Boundary Condition Memo¶
Document — instantiates Correspondence Violation Detection and Theory Refinement
The ratified, versioned statement of the refined domain of validity that a diagnosed correspondence violation produces — valid inside here, not to be trusted outside there.
A Boundary Condition Memo is the short authoritative document that, once a violation has been diagnosed, states the refined domain of validity: the boundary inside which a formulation may be trusted, outside which it may not, plus the variable and threshold that mark the edge. Its defining quality is that it is a settled conclusion of record, not an investigation and not a proposal — a single canonical sentence of "valid for X, not for Y, because Z," stamped with a version so the scope change is traceable. Where other mechanisms find which premise broke or where along a parameter axis, the memo is where the resulting scope statement is written down, ratified, and circulated as the thing everyone now cites. It closes a refinement by narrowing a claim, and it protects the cases that were already valid by naming them explicitly as still-inside-the-boundary.
Example¶
A pharmacokinetics group has long used a one-compartment linear model for a drug, assuming dose-proportional exposure — double the dose, double the area-under-the-curve. During a high-dose study the exposure at 400 mg comes in well above proportional, breaking correspondence with the linear model. Diagnosis (from an assumption audit and a dose sweep) points to saturable hepatic metabolism setting in above roughly 350 mg. The Boundary Condition Memo records the outcome in a few lines: "The linear one-compartment model is valid for single oral doses ≤ 300 mg in adults with normal hepatic function. Above 300 mg, exposure is supra-proportional; use the saturable-elimination model. Change v2.3 — supersedes the unqualified dose-proportionality claim; motivating case: HD-04 anomaly; low-dose cases below 300 mg remain protected and unchanged." That memo becomes the reference the next analyst reads before choosing a model.
How it works¶
- Precondition: a diagnosed, stable violation. The memo is written only after a violation has been localized and confirmed — never off a single noisy point.
- State old scope, new scope, and the edge. Name what was previously claimed, the refined domain, and the boundary variable with its threshold (a hard cut or a fuzzy band).
- Name what is protected. List the known-valid cases that remain inside the boundary, so the refinement is visibly narrowing, not overturning.
- Stamp the change. Record a version, date, the superseded claim, and the motivating case, so a future reader can reconstruct why the scope moved.
Tuning parameters¶
- Boundary sharpness — a hard threshold versus a graded transition band. A crisp line is easy to apply but false where the failure is gradual; a band is honest but harder to act on.
- Conservatism margin — how much safety margin to leave inside the stated boundary. Wider margins reduce risk but shrink the usable domain.
- Versioning granularity — whether every scope tweak earns a new version or only material changes. Fine versioning gives a rich trail but clutters the log.
- Circulation scope — how widely the memo is pushed. Narrow circulation is cheap but lets stale scope claims survive in corners of the organization.
When it helps, and when it misleads¶
Its strength is that it stops ad hoc patch accumulation[n1] — instead of a theory sprouting scattered, unwritten exceptions, there is one clear scope statement of record. Because it names its motivating case and protects prior successes explicitly, it also makes future review possible: a later team can see exactly why the boundary moved and what it was careful not to break.
Its failure mode is the premature or over-narrow memo: freezing a boundary from an under-diagnosed or still-noisy violation, or drawing the domain so tightly that genuinely valid range is discarded. There is a subtler risk in the opposite direction — a memo treated as permanent scripture becomes old-theory entrenchment, the boundary defended long after new evidence should have moved it. The guarding discipline is to require that every memo cite the diagnosing evidence and carry a review trigger — a condition (new data, a new regime) that reopens it — so the boundary stays a living statement rather than a tombstone.
How it implements the components¶
The memo fills the record-the-refined-scope end of the machinery:
boundary_condition_extractor— it is the extracted boundary made explicit: the refined domain of validity, its edge variable, and its threshold, written as the statement of record.versioned_theory_change_log— the version stamp, superseded-claim note, and motivating-case reference make the scope change a traceable log entry rather than a silent edit.
It does not implement divergence_signature or refinement_hypothesis_generator — capturing the per-violation fingerprint and the proposed fix is the job of Failure Mode Annotation Card. The card is the working dossier of one violation-in-progress; the memo is the settled domain-of-validity conclusion drawn once that work resolves.
Related¶
- Instantiates: Correspondence Violation Detection and Theory Refinement — the memo is where a completed refinement is recorded as a new statement of scope.
- Consumes: Assumption Audit Worksheet and Parameter Sweep Matrix — the diagnosis and the located breakpoint the memo turns into a ratified boundary.
- Sibling mechanisms: Anomaly Triage Board · Assumption Audit Worksheet · Expert Adjudication Panel · Failure Mode Annotation Card · Limiting-Case Test Suite · Overlap-Regime Benchmark Table · Parameter Sweep Matrix · Regression Correspondence Harness · Residual Divergence Map
Editorial Notes¶
Form Classification¶
Form family: Representation, Specification & Plan
Rationale: The ratified, versioned statement of the refined domain of validity that a diagnosed correspondence violation produces — valid inside here, not to be trusted outside there, making its operative form a non-executable information artifact that externalizes static or prospective structure.
Independent corroboration: The frozen evidence defines Boundary Condition Memo as 'The ratified, versioned statement of the refined domain of validity that a diagnosed correspondence violation produces — valid inside here, not to be trusted outside there', so its operative form is Representation, Specification & Plan.
Review outcome: Independent reviewer agreement; high confidence.
Origin Attribution¶
Primary origin: Philosophy
Origin pattern: Cross-disciplinary synthesis
Present-day reach: Multi-domain
Rationale: Explicitly limiting a claim to the conditions under which correspondence holds is a philosophy-of-science treatment of scope and theory revision.
Related originating lineages:
- Engineering & Design — Validated operating envelopes and controlled technical memoranda provide the implementation form.
- Statistics & Experimental Design — External validity and model checking supply evidence for where a claim can and cannot be trusted.
Review resolution: Philosophy of science is the agreed primary lineage because empirical exceptions narrow a claim's domain of validity. Engineering operating envelopes and statistical external validity supply the evidence and implementation form; the ratified memo is a multi-domain Encyclopedia synthesis rather than a literally universal legal or cataloging artifact.
Encyclopedia synthesis: The exact catalogued form synthesizes established practice rather than reproducing a single standard historical label.
Review outcome: Reconciled after independent review; high confidence.
Notes¶
[n1] An ad hoc hypothesis, in Karl Popper's sense, is a modification bolted onto a theory solely to rescue it from a specific refuting case, adding no independent testable content. A boundary memo is the disciplined alternative: rather than patching the theory case by case, it makes one explicit, reviewable statement of where the theory does and does not hold. ↩