universal grammar and usage-based accounts.* The Chomsky program was right that human brains come equipped with something strongly predisposing them to acquire language in the patterns languages take. The Tomasello program is right that the patterns are learnable from communicative practice given the right cognitive substrate. What neither side emphasizes enough is that the patterns are what they are because propositional transmission structurally requires them. The brain is pre-equipped for exactly what the medium demands — and that the pre-equipment evolved by natural selection on a species living in a medium with T, S, and Φ is not surprising. The structural requirement is upstream of both accounts, and neither is complete without it.

The framework specifies the structural conditions of linguistic communication; it does not decide every object-level question those conditions raise. Which theory of reference — descriptivist, causal-historical, hybrid — best captures how particular terms attach to particular things; how pragmatic inference combines with semantic content; what individuates a language from a dialect; whether a given animal system rises to propositional language or sits below it — these remain questions for linguistics, philosophy of language, and further empirical work. Naming the structure of propositional transmission is not naming every feature of any particular language that instantiates it.

The structural conditions of propositional transmission — distinguishable signs, sequential ordering, causal transmission, with reference and predication composing them — settle a long list of debates by relocating them. Linguistic relativity is real at content and bounded at structure; translation is always possible and never complete by the same separation; mathematics is the language that strips contingent content while preserving every structural feature; lying is parasitic on a truthfulness baseline coordination structurally requires; current LLMs sit in the Chinese Room not because silicon is wrong but because no interior is modeling what the signs are for; and Quine, Searle, Frege, Wittgenstein, Davidson, Brandom, Lewis, Chomsky, and Tomasello each tracked one face of the same structural requirement. What coordination among self-modeling minds structurally owes itself is taken up at [§8.12](<8.12 Morality.md>).


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← [8.10.4 What is Confirmed](<8.10.4 What is Confirmed.md>) | [8.11 Technology](<8.11 Technology.md>) →
