One universal affirmative gives two distinct results:
Original: Every human is an animal.
Simple converse: Some animals are humans.
Contrapositive: Every nonanimal is nonhuman.
Simple conversion retains the original concepts and exchanges positions. Contraposition introduces complementary concepts in reversed order.
Confusing the operations may change the quantity or meaning of the resulting proposition.
Opening interactive controls...
Contraposition: Classical Rules, Validity and the Later Convention
One universal affirmative gives two distinct results:
Original: Every human is an animal.
Simple converse: Some animals are humans.
Contrapositive: Every nonanimal is nonhuman.
Simple conversion retains the original concepts and exchanges positions. Contraposition introduces complementary concepts in reversed order.
Confusing the operations may change the quantity or meaning of the resulting proposition.