Running header: Square of
Opposition
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Square of Opposition
Amber Lee
West Coast University
Running header: Square of
Opposition
2
Merriam-Webster defines logic as
a science that deals with the rules and processes used
in sound thinking and reasoning.
Categorical logic is defined as logic based on the relations of
inclusion and exclusion among classes or “categories” as stated in categorical claims (Moore &
Parker,2017). Categorical logic is useful in clarifying and analyzing deductive arguments.
The square of opposition is a chart that represents the relationships between categorical
propositions. The square is usually drawn to look like this:
(2016).
The four corners of the square account for the four basic forms of categorical propositions. The
A is for universal affirmatives- All S are P; E for universal negatives- No S are P; I is for
particular affirmatives- Some S are P and, O for particular negatives- Some S are not P.
The lines drawn between the letters are for the relationships between the logics. There
are four types of relationships. Universal affirmatives (A) are contradictory to negatives (O). The
