_Cesare_. Festino. If A is B, C is never D. If A is B, C is never D. C is always D. C is sometimes D. .'. A is never B. .'. A is sometimes not B. § 747. As the partly conjunctive syllogism is thus reducible to the simple form, it follows that violations of its laws must correspond with violations of the laws of simple syllogism. By our throwing the illicit moods into the simple form it will become apparent what fallacies are involved in them. _Denial of Anteceded_. If A is B, C is D. \ / All cases of A being B are cases of C \ = / being D. A is not B. / \ This is not a case of A being B. .'. C is not D. / \ .'. This is not a case of C being D. Here we see that the denial of the antecedent amounts to illicit process of the major term. § 7481 _Affirmation of Consequent_. If A is B, C is D. \ / All Cases of A being B are cases of C | = | being D. C is D. / \ This is a case of C being D. Here we see that the affirmation of the consequent amounts to undistributed middle. § 749. If we confine ourselves to the special rules of the four figures, we see that denial of the antecedent involves a negative minor in the first figure, and affirmation of the consequent two affirmative premisses in the second. Or, if the consequent in the major premiss were itself negative, the affirmation of it would amount to the fallacy of two negative premisses. Thus-- If A is B, C is not D. \ / No cases of A being B are cases of C | = | being D. C is not D. / \ This is not a case of C being D. § 750. The positive side of the canon of the conjunctive syllogism--'To affirm the antecedent is to affirm the consequent,' corresponds with the Dictum de Omni. For whereas something (viz. C being D) is affirmed in the major of all conceivable cases of A being B, the same is affirmed in the conclusion of something which is included therein, namely, 'this case,' or 'some cases,' or even 'all actual cases.' § 751. The negative side--'to deny the consequent is to deny the antecedent'--corresponds with the Dictum de Diverse (§ 643). For whereas in the major all conceivable cases of A being B are included in C being D, in the minor 'this case,' or 'some cases,' or even 'all actual cases' of C being D, are excluded from the same notion.