In Conversion by Contraposition, there is a change in the position of the negative copula, which shifts the expression of the quality. As for instance, in the Particular Negative "Some animals are not horses," we cannot say "Some horses are not animals," for that would be a violation of the rule that "no term must be distributed in the converse which is not distributed in the convertend," for as we have seen in the preceding chapter: "In Particular propositions the _subject_ is _not_ distributed." And in the original proposition, or convertend, "animals" is the _subject_ of a Particular proposition. Avoiding this, and proceeding by Conversion by Contraposition, we convert the Convertend (O) into a Particular Affirmative (I), saying: "Some animals are not-horses;" or "Some animals are things not horses;" and then proceeding by Simple Conversion we get the converse, "Some things not horses are animals," or "Some not-horses are animals." The following gives the application of the appropriate form of Conversion to each of the several four kind of Judgments or Propositions: (A) _Universal Affirmative_: This form of proposition is converted by Limited Conversion. The predicate not being distributed in the convertend, it cannot be distributed in the converse, by saying "all." ("In affirmative propositions the _predicate_ is _not_ distributed.") Thus by this form of Conversion, we convert "All horses are animals" into "Some animals are horses." The Universal Affirmative (A) is converted by limitation into a Particular Affirmative (I). (E) _Universal Negative_: This form of proposition is converted by Simple Conversion. In a Universal Negative _both terms are distributed_. ("In universal propositions, the _subject_ is distributed;" "In negative propositions, the _predicate_ is distributed.") So we may say "No cows are horses," and then convert the proposition into "No horses are cows." We simply convert one Universal Negative (E) into another Universal Negative (E). (I) _Particular Affirmative_: This form of proposition is converted by Simple Conversion. For _neither term is distributed_ in a Particular Affirmative. ("In particular propositions, the _subject_ is _not_ distributed. In affirmative propositions, the _predicate_ is _not_ distributed.") And neither term being distributed in the convertend, it must not be distributed in the converse. So from "Some horses are males" we may by Simple Conversion derive "Some males are horses." We simply convert one Particular Affirmative (I), into another Particular Affirmative (I). (O) _Particular Negative_: This form of proposition is converted by Contraposition or Negation. We have given examples and illustrations in the paragraph describing Conversion by Contraposition. The Particular Negative (I) is converted by contraposition into a Particular Affirmative (I) which is then simply converted into another Particular Affirmative (I).