Abstract of Logic, Book 2 · Chapter 7
CHAP. VII. Of the three Figures of Syllogiſm and their Modes.
Ax. 1. THE Figures of Syllogiſm are three, becauſe ſo many Ways may the Argument be diſpos'd with the Parts of the Queſtion,
Ax. 2. The firſt of which is, that in which the Argument is ſubjected to the Major, and predicated of the Minor Term: As for Inſtance,
Every Animal feels:
Every Man is an Animal:
And therefore every Man feels.
In which the laſt Extreme or Subject is plainly Man the firſt or Predicate feels; Medium, Animal. Where Man is contain'd under Animal, and Animal that which feels. Let us ſee another Argumentation, viz. This.
No Animal is a Stone:
Every Man is an Animal:
And therefore no Man is a Stone.
Here the Minor indeed is contain'd in the middle; For Man is an Animal; but the Middle not in the Predicate: For Man is not a Stone, &c.
Ax. 3. Now the ſecond Figure or Faſhion of Argumentation is that in which the Argument is predicated of both Extremes.
Every Animal feels:
No Plant feels:
And therefore no Plant is an Animal.
In which the Term Feels which is the Medium is predicated of one affirmatively, the other Negatively; and ſo both.
Ax. 4. The third is, that in which the Argument is the Subject of both Extremes: as,
Every Animal feels:
Every Animal lives:
Something therefore, that lives, or is living, feels.
In which we ſee the Argument Animal is ſubjected both to Feels and Lives, they being both ſaid of it, &c.
There are not wanting thoſe that conceive the Medium may be diſpos'd in a fourth Manner, with the Parts of the Queſtion; and ſo that there is a fourth Figure, in which the Argument may be predicated of the greater Extreme, and ſubjected to the leſs: For Example:
Every Man is an Animal:
Every Animal feels:
Something therefore that feels is a Man.
duplicate page duplicate page In which we ſee the Term Animal is ſaid of Man, and the Term Feels, of it, which is the leſſer Extreme: But ſuch Syllogiſms as theſe, conclude indirectly in the firſt Figure. For of the two Extreme Terms, that is to be eſteem'd the Major which is predicated of the Medium, that the leſſer which is ſubject to it. If both are ſubjected, as in the ſecond, or both predicated as in the third, then that is to be adjudged Major which is the firſt, and that Minor which is the laſt conjoyn'd with the Medium. Of the Propoſitions, that the Major in which the Major; that the Minor in which the Minor is conjoin'd with the Medium: And the Concluſion is ſo to be inferr'd as that the Major Term be the Predicate, and Minor the Subject of it; for if otherwiſe the Concluſion will be indirect. For Example: In the Syllogiſm of the fourth Figure above: Animal is the middle Term, Feels, therefore muſt be the Major, becauſe predicated of Animal; and Men the Minor, becauſe Subject; From whence follows that this Propoſition, Every Animal feels; is the Major Propoſition, becauſe therein the Major Term is joyn'd to the Medium, and this, Every Man is an Animal; Minor, becauſe therein the Medium is joyned with the Minor: And conſequently this the Concluſion, viz. Every Man therefore feels; Not this, viz. Something which feels is Man: For when the Minor Term is collected from the Major, the Syllogiſm is Indirect, &c.
Ax. 5. Now the Modes, viz. Univerſal, certainly and directly concluding, are fourteen: Four in the firſt Figure, viz. Barbara, Celarent, Darii, Ferio; as many in the ſecond. Ceſare, Cameſtres, Feſtino, Baroco; and ſix in the third, viz. Darapti, Felapton, Diſamis, Datiſi, Bocardo, Feriſon.
1. §. All which for the ſake of Memory are contain'd in theſe four Verſicles, ſuch as they could be render'd from the Latin.
Barbara, Celarent, are of the Firſt, alſo Darii Ferio.
Ceſare Cameſtres, of the ſecond; likewiſe Feſtino, Baroco.
The Third Darapti claims and its Felapton,
And with them, Diſamis, Datiſi, Bocardo, Feriſon.
Ax. 6. Of which Words, each Syllable is to be prefix'd to each Propoſition; to ſhew its Quantity and Qualities by its Vowels:
Ax. 7. The Vowels are Four. viz. A, E, I, O. Whereof A, denotes a Univerſal Affirming; E, a Univerſal Denying; I, a Particular Affirming; and O, a Particular Denying.
1. §. All which are likewiſe particularly Expreſs'd in this Couplet, viz.
A aſſerts, E denys, but generally both:
I aſſerts, O denys, but ſpecially both.
Ax. 1. Now Indefinite Propoſitions are all here taken for Particulars, as alſo Singulars, if adjoin'd in the ſame Syllogiſm, to a Propoſition Univerſal or Particular; For if alone, they conſtitute Singular Syllogiſms, or Expoſitory.
Ax. 9. Of which in each Figure there are two; of which thoſe of the firſt and ſecond are leſs Natural; becauſe a Singular is Naturally affirmed of no other.
1. §. Examples of the Univerſal Moods certainly and directly, concluding in the firſt Figure, are ſuch as theſe, viz.
Barbara.
Every Animal feels;
Every Man is an Animal:
Every Man therefore feels.
Celarent.
No Animal is a Stone;
Every Man is an Animal:
No Man threfore is a Stone.
Darii.
Every Colour is viſible;
Some Quality is a Colour:
Some Quality therefore is viſible.
Ferio.
No Virtue is an Extreme;
Some Habit is a Virtue:
Some Habit therefore is not an Extreme.
2. §. Of the Singulars in this Figure, the one affirms, the other denies. For Example:
The Meſſiah was to be crucified;
Jeſus Chriſt is the Meſſiah:
Therefore Jeſus Chriſt was to be crucified.
Ariſtotle was not an Athenian;
The Maſter of Alexander was Ariſtotle:
The Maſter of Alexander therefore was not an Athenian.
3. §. Examples of the Univerſal certainly and directly concluding in the ſecond Figure, are ſuch as theſe;
Ceſare.
No rich Man is in Want:
Every Covetous Man is in Want:
No Covetous Man therefore is Rich.
Cameſtres.
Every Animal is mortal;
No Angel is mortal:
No Angel therefore is an Animal.
Feſtino.
No Animal is a Plant;
Something living is a Plant:
Something living therefore is not an Animal.
Baroco.
Every Man is an Animal;
Some Rational Subſtance is not an Animal:
Some Rational Subſtance therefore is not a Man.
4. §. The ſingular Modes of the ſecond Figure conclude both Negatively. For Example:
Plato was not a Stagyrite;
Ariſtotle was a Stagyrite:
Ariſtotle therefore was not Plato.
Ariſtotle was a Stagyrite;
Plato was not a Stagyrite:
Plato therefore was not Ariſtotle.
5. §. Examples of Univerſals certainly and directly concluding in the third Figure, are ſuch as theſe, viz.
Darapti.
Every Virtue is hard to attain to;
Every Virtue is honeſt:
Something therefore honeſt is hard to attain to.
Felapton.
No Stone lives;
Every Stone is naturally mov'd to its own Place:
Something therefore which is naturally mov'd to its own Place, does not live.
Diſamis.
Some Man raves, or is mad;
Every Man is a Rational Animal:
Some Rational Animal therefore raves or is mad.
Datiſi.
Every Covetous Man is in want;
Some Covetous Man has Riches or Wealth:
Some one therefore who has Riches or Wealth, is in want.
Bocardo.
Some Body is not Corruptible;
Every body conſiſts of Matter and Form:
Something therefore which conſiſts of Matter and Form is not Corruptible.
Feriſon.
No Virtue brings forth Miſery;
Some Virtue is painful:
Something therefore which is painful brings not forth Miſery
6. §. Of the Singular Moods in the third Figure, the one alſo affirms, and the other denies. For Example:
Judas was wicked;
Judas was an Apoſtle:
Some Apoſtle therefore was wicked.
Socrates was not a wicked Man:
Socrates was a Heathen:
Some Heathen therefore was not a wicked Man.
7. §. And theſe are the direct Modes, the Uſe of which is much the greateſt in Diſputation: To which Ariſtotle has alſo added ſome Inverted, which from a Major affirming Univerſal or Particular, and Minor Denying, conclude a Particular Negation of the Minor Term. As,
Every Man is an Animal;
No Horſe is a Man:
Some Animal therefore is not a Horſe.
Some Animal is a Man;
No Plant is an Animal:
Some Man therefore is not a Plant, &c.
But theſe, together with the Ways of Converſion and Tranſpoſition, as being uſeful to very few, are better ſought for out of the Inſtitutions: And ſo we proceed to the 8th Chapter, viz. that of the Rules, Laws and Proprieties of Syllogiſms, as far as ſutes to our Purpoſe.