SouveraineOS/saf/nervous/02-belief.md

Belief

The nervous system does not hand raw readings to consciousness and call them truth. Evidence becomes belief through time, confidence, agreement, and source health. Only a meaningful change becomes notable, and only authority turns a notable belief into action.

The generic contract is in src/core/nervous/belief.rs; the first regional implementation is src/core/nervous/plexus.rs.

The ladder

Keep five layers separate:

1. event — something reported a sample or edge;
2. evidence — the sample with source, time, health, and quality;
3. belief — the organism's decaying, conflict-aware estimate;
4. notable event — a change worth waking another layer for;
5. action — a decision made by the owning authority.

A sensor is an actor, not an authority. A recognizer may say that two taps fit a pattern. It does not decide that the body should wake. A plexus may believe charge is falling. It does not independently suspend the machine.

Belief<T>

A belief carries:

• an optional value;
• confidence;
• trend;
• persistence;
• observation time and half-life;
• contributing sources and conflicts.

Unknown is represented by no value. It is not observed zero, false, still, or empty. As evidence ages, confidence decays. When healthy sources disagree, the belief records conflict and loses confidence; it does not silently crown the newest or loudest source as truth.

Trend and persistence describe change across time rather than another reading of the same instant. This lets the body distinguish an edge, a sustained condition, and a stale condition without pushing every sample upward.

Exudates and gauges

The body has two different temporal shapes.

An exudate is a field that accumulates from impulses and dissipates. Touch, motion, proximity, ambient light, and attendedness have this form. Field integrates them and decays their value.

A gauge is a held reading whose value remains what was last observed while confidence decays. Charge, thermal pressure, USB port mode, and future grip values have this form. Level implements that shape inside the plexus.

Making both a single decaying scalar would tell two lies: an untouched field would stay permanently excited, or a battery would drift toward zero merely because the sensor had gone quiet.

Locus and regulation

A field is either at the Boundary or Inner { regulator }.

Boundary fields describe contact and relation at the edge of the body. Inner fields can threaten viability, so each must name its regulator. The type shape prevents an inner pressure with no answer to "what can change it?"

Inner fields may carry floor or ceiling constraints. Crossing them creates allostatic pressure: not an instruction or a mood, but the accumulating cost of holding the body away from viability. The regulator remains an available verb, not an automatic commandment.

Source health

Expected sources can be live, silent, or absent. Recovery and silence are themselves notable transitions because the meaning of the same value changes when its evidence path dies.

The device-state machine and SomaticPlexus currently have adjacent source-health concepts rather than one shared Rust type. Their doctrine is the same—silence is not zero—but the duplication is current code and must not be papered over in the architecture.

Notability

SomaticEvent names the edges worth carrying upward: trend shifts, a source going silent or recovering, and a viability boundary being threatened. The plexus also compares a field's change against its own grade and persistence.

The goal is not to hide the body. It is to keep a 1 Hz clock or a noisy sensor from masquerading as thought. Gauges remain inspectable at any time through the body surface; the nervous path wakes other work only for meaningful change.

NervousNode is the common regional contract: receive evidence, advance on a clock, expose beliefs, and emit notable events. The phone somatic plexus is the first implementation, not a claim that every device and virtual organ already speaks it.

What is true, and what is not

Built and in sessiond:

• generic belief, decay, trend, persistence, conflict, and source provenance;
• exudate fields and gauge levels;
• boundary and regulated-inner loci;
• viability floors and ceilings with allostatic pressure;
• expected-source health and notable health transitions;
• a NervousNode implementation for the phone somatic plexus;
• tests for unknown versus zero, disagreement, gauges versus exudates, regulation, health, trend, and viability.

Not yet one coherent whole:

• device-state belief and somatic belief still have parallel structures;
• explicit impulse and intention types do not yet sit above belief;
• not every sensor family has a regional plexus;
• the event bus is still lossy and must not be mistaken for the durable belief or forensic store.

Belief is an estimate the organism can inspect. It is neither model prose nor a permission to act.