Categorical Syllogism Flashcards
Syllogism
A deductive argument made up of three statements: two premises and a conclusion
Categorical Syllogism
A syllogism consisting of three categorical statements (A, E, I, O) interlinked in a specific way.
Major Term
The predicate term of the conclusion
Major Premise
The premise in which the major term occurs
Minor Term
the subject term of the conclusion
Minor Premise
The premise in which the minor term occurs
Middle Term
appears in each premise once, not not in the conclusion
Mood of a Categorical Proposition
Determined by the standard form of the categorical propositions in the syllogism.
The mood is represented by listing the letters that identify the forms of each categorical proposition.
Figure of a Categorical Proposition
Determined by the position of the middle term in the major and minor premise.
Method for identifying the form of a categorical syllogism
Step 1: Put each prop. into standard form
Step 2: Determine which proposition is the conclusion and which the premises
Step 3: Arrange the premises and conclusion in standard order: major prem.- minor prem.- concl.
Step 4: Identify the mood and write the letters in order
Step 5: Identify the figure and write it down after the mood.
Enthymeme
is a syllogism with an unstated premise or conclusion.
Method for determining the missing premise/ concl.
one must determine what is required to make the syllogism valid and that commits the author to no more that is required.
Rule 1 for validity
The middle term must be distributed in at least one of the premises.
- A term is distributed just in case it occurs in a categorical proposition that makes an assertion about all members of the class the term designates.
- A categorical syllogism is valid only if the middle term is distributed in at least one of the premises.
Rule 2 for validity
If either of the terms in the conclusion is distributed, it must be distributed in the premise in which it occurs.
-If the major term in the conclusion is distributed, then the argument is valid only if the major term in major premise is distributed. If not then the argument commits the fallacy of an illicit minor term.
-If the minor term in the conclusion is distributed, then the argument is valid only if the minor term in the minor premise is distributed. If not then the argument commits the fallacy of an illicit minor term.
Rule 3 for validity
The premises cannot both be negative
-a syllogism is valid only if at least one of the premises is not negative, if not the it commits the fallacy of two negatives.
