In the history of human culture, initially the square of opposition was invented and used as a tool for formal logic analysis of thinking and as a handy pedagogical means (visual model) for teaching logic (Correia, M.

The Didactic and Theoretical Expositions of the Square of Opposition in Aristotelian Logic".

Handbook of the Fourth World Congress on the Square of Opposition, p.

A Square of Opposition of Moral-Legal Evaluation-Functions in Two-Valued Algebra of Formal Ethics".

Meinong analyzes deontic relations in terms of their relative values from egoistic and altruistic perspectives, which he expresses in a simplified algebraic notation and arranges in a variation of the Aristotelian square of opposition for four types of categorical statements in syllogisms.

What about acts that are permissible according to Meinong's adaptation of the deontic square of opposition (pp.

The "table" is a square with diagonally connected corners, of the kind most likely to be familiar to readers as the

Square of Opposition, found in elementary logic texts since the mid-19th century.

Manuel Correia, Pontificia Universidad Catolica de Chile, "The Didactic and Theoretical Expositions of the

Square of Opposition in Aristotelian Logic".

I turn for help to logic, specifically to the logical relation that obtains between two pairs of propositions in the square of opposition.

Every S is P" and "Some S is P" are subalternates in the categorical square of opposition.

So the affirmative side of the modal square of opposition may be read directly as the affirmative side of what I might call a square of action (see Appendix 1).

Among the book's virtues must be mentioned its profuse illustration of so many different graphic methods in mathematical logic, including Venn diagrams, the

square of opposition, Smullyan truth trees, Wallen's reduction technique, Beth's and Hintikka's semantic tableaux method, and several styles of axiomatic and natural deduction.