MENTAL MODEL · M4318

Fallacy of Division

StructureHigh supportLogic

Included

Version 1.0.0 · Updated 2026-07-30

CORE DEFINITION

The belief that properties of the whole necessarily apply to its parts. For example: "This machine is heavy, so every part of it is heavy"; "This team is world-class, so every member of the team is world-class."

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

Corrects misjudgments about the micro level. It is the opposite of the Fallacy of Composition. In talent identification or attribution analysis, be wary of "mediocrity under a halo": an excellent system may be composed of mediocre but well-assembled components.

anchor

Anchor fast decisions

A standard formal logical fallacy (fallacy of division). It mistakenly assumes that properties of the whole must be properties of each part. The mechanism is ignoring emergence: properties of the whole often arise from relationships between parts rather than from the parts themselves.

MINIMUM ACTION

In progress 0/3

Practice this model in one real situation:

Identify assertions that go from "whole" to "parts."
Test whether the property can hold for each member.
Use counterexamples to disprove (machine heavy ≠ each part heavy).

Check to track your progress (stored locally)

Learning progress0%

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Source support: Explicit

link
zh.wikipedia.orghttps://zh.wikipedia.org/wiki/%E5%88%86%E5%89%B2%E8%AC%AC%E8%AA%A4ZH · Explicit
verified

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