The Square of Opposition:

 

 

 

 

Arrange the four types of statements around a square as we have here.

"All S is P." is a universal affirmative -- call it an A statement (from Latin Affirmo).

 

"No S is P." is the universal negative, or denial, call it an E statement (from Latin Nego).

 

"Some S is P."  is the particular affirmative -- call it an I statement (from the "I" in Affirmo).

 

"Some S is not P." is the particular negative, or denial -- call it an O statement (from the "O" in Nego).

 

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