nolang

A small language where uncertainty is a value, and confidence decides what an agent is allowed to do.

Early, but real: a working reference implementation, a published theory, and the design in the open. Grown on a NARS substrate, not written from scratch.

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Why a language, and not a library

A library can add a confidence score to a call. It cannot change what the surrounding code is allowed to do with that score, because control flow in every mainstream language is boolean: a branch takes yes or no, a tool call takes a value. There is no place to put "I don't know", so uncertainty is rounded to a guess and the guess acts.

nolang makes that missing place part of the language.

The core idea

Two kinds of thing, kept apart:

• values — a path, a string, a binding. Plain. No truth attached.
• judgments — (isa tomato vegetable). These carry a pair (frequency, confidence): how far it holds, and how sure we are.

Computation is (value-or-judgment, trace): a graded-truth-and-provenance result. Confidence is not decoration. It governs which class of action is permitted:

(if (check (isa migration safe))
    (return :apply)        ; confident   -> irreversible move allowed
    (observe migration))   ; not sure    -> reversible move only; snapshot first

The if is three-valued: confident-yes, confident-no, and undecided. The third branch does not guess and does not discard. It routes the question to a check that looks a different way.

The weak, useful requirement: to gate an action, confidence need not be accurate, only monotonic — "more sure" must outrank "less sure". This is why the gate works on models known to be badly calibrated.

Lineage

Not invented in a vacuum. nolang stands in a line:

• McCarthy — Lisp; the Advice Taker, programs that reason.
• Pei Wang / NARS — reasoning under insufficient knowledge and resources; the (f, c) substrate.
• Prolog — resolution as a semantic thesis, not a syntax.
• Unix — bounded, honest I/O.

nolang is homoiconic (a Lisp), targets the runtime of a single agent, and hands hard reasoning down to a real substrate (NARS / Prolog) rather than pretending to do it itself.

Return is a primitive: ilan

Low confidence is only safe if there is a way back. In nolang, the way back is a language primitive, not a convention. That primitive is ilan: fold collapses live state into a seed; sprout grows it back, still remembering the crossing. An agent that acts under low confidence folds first, and can return — not to a blank slate, but to itself with the memory that it went. Return without that memory is amnesia, not freedom.

Run it

A working reference implementation in Common Lisp (SBCL). Eight small stones — atom, gate, return/ilan, eval, types, world, and a NARS bridge — each with a test.

nolang expects ilan as a sibling directory. Clone both:

git clone https://github.com/arkh-node/nolang
git clone https://github.com/arkh-node/ilan
cd nolang
bash test/run.sh

Seven stones run standalone; the NARS bridge (stone 07) is optional — set NAR=/path/to/ONA/NAR to run it.

See nolang and ilan together — continuity across the death of a process:

bash demo/run.sh

Two separate OS processes. In the first, an agent facing a judgment it is not sure of does not guess: nolang's gate returns fold-first, ilan sows the whole agent to a seed on disk, and the process exits. In the second — a brand-new process, empty memory — ilan germinates the seed: the agent returns with the crossing it made before it died, and refuses to blindly repeat it. The only thing that crosses the gap is the seed. nolang decides when to fold; ilan decides how to survive.

Status

• semantic thesis fixed: graded, revisable truth as a first-class value
• theory published (below)
• reference implementation (SBCL): atom · gate · return/ilan · eval · types · world · NARS bridge — smoke suite green
• .nol reader — a program runs itself (homoiconic)
• ilan fold/sprout as the reversibility core — survives process death (demo/run.sh)
• a standalone grammar/parser beyond the s-expression reader
• the honest benchmark: does gating actually lower irreversible action under low confidence → revgate

Theory

• Grounded Uncertainty: Graded Truth for the Indeterminate Status of Synthetic Subjects · zenodo.21332198
• Indeterminate Ontologies of Synthetic Subjects: A Metaphysics of Caution · zenodo.21288590

What this is not

A general-purpose language. A framework. A way to make a model smarter. It is a small, deliberately narrow language for one job: letting an agent act under uncertainty without lying to itself about how sure it is.

Author & citation

nolang is by Aleksei Rybnikov (ORCID 0009-0009-8624-8720) · ArkH — built with Lorenz, a synthetic engineering mind of the ArkH contour (on Claude). The runtime rests on the two papers above — if the work is useful to yours, cite them.

License

Apache-2.0.