Formal logic is logic that deals with the form or logical structure of statements and propositions.  In syllogistic or traditional logic, a categorical proposition is a statement that affirms or denies the predicate of all or part of the subject.  Categorical propositions are important because they provide additional context by comparing one thing to another.  Here are the four types of categorical propositions: A-propositions: All S are P E propositions: All S are not P I propositions: Some S are P O propositions: Some S are not P  Propositions that refer to all or none are called... Show more

Formal logic is logic that deals with the form or logical structure of statements and propositions. 
In syllogistic or traditional logic, a categorical proposition is a statement that affirms or denies the predicate of all or part of the subject. 

Categorical propositions are important because they provide additional context by comparing one thing to another. 

Here are the four types of categorical propositions:
A-propositions: All S are P
E propositions: All S are not P
I propositions: Some S are P
O propositions: Some S are not P 

Propositions that refer to all or none are called universal propositions. Propositions that refer to some are called particular propositions. 

Here are some examples of categorical statements: "All cats are animals, "No fish are birds, "Some fish are ..., and "All human beings are mortal. 

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