# Logic6

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The flashcards below were created by user faulkebr on FreezingBlue Flashcards.

1. Subcontraries
• I and O
• If one is False, the other must be True
• CANT both be false
2. Superalternation
• A has corresponding I
• Ehas corresponding O
• The superaltern implies the TRUTH of its corresponding subaltern
• Cant both be True
• Cant both be False
• A - O
• E - I
4. Contraries
• Cant both be True
• If one is true, the other must be False
• But if one is False, then we can infer nothing about the other
5. Conversion
• Replace the subject and Predicate (just switch)
• Only works for E and I statements
• No S are P = No P are S
• O and A statements cant work (except by lim.)
6. Convert by Limitation
• Turn A statements into I statements
• All Sare P = Some P are S
• Still just switch the S and P
• Only works for A statemets
• One way inference
7. Subcontraries
• I, O
• Cant both be False
• Can both be True
8. Sub alternation
• If one is true you can immediately infer the other is True
• A -> I
• E -> O
• If A or E is False, then their corresponding subalterns are undetermined
9. Obversion
• Used in all statements
• Change quality of proposition (affirmative/Negative)
• Replace predicate term with its complement
• A: all s are p - E: No S are non p
• E: No s are p - A: all s are non p
• I: some s are p - O: some s ar notnonp
• O: Some s is not p-I:some s is non p
10. Contraposition
• replace the subject term with the complement of the predicate term
• Replace the predicate term with the complement of its subject term
• Not all contrapositives are valid
11. Contrapositive by lim.
• works only for E statements
• E -> O

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 Author: faulkebr ID: 112393 Filename: Logic6 Updated: 2011-10-26 21:43:26 Tags: Square opposition Folders: Description: 6.5 Show Answers:

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