Logic6

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

Subcontraries
- I and O
- If one is False, the other must be True
- CANT both be false
Superalternation
- A has corresponding I
- Ehas corresponding O
- The superaltern implies the TRUTH of its corresponding subaltern
Contradictories
- Cant both be True
- Cant both be False
- A - O
- E - I
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
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.)
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
Subcontraries
- I, O
- Cant both be False
- Can both be True
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
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
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
Contrapositive by lim.
- works only for E statements
- E -> O

Card Set Information

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