outlist-enables-non-monotonic-reasoning
IN premise
The `outlist` field on `Justification` allows beliefs to be retracted when a defeating node becomes IN — this is the core non-monotonic mechanism powering `supersede`, `challenge`, and default-logic patterns.
Summary
When a justification includes an outlist, it means that justification only holds as long as certain other nodes stay OUT. If one of those defeating nodes becomes IN, the justification fails and the belief gets retracted automatically. This is what makes the system non-monotonic — adding new information can cause previously held conclusions to be withdrawn, which is the foundation for patterns like one belief superseding another or defaults being overridden by exceptions.
Dependents
These beliefs depend on this one:
- outlist-is-universal-defeat-mechanism — The outlist primitive is the sole defeat mechanism underlying all non-monotonic features: challenges, agent kill-switches, supersession, and direct defeasible reasoning
Details
| Source | entries/2026/04/23/reasons_lib-__init__.md |