5. Numbers — confidence, weight, provenance

ThoughtML lets you attach numbers to beliefs — but it’s careful about them. There is one way to express each thing, and numbers can declare where they came from.

Confidence — on a stance

confidence says how strongly an agent holds a target. It can be:

• a scalar in 0..1 — confidence 0.9
• a range (lo..hi) for honest uncertainty — confidence 0.45..0.70
• the unknown marker ? — confidence ? (held, but credence not stated)

ops-agent holds cache-is-safe
  confidence 0.9

Weight — on a link

weight (0..1) says how strongly a relation holds — how much this piece of evidence counts:

link firms-cutting-headcount supports displacement-hypothesis
  weight 0.85

link technology-creates-jobs undercuts displacement-hypothesis
  weight 0.5

There is deliberately no strongly / weakly adverb. Earlier versions had them; each smuggled in a magic number the author never chose. Strength is the explicit numeric weight, or nothing.

Probability — on a leads-to link

For decision analysis, a leads-to edge carries the probability of that outcome:

link harvard leads-to harvard-thrive
  probability 0.7

(weight and probability are distinct: weight is evidential strength; probability is outcome likelihood. Putting weight on a leads-to edge, or probability on anything else, is ignored with a warning.)

Quantities — on a focus

A focus can carry a typed measure with a unit, classified into a dimension:

focus aid-offer
  quantity 78000 USD
  Annual grant aid offered — grants, not loans.

Units are recognized across dimensions (time, information, currency, count, rate, ratio). Fused forms work too — 200ms, 1.5GB, 30%. See Numbers, units, provenance for the full model.

Provenance — where a number came from

Any authored number can declare its basis inline — one of measured, estimated, assumed:

ops-agent holds cache-is-safe
  confidence 0.9 assumed

focus disk-budget
  quantity 30 GB measured

This is the honest core of the language: a 0.9 that says it’s assumed tells you something a bare 0.9 hides. Provenance is optional — but you can make it mandatory:

thoughtml --strict-provenance doc.thml

With --strict-provenance, any authored quantity, confidence, weight, or probability that omits a basis gets a warning. It’s off by default, so existing documents stay clean.

Our document so far

We add the provenance to our stance — the 0.9 is assumed, not measured:

ops-agent holds cache-is-safe
  confidence 0.9 assumed
  note Shipping — the load test passed.

That single word is what makes the final mirror reading land. But first, one more dimension: time.