Logic / Unit 2 Logic 058 worked example, 60 to 90 seconds
Evaluating a Definition
The idea
Evaluating a definition means first identifying what kind of definition it is, then testing it for intruders it wrongly admits, exiles it wrongly excludes, circularity, and emotive wording doing argumentative work.
In practice
Grade three. First: a chair is a piece of furniture with four legs. Hunt for intruders — a table is furniture with four legs, so the definition admits what it should exclude. Too broad. Hunt for exiles — a swivel chair rests on one pedestal, so the definition excludes what it should admit. Too narrow as well, and a definition can fail both ways at once. Second: taxation is the confiscation of a citizen's earnings. The word confiscation delivers a verdict, so the definition settles a political question by wording rather than by argument. Third: a prime number is an integer greater than one whose only positive divisors are one and itself. No intruders, no exiles, no circle, no loaded terms. It passes.
Where people slip
A stipulative definition cannot be graded as too broad or too narrow, because it is not reporting existing usage — it is announcing one for a stated purpose. Testing a stipulation against ordinary usage is a category error, so check the type first or you will fail a definition for missing a target it never aimed at.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Unlocks
- Nothing yet depends on this.
Something wrong in this lesson? Flag it · Sources for Logic