Logic: Categorical Propositions Flashcards
1
Q
“A” propositions’
A
Universal Affirmative;
“All S are P”
2
Q
“E” propositions’
A
Universal Negative;
“No S are P”
3
Q
“I” propositions’
A
Particular Affirmative;
“Some S are P”
4
Q
“O” propositions’
A
Particular Negative;
“Some S are not P”
5
Q
Square of opposition
A
A and E: Contraries I and O: Sub-contraries A and O: Contradictories E and I: Contradictories "A and I"/ "E and O": Sub-Alternates
6
Q
Contraries
A
Cannot both be true but can both be false
7
Q
Sub-contraries
A
Cannot both be false but can both be true
8
Q
Contradictories
A
have opposite truth values
9
Q
Sub-Alternates
A
the truth of universals implies the truth of the particular;
the truth of the the particular leaves the truth of the universal undetermined.
