II. Three categorical propositions
III. General Rules
1) Number of terms in the syllogism.
2) How to determine the three terms in the syllogism.
3) Distribution of the major and minor terms in the syllogism.
4) Distribution of the major and minor terms in the syllogism.
5) The quality of the premises.
6) The quality of the premises.
7) The quality of the premises.
8) The quantity of the premises.
9) The quantity of the premises.
1) SUB-PRE (Subject-predicate)
2) PRE-PRE (Predicate-predicate)
3) SUB-SUB (Subject-subject)
4) PRE-SUB (Predicate-subject)
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Violation of this is called fallacy of 4, 5 or 6 terms.
All birds are animals.
Tweety is a bird.
Tweety is an animal.
2) The major term (T) is the predicate of the conclusion and should appear in the first premise; the minor term (t) is the subject of the conclusion and should be found in the second premise and the middle term (M) is found in both premises but in the conclusion.
Diamonds are precious.
But diamonds are stones.
Stones are precious.
3) The major and minor terms should not be universal in the conclusion if they are not universal in the premises. Violation of this rule is called fallacy of illicit major/minor.
All teachers are nice.
Bernard is a teacher.
Bernard is nice.
4) The middle term must be universal at least once. Violation of this rule is called undistributed middle.
All athletes are sickly.
But no healthy are sickly.
No sickly are athletes.
5) If both premises are affirmative, the conclusion must be affirmative. Violation of this commits the fallacy of drawing a negative premise from affirmative premises.
All sins are detestable.
But some pretense is sin.
Some pretense is detestable.
6) If a premise is affirmative and the other is negative, the conclusion must be negative. Violation of this commits the fallacy of drawing an affirmative conclusion from negative premise.
A man is two-legged.
But a horse is not a two-legged.
A horse is not a man.
7) If both premises are negative, no conclusion possible. Violation of this commits the fallacy of exclusive premises. Any negative premise denies inclusion. Hence, one cannot assert any relationship between the major and minor term.
Every immaterial is not mortal.
But human soul is not material.
Human soul is not mortal.
8) At least one premise must be universal. To violate this rule is to commit the fallacy of either illicit major, undistributed middle or two negative premises.
All Russians are communists.
Some atheists are Russians.
Some atheists are communists.
9) If one premise is particular and the other is universal, the conclusion must be particular. To violate this rule is to commit the fallacy of either illicit major, illicit minor or undistributed middle.
No Americans are small.
Some Filipinos are Americans.
Some Filipinos are not small.
Figures refers to the arrangement of middle term in the syllogism. So middle term becomes the basis of the arrangement to the other terms.
1) SUB-PRE (Subject-predicate)
The syllogism is known to have a sub-pre figure if the middle term is the subject of the first premise and the predicate of the second premise.