square of opposition
Categorical proposition relationships
The square of opposition is a diagram in traditional logic showing how four types of categorical statements relate to each other.
The four corners represent universal affirmative ("All S are P"), universal negative ("No S are P"), particular affirmative ("Some S are P"), and particular negative ("Some S are not P").
Lines connecting the corners show logical relationships: contradiction, contrariety, subcontrariety, and subalternation.
The diagram helps determine which statements can be true together and which cannot.
- contradictionOpposing claims, incompatible together
- contraryOpposed in nature
- four cornersAngular meeting points of edges
- AristotleGreek founder of formal logic
- logicScience of valid reasoning
proposition · universal · particular · affirmative · negative · syllogism · validity · inference · negation · medieval · scholastic · diagram · corners · relations · quantifier · truth value · predicate · subject
- logicpremise, premises, conclusion, conclusions, inference
square of oppositiontruth table
Chart of logical possibilities
Boolean algebra · Venn diagram · binary logic · natural deduction · Karnaugh map
square, squares, squared, squaring, squarely, squareness, opposition, oppositions, oppose