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But it is to our advantage to study the various forms in which the syllogism may appear and examine the special rules which govern each form. The two determining factors in the form of a syllogism are its figures and moods. A study of these factors will help us to further understand the peculiarities and characteristics of this type of argument even better. Syllogistic Figures When we use the term "syllogistic figure" we understand the disposition of the middle term (M) with respect to the major (P) and minor terms (S) in the premises of a syllogism. The minor term (S) is always the subject and the major term (P) is always the predicate of the conclusion. Whatever variations that can take place in the relative position of the terms among themselves must occur in the premises. In the major premise the middle term is compared with the major extreme. In the minor premise the middle term is compared with the minor extreme. This gives four different syllogistic figures: M P S M P M S M M P M S P M M S S P S P S P S P First Figure M P All animals (M) are a nuisance (P). S M All dogs (S) are animals (M). S P Therefore, All dogs (S) are a nuisance (P). The middle term is the subject of the major premise and the predicate of the minor premise. Second Figure P M No statesmen are good politicians. S M Some journalists are good politicians. S P Therefore, some journalists are not statesmen. The middle term is the predicate of both premises. Third Figure M P All writers are intelligent. M S Some writers are American citizens. S P Therefore, Some American citizens are intelligent. The middle term is the subject of both premises. Fourth Figure P M All Americans are happy people. M S All happy people are fun-loving S P Therefore, Some fun-loving people are Americans. The middle term is the predicate of the major premise and the subject of the minor premise. The First Figure has been considered to be the perfect syllogism because it is the way we tend to make statements normally and naturally. The other three figures, however, are correct forms of syllogistic reasoning, even if they seem to be somewhat stilted and unnatural. Syllogistic Moods Logicians also speak of syllogistic moods. Moods are defined as the arrangement of the premises according to quantity (universal or particular) and quality (affirmative or negative). From the viewpoint of quantity, each of the syllogistic figures can have the following moods: Both premises universal Both premises particular The major premise universal, the minor premise particular The major premise particular, the minor premise universal From the viewpoint of quality, each of the syllogistic figures can have the following moods: Both premises affirmative Both premises negative The major premise affirmative, the minor premise negative The manor premise negative, the minor premise affirmative The following combinations of moods are possible in the construction of premises in each of the four syllogistic figures: O A O E O I O O E A E E E I E O I A I E I I I O A A A E A I A 0 In theory, all these combinations are possible. But half of them are invalid because they violate one or more of the General Rules which govern the syllogism. For example, the E E, E O, O E, and O O combinations are invalid because they violate Rule Number 6, which forbids two negative propositions as premises in an argument. The combinations of I I, I O, and O I are eliminated because Rule Number 8 forbids two particular propositions to be used as the premises in an argument. Although there are sixteen possible combinations, when all is said and done, only eight of them are valid. The eight valid syllogistic moods are: A A A E A I A O E A E I I A O A Now we can combine these valid moods with the four syllogistic figures. We will see what rules govern each figure and how these rules affect the validity of the single moods.  To Page 1-b of Figures and Moods of the Syllogism Enrich Your Life With a Philosophy Book... Enrich Your Life With a Philosophy Magazine... Main Page & Index
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