PowerPoint Presentation: The purpose of the categorical syllogism is to show how three classes relate to each other. s M P
Categorical Syllogisms must contain three terms.: Categorical Syllogisms must contain three terms. All S are M All M are P _________ Some P are S
Middle term: this term occurs in both premises:: Middle term: this term occurs in both premises: All S are M All M are P _________ Some P are S
Minor term: this term occurs in the subject term of the conclusion and occurs in the minor premise. : Minor term: this term occurs in the subject term of the conclusion and occurs in the minor premise. All S are M All M are P _________ Some P are S
Major term: this term occurs in the predicate term of the conclusion and occurs in the major premise. : Major term: this term occurs in the predicate term of the conclusion and occurs in the major premise. All S are M All M are P _________ Some P are S
Two attributes can be used to describe categorical syllogisms:: Two attributes can be used to describe categorical syllogisms: Mood: Type of statements in the syllogism. Figure: Placement of the middle term.
Mood: AAI: Mood: AAI All S are M All M are P _________ Some P are S
Figure: refers to the placement of the middle term: : Figure: refers to the placement of the middle term: M P S M _________ S P P M S M _________ S P M P M S _________ S P P M M S ________ S P 1 2 3 4
Mood: AAI Figure: 4: Mood: AAI Figure: 4 All S are M All M are P _________ Some P are S
It is possible to reconstruct a syllogism based on mood and figure:: It is possible to reconstruct a syllogism based on mood and figure:
EAI-3: EAI-3 No are All are __________ Some are
EAI-3: EAI-3 No M are All M are __________ Some are
EAI-3: EAI-3 No M are All M are S __________ Some S are
EAI-3: EAI-3 No M are P All M are S __________ Some S are P
Validity for Categorical Syllogisms:: Validity for Categorical Syllogisms: Figure 1 Figure 2 Figure 3 Figure 4 AAA EAE IAI AEE EAE AEE AII IAI AII EIO OAO EIO EIO AOO EIO
Five Rules for Validity of Categorical Syllogisms : Five Rules for Validity of Categorical Syllogisms
Rule 1: The middle term must be distributed at least once. : Rule 1: The middle term must be distributed at least once. Fallacy: undistributed middle All S are M Some P are M ____________ All P are S
Rule 2: If a term is distributed in the conclusion then that term must also be distributed in the premise. : Rule 2: If a term is distributed in the conclusion then that term must also be distributed in the premise. Fallacy: illicit major/illicit minor All M are S Some P are M ____________ All P are S
Rule 2: Doesn’t apply if there are no terms distributed in the conclusion. : Rule 2: Doesn’t apply if there are no terms distributed in the conclusion. No fallacy All M are S Some P are M ____________ Some P are S
Rule 3: Two negative premise are not allowed. : Rule 3: Two negative premise are not allowed. Fallacy: exclusive premises No S are M Some P are not M ____________ Some P are S
Rule 4: If the conclusion is affirmative, there must be no negative premises. If the conclusion is negative, there must be one negative premise. : Rule 4: If the conclusion is affirmative, there must be no negative premises. If the conclusion is negative, there must be one negative premise. Fallacy: drawing affirmative/negative conclusion from negative/affirmative premises. All S are M No P are M ____________ All P are S
Rule 5: If the conclusion is particular, there must be at least one particular premise. : Rule 5: If the conclusion is particular, there must be at least one particular premise. Fallacy: existential fallacy All M are S All P are M ____________ Some P are S
Rule 5: Arguments that violate ONLY rule 5 are conditionally valid: Rule 5: Arguments that violate ONLY rule 5 are conditionally valid Conditionally valid No M are S All P are M ____________ Some P are not S
If an argument violates any one of the first four rules it is invalid.: If an argument violates any one of the first four rules it is invalid.