Square of Opposition - Exam #1 Flashcards
What is the form of an A?
All S are P.
What is the form of an E?
No S are P.
What is the form of an I?
Some S are P.
What is the form of an O?
Some S are not P.
What quality is common to both A and E?
Universal.
What quality is common to both I and O?
Particular.
What quality is common to both A and I?
Affirmative.
What quality is common to both E and O?
Negative.
What letters are connected by contradiction, and by what truth relationship?
A and O, E and I. If one of them is true/false, the other must be the opposite.
What letters are connected by contrariety, and by what truth relationship?
A and E. If one is true, the other must be false, but not vice versa.
What letters are connected by sub-contrariety, and by what truth relationship?
I and O. If one is false, the other must be true, but not vice versa.
What letters are connected by subalternation, and by what truth relationship?
A and I, E and O. If A or E is true, that I or O must be true respectively.
What letters are connected by superalternation, and by what truth relationship?
A and I, E and O. If I or O is false, that A or E must be false respectively.
How does conversion work, and what letters are connected by it?
Reverse the S and P.
I - I
E - E
(If true)
A - I
E - O
How does obversion work, and what letters are connected by it?
Negate the copula, then the predicate. A - E E - A I - O O - I
How does contraposition work, and what letters are connected by it?
First obvert, then convert, then obvert.
A - A
E - O
O - O
What does Euler’s Circle for A look like?
A circle representing S inside a circle representing P.
What does Euler’s Circle for E look like?
Two completely separate circles representing S and P.
What does Euler’s Circle for I look like?
A Venn diagram with S on the left, P on the right, the outside of S as a dashed line, and X’s within the overlap.
What does Euler’s Circle for O look like?
A Venn diagram with S on the left, P on the right, the left of the overlap as a dashed line, and X’s within the S-alone section.