Rigorous Reasoning
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Formal Logic · Free

Venn Diagram Builder

Draw two- and three-circle Venn diagrams to visualize set membership, overlap, and basic categorical claims. Useful for getting a visual handle on syllogistic structure before working with the formal A/E/I/O notation.

Used in: Categorical Logic. This is a visualization sandbox — it doesn't validate categorical propositions automatically. For mechanical validity checking on syllogisms, use the Syllogism Checker; for the underlying distribution rule on a single statement, the Distribution Analyzer.

Venn Diagram Builder

Define your sets, place items into the regions (drag to reposition), and shade regions you want to mark as empty — the classical Venn notation for “no members exist here.”

Diagram type
Set names (or click a label in the diagram to edit it directly)
AB
Add an item to a region — drag it afterward to reposition
2 sets · 0 items placed · 0 regions shaded

Where to go next

Syllogism CheckerTest full categorical syllogisms for validity using the five classical rules. Reports under both modern and traditional interpretation.Open tool →Distribution AnalyzerUnderstand how a single categorical statement distributes its subject and predicate terms — the structural rule that drives validity.Open tool →Truth Table BuilderThe propositional-logic counterpart — useful when you're working with truth-functional formulas instead of class statements.Open tool →