Semantic Authority¶

Bytes do not explain themselves.

Core Idea¶

A protocol artifact can prove that some structure was observed: an identifier, a label, a register address, a service ID, a payload length, a checksum, or a timestamp. It does not automatically prove the engineering meaning of those fields.

Semantic authority is the source that converts evidence into named meaning. It may be a DBC file, J1939DA-derived PGN/SPN definition, ARINC label table, Modbus register map, UDS DID catalog, LIN LDF, CANopen object dictionary, ARXML model, MDF channel metadata, or a validated vendor profile.

Authority Map¶

flowchart LR bytes["Observed bytes"] --> fields["Decoded fields"] fields --> authority["Semantic authority"] authority --> claim["Named engineering claim"] stale["Wrong / stale authority"] --> false["plausible false value"] fields --> stale

Artifact	Field evidence	Semantic authority
CAN frame	ID, DLC, payload	DBC, J1939, CANopen, OEM convention
ARINC 429 word	label, SDI, data, SSM	label assignment and LRU/aircraft context
Modbus RTU frame	address, function, register offset	device register map
UDS message	service, DID, response	ISO service definition plus ECU DID catalog
MDF file	samples, channels, conversions	channel metadata and capture provenance

Wrong Authority¶

Wrong authority is dangerous because it often looks successful. A decoder may output a realistic speed, pressure, altitude, or state string even when the source database belongs to a different platform or firmware version. The result is not random noise; it is a plausible false value.

Observer Rule¶

A passive observer may say:

I observed these bytes.
I decoded these fields under this framing hypothesis.
I applied this named authority.
Therefore this is a state hypothesis with this provenance.

The observer should not say:

The machine was definitely in this state.

unless the authority, timing, and provenance support that claim.

Binder Rule¶

Every semantic page must identify where meaning comes from, who defines it, what version or provenance is known, and what ambiguity remains. Pages that skip this step are not final-copy-ready.