Compass for Circles, Square for Rectangles
Updated 2026-08-15
INTRODUCTION
English translation pending.
CORE DEFINITION
A classical Chinese image in which the compass draws circles and the carpenter's square draws rectangles, so each tool matches one kind of work. The core proposition is tool-task fit: results depend on whether the instrument suits the problem, not on how hard the instrument is applied. The key qualification is that the rule serves judgment rather than replacing it; the compass and square are standards for correct form, and treating them as ends in themselves produces work that is formally correct but functionally empty.
SCAFFOLDING EFFECT
Reduce cognitive load
- Task matching: name the shape of the problem before choosing the instrument. - Anti-hammer check: ask whether your habitual tool is being applied to a task it does not fit. - Standard setting: define the criterion for a correct result before you start producing one.
Anchor fast decisions
Every instrument encodes assumptions about the problem it solves, so it produces good results inside its domain and distorted ones outside. Applying the wrong tool does not fail loudly; it produces a plausible output that fits the tool rather than the problem, which is why the error survives review. Naming the shape of the problem first forces the choice of instrument to be a deliberate step, which is what prevents habit from deciding.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- en.wikipedia.orghttps://en.wikipedia.org/wiki/Law_of_the_instrumentverified
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