Sanity check¶

Version: v1 · 2026-09-08 · History
Prime #: 1548
Aliases: Sanity test, Plausibility check

Core Idea¶

A sanity check is a deliberately inexpensive preliminary test that detects gross impossibility or inconsistency without attempting complete validation. The abstraction is not exhausted by its familiar source-domain notation. Its autonomous core is rapid necessary-condition screening for gross error before deeper validation.

The operative mechanism is this: A result is compared with conserved quantities, dimensional constraints, limiting cases, rough estimates or independently known ranges; failure halts or redirects analysis, while passage only licenses further checking. The mechanism separates identity from observation. A case does not qualify merely because an observer can describe it using the word sanity check; the constitutive relation must be present in the carrier.

Broad Use¶

arithmetic and estimation. The carrier is a calculation, expected sign and order of magnitude, units and a rough independent estimate. The identity test is that the computed result has compatible dimensions, sign and plausible magnitude. This is a literal instantiation rather than decorative analogy because the carrier, observable organization, conserved relation, variation class, and failure test retain the same roles. The domain accent is mental or back-of-envelope comparison is intentionally coarse. A responsible analysis states scale, observation window, representation and noise model before claiming the structure, then distinguishes the structure itself from the process used to discover, stabilize or exploit it.

Clarity¶

A clear Sanity check claim can be rewritten as a testable sentence: on carrier C at scale S, relation R holds within tolerance T, remains under transformations V, and fails for counterexample K. This grammar exposes missing components and prevents a noun from standing in for an argument.

Manages Complexity¶

Sanity check manages complexity by replacing an unstructured inventory with a small set of relations that survive relevant variation. Compression becomes legitimate when the retained relation supports reconstruction, comparison or reliable discrimination and the discarded details are declared incidental for the task.

The abstraction also supports chunking. Once an organized unit is established, reasoning can treat it as one object while retaining an audit trail to its elements.

Abstract Reasoning¶

Type the carrier and explain why its elements are individuated at the selected scale. 2. Separate the target structure from the notation, image, model or story used to display it. 3. State the constitutive relation as an equation, rule, repeatability condition or traceable interpretive criterion. 4. List transformations expected to preserve identity and justify why they are incidental. 5. Choose at least one positive diagnostic and one collapse test.

Knowledge Transfer¶

Transfer begins from the role graph, not the name. Preserve carrier, relation, invariant, admissible variation, diagnostic and collapse test; then substitute domain occupants. A successful mapping explains how the target case would be recognized and how it would fail.

The most common transfer error is feature substitution. One field may represent the structure visually, another algebraically and another behaviorally. The visible features are not the invariant. Transfer must identify the relation those features evidence and state the target domain's measurement or proof obligations.

Relationships to Other Abstractions¶

Current abstraction Sanity check Prime

Parents (1) — more general patterns this builds on

Sanity check is a kind of Error Proofing (Poka-Yoke) Prime

The accepted reference-grade review places Sanity check under Error Proofing (Poka-Yoke) because the child instantiates or depends on the parent's broader structure while retaining its own constitutive identity.