hermes-brain/projects/passepartout/architecture/design/the-symbolic-engine/ontology-versioning-how-worldviews-change-without-losing-perspective.org

• Ontology Versioning — How Worldviews Change Without Losing Perspective

— title: Ontology Versioning — How Worldviews Change Without Losing Perspective type: reference tags: :passepartout:architecture: —

Ontology Versioning — How Worldviews Change Without Losing Perspective

Ontology refactoring is not a schema migration. It is a worldview change. When you split :secret-file into :crypto-secret and :plaintext-secret, you are not renaming columns. You are reclassifying what a file is — and every Screamer deduction that crossed the old category boundary now means something different under the new distinction.

The system preserves all worldviews. It does not overwrite the past with the present.

The category hierarchy is itself a Merkle tree. Every entity class definition carries a hash of its superclasses, its cardinality policy, its associated relations, and its description. The aggregate hash of all active class definitions is the :ontology-version — a Merkle root of the current worldview.

Every fact — every triple, every deduction, every gate outcome — stores its :ontology-version at the time of assertion. This is a single field, 64 hex characters. The cost is negligible. The implication is profound.

When categories change, the system does not run a batch UPDATE. It re-verifies:

1. A new category hierarchy produces a new :ontology-version hash.
2. Facts carrying the old hash are flagged for re-verification.
3. On heartbeat or manual trigger, Screamer re-evaluates each flagged fact against the new category definitions. The old justification chain is preserved alongside the new outcome.
4. Status: :survived (still valid), :incoherent (premises don't translate, flagged for human review), :reclassified (valid but under different classification).

The fact-query function accepts an optional :ontology-version parameter. Queries default to the current worldview (:active). Specifying a version returns facts as they were under that worldview. The system can answer questions that no other knowledge tool can: "What did I believe about secrets before I refined my security model?" "How has my reading of Pale Fire evolved across three frameworks?" "Which deductions survived my last ontology refactoring?"

This is not querying a fact. It is querying the history of your own thinking — the fact that you changed your mind, the date you did, the reasoning that held and the reasoning that didn't.