4 Chapter 8: Operations for Logical Equivalencies–conversion, obversion and contra-position

Conversion Obversion Contraposition Knachel Chapter 3 Sections IV & V logical equivalencies

In this chapter by Matthew Knachel and Maureen Sander-Staudt, we learn three operations that can help us to create new categorical propositions that may or may not be logically equivalent to the original.  These operations are conversion, obversion and contra-position.  When a categorical statement is logically equivalent to another, its meaning and truth value are retained.  This skill is helpful for discerning when two categorical statements in ordinary language mean the same thing, or not.  We can also use these operations to test immediate inferences for validity, or in some cases, to create a valid inference.