Reasoning Engine

The reasoning engine takes concepts/Spindle Lisp extracted by the Scanner from across the entire vault, merges it into a single theory, and computes conclusions using concepts/Defeasible Reasoning. Every conclusion carries full concepts/Provenance.

(given spindle-core-integrated)
(given four-conclusion-types)

Pipeline

Extract — the Scanner finds SPL blocks in Markdown fences and standalone .spl files
Parse — spindle-parser converts SPL text into rule objects
Provenance — source file, line number, and page name are attached to each rule and fact
Merge — all rules and facts are merged into a single vault-wide theory
Validate — check for undefined labels, duplicate definitions, broken source references
Reason — spindle-core computes conclusions using the defeasible reasoning algorithm
Annotate — each conclusion is traced back to its proof sources with grounding freshness

Conclusion types

Tag	Meaning
`+D`	Definitely provable — strict derivation, no defeating possible
`-D`	Definitely not provable
`+d`	Defeasibly provable — inferred, no active defeaters
`-d`	Defeasibly not provable — blocked or no derivation path

Theory caching

The merged theory and its conclusions are cached in .zetl/theory.json. Invalidation uses the SPL AST hash — prose-only edits don’t trigger a rebuild. See architecture/Cache and Merkle Tree.

Feature gate

The reasoning engine is compiled only when --features reason is enabled — see Feature Gates. Without it, zetl reason prints a clear error rather than failing silently.

Cross-referencing

The --with-conclusions flag on Links Command bridges the structural graph with the logical theory, showing what each linked page contributes to the vault’s conclusions.

Type	Syntax	Meaning
Fact	`(given X)`	X is unconditionally true
Strict	`(always label body head)`	If body, then head — no exceptions
Defeasible	`(normally label body head)`	If body, normally head — can be defeated
Defeater	`(except label body head)`	If body, block head — but don’t assert the opposite

Element	Provenance
Fact	File path, line number, page name
Rule	File path, line number, page name, rule label
Conclusion	Full proof tree of contributing rules and facts
Grounding	Section hash or explicit source reference (see Drift Detection)

Flag	Default	Description
`--depth N`	1	Traverse N hops (1 = direct only)
`--fuzzy`	off	Enable fuzzy page name matching via concepts/SimHash
`--context N`	0	Include N characters of surrounding text
`--with-conclusions`	off	Show SPL conclusions each linked page contributes