Rigorous Reasoning
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Definitions · Free

Definition Builder

Build clearer definitions by finding the class, the distinguishing feature, and the boundary cases. The tool walks you through the classical genus-differentia structure without requiring you to learn the Latin first, then helps stress-test your draft against ten common definition problems.

Pairs with: the Definition Tester (which stress-tests a finished definition against examples, non-examples, and borderline cases) and the Argument Repair Tool (since many weak arguments rest on unclear terms — a sharper definition is often the most direct repair). The natural workflow: build here, test in the Tester, revise.

1. The term and your starting point

Start with the word you're trying to define and a rough first attempt. The first attempt is just a starting point — the rest of the tool is for refining it.

2. The class and what makes the term distinct

Most concepts can be defined by saying what kind of thing they are (the class) plus what distinguishes them from other members of that class (the distinguishing feature).

3. Examples and edges

Examples show what counts; non-examples show what doesn't; borderline cases test the definition's sharpness. List a few of each — one per line.

4. Draft definition

Built directly from the parts you wrote above. Edit the parts to change the draft.

Fill in the term plus the class or distinguishing feature to see a draft.