Some non-A are not B. (T) Some non-B are not A.
A) Conversion. (Und.)
B) Contraposition. (Und.)
C) Contraposition. (T)
D) Subcontrary. (F)
E) Subcontrary. (Und.)

Question

Quizplus · Accepted Answer

Contraposition is valid in both directions. Therefore, if we negate the proposition and switch the subject and predicate terms, we get another true proposition. In this case, the negation of "Some non-A are not B" is "No non-A are B", which can be written as "All B are A" (contrapositive form). By switching the subject and predicate terms, we get "All A are B", which can be written as "No non-B are A". This is the same as the statement "Some non-B are not A", making option C true.

Some Non-A Are Not B