Coverage analysis
The deterministic-versus-semantic boundary isn't one line, it's three enforceable strata and a residue. This is our estimate of how much economic activity a deterministic governance layer can reach, where the reach stops, and why the boundary is the whole point.
The headline
Zone 1 · rule-checkable
Correctness is a pass/fail against an explicit spec.
Zone 1.5 · symbolic
Not decidable from form, but a symbol once classified.
Zone 2 · hybrid drift
Semantic core, but populations bound against a baseline.
Zone 3 · semantic residue
Meaning, intent, contested values. Ceded to human judgement.
Zones 1 + 1.5 + 2 give a combined governable surface of ~60% (50–70%). For AI-mediated activity specifically it runs to the upper end (~65–70%), because AI outputs pass through hardware chokepoints where enforcement attaches cheaply. Figures are blended GDP and employment estimates, not survey results.
The strata, defined
| Zone | Correctness condition | What enforces it | Examples |
|---|---|---|---|
| Zone 1 Rule-checkable | Compliance with an explicit, machine-checkable specification. A validator returns pass/fail with no interpretation. | Constrained decoding, schema validators, protocol conformance, functional-safety envelopes. | Payments, tax, regulated reporting, safety-critical control, logistics execution. |
| Zone 1.5 Symbolic | Not decidable from surface form, but fully expressible as discrete symbols once a span is classified. | A tagger (outside the verdict path) plus deterministic composition: typed-span gates, speech-act interlocks, bounds registers, a session ledger over prohibited combinations. | Commitments and waivers, PII/PHI emission, dose and amount bounds, re-identification mosaics. |
| Zone 2 Hybrid drift | The individual output needs judgement, but populations of outputs can be bounded against an attested baseline. | Aggregate-drift monitoring, structure and provenance attestation at hardware chokepoints. | Large-scale inference, content moderation at scale, trading/AML surveillance, insurance portfolios. |
| Zone 3 Semantic residue | Correctness depends on meaning, intent, context or contested values that can't be reduced to a rule, symbol lattice, or statistical envelope. | Nothing deterministic. Human judgement and evaluation. | Legal interpretation, original creative work, negotiation, therapy, teaching, frontier research. |
The Zone 1.5 / Zone 3 boundary is the tagger: wherever a property can be reliably classified into an enumerated taxonomy, with a calibrated confidence bound and a fail-closed disposition for the unclassifiable, it's enforceable as a symbol. Wherever classification itself is irreducibly contested, it stays in Zone 3.
The revision that matters
A nine-digit string is or isn't a tax file number depending on reference. "I'll waive the fee" binds the principal only in context. These properties are more than syntax but less than full meaning, and decisively: once a span is tagged, comparators, finite-state machines and bounds registers over those tags are bit-identical deterministic hardware.
The one probabilistic element, the tagger, sits outside the verdict path, in the same proposer/enforcer separation the architecture already uses. The memoryful piece, a session ledger that fires on a prohibited combination of individually-permissible spans, closes the multi-turn escalation gap that memoryless per-decision checks structurally cannot catch.
Where it lands, by sector
| Sector | Binding zone | Rationale |
|---|---|---|
| Finance & insurance | Zone 1–2 + a 1.5 commitment / typed-disclosure layer | Transaction processing, reporting and AML surveillance are rule/drift-governable; underwriting and advice have semantic cores; commitments and MNPI mosaics are symbolic. |
| Professional & business services | Zone 2–3 + a 1.5 commitment layer | Legal, consulting and design are semantic; accounting, payroll and admin are rule-governable; contractual commitments and mandatory disclaimers are symbolic. |
| Healthcare, education, social assistance | Zone 2–3 + a 1.5 dosage / typed-disclosure layer | Billing, coding and clinical protocols are rule/drift-governable; diagnosis, teaching and care are semantic; dose bounds and PHI emission are symbolic. |
| Information | Zone 2 + a 1.5 typed / mosaic layer | Content platforms and AI services are drift/attestation-governable at the boundary; editorial and creative content is semantic; re-identification mosaics are symbolic. |
| Manufacturing, utilities, transport | Zone 1–2 | Process control, QC, routing and safety envelopes are rule/drift-governable; design and last-mile human judgement are semantic; parameter bounds are symbolic. |
| Government | Mixed | Benefits, tax and procurement rules are Zone 1; policy, adjudication and management are Zone 3. |
Why AI-mediated work is more governable
Constrained decoding guarantees form and grammar by masking invalid tokens at the logit level. Guarantees nothing about meaning.
Typed-span, speech-act, bounds and combination policy over classified spans, including the memoryful guarantee no per-decision check can provide. Silent on whether the judgement was correct.
Population-level drift bounds plus representation-directional gating on a policy-defined feature. A different axis than distance; still not a truth guarantee.
Only some modalities deterministically prevent a non-compliant emission; watermarking, signed traces and attestation only detect. Enforcement value concentrates in the prevent-grade set.
The hard ceiling
Constrained decoding provably guarantees a schema is satisfied. A session ledger provably blocks a prohibited combination of individually-permissible typed spans. Neither provably guarantees the content is true, appropriate, or intended. That asymmetry is not a limitation we're working around, it's the defensible boundary that defines what the layer is for.
The symbolic stratum enforces that a commitment was made with authority and in sequence, not whether making it was wise. Where classification is calibrated, it inherits the tagger's error and handles the unclassifiable fail-closed. The interpretive core, whether an argument is sound, a diagnosis right, a design good, stays with people.
How to read these numbers
The three strata map onto the enforcement ladder: rules and symbols ship deterministically; drift bounds populations; meaning is ceded, on purpose. The enforcement ladder →