Chapter 5. Categorical Propositions. 1. A deductive argument is one that claims to establish its conclusion conclusively. A valid deductive argument is one in which, if all the premises are true, the conclusion must be true .
Universals distribute Subjects.
Negatives distribute Predicates.
If true: A All men are wicked creatures. If false: or negative—and
false E No men are wicked creatures undetermined
true I Some men are wicked creatures. undetermined
false O Some men are not wicked creatures. true
false A All men are wicked creatures undetermined
false I Some men are wicked creatures. true
true O Some men are not wicked creatures. undetermined
All non-P is non-S is also true.
The relationships among classes in the Boolean interpretation of categorical propositions can be represented in symbolic notation. We represent a class by a circle labeled with the term that designates the class.Thus the class S is diagrammed as shown below:Symbolism and Diagrams for Categorical Propositions