Square of opposition
The square of opposition is a "diagram that illustrates the logical relationships between four types of categorical propositions: universal affirmative (A), universal negative (E), particular affirmative (I), and particular negative (O). It originated with Aristotle and shows how the truth value of one proposition can be used to determine the truth value of another based on relationships like contradiction (Contradictions are statements that cannot both be true or both be false; they always have opposite truth values, such as "it is raining" and "it is not raining), contrariety(Contraries are statements that cannot both be true, but can both be false, such as "the shirt is red" and "the shirt is green," because the shirt could be blue), and subcontrariety."[1]
External links
- Square of Opposition, Internet Encycylopedia of Philosophy
- What is the Ssquare of opposition, AI