All you do is switch the subject and predicate term . You must remember that conversion is only to be used on E and I statements. When you use conversion on an A or O statement, the resulting statement does not necessarily have the same truth value as the original, making it unreliable for drawing inferences. I remember that conversion is valid for E and I statements by looking at the name of the operation. You must replace the predicate term with its complement .
All cats are non-dogs.
Contraposition is easier to perform than obversion, although it also involves a two-step process. You can only contrapose A and O statements, if you want to preserve truth value. You replace both the subject and predicate terms with their complements . To make an inference on the basis of such an operation is to commit a logical fallacy. Venn diagrams These are used as they were in the last lesson , with some modifications to accommodate term compliments .