Under the earlier convention, contraposition reverses the complementary terms while preserving truth and quality. The later convention complements the second term, retains the first term, and reverses quality.
Earlier categorical outcomes:
Universal affirmative → universal affirmative.
Particular affirmative → no general contrapositive.
Universal negative → particular negative, assuming subject existence.
Particular negative → particular negative.
Above all, term complementation, propositional negation, and contradiction must remain distinct. The next independent chapter begins the treatment of arguments and syllogism.