The square of opposition is a classical diagrammatic tool in logic that illustrates the logical relationships between certain types of categorical propositions. It originates from Aristotelian logic and serves as a visual representation of how different propositions can contradict, contradict indirectly, or imply one another. The traditional square of opposition deals with four types of categorical propositions, often labeled as A, E, I, and O. An A proposition is universal affirmative, asserting that all members of a class possess a certain property, expressed as “All S are P.” An E proposition is universal negative, stating that no members of a class have a certain property, expressed as “No S are P.” An I proposition is particular affirmative, asserting that some members of a class possess a property, expressed as “Some S are P.” An O proposition is particular negative, stating that some members of a class do not possess a property, expressed as “Some S are not P.” The square of opposition organizes these propositions at four corners of a square, with lines connecting them to depict