Chapter 7 Flashcards
Deductive Arguments: Categorical Logic
Q: What is Categorical logic?
A: A branch of formal logic in which the basic logical terms are all, some, no, are, and not.
Q: What is a Square of opposition?
A: An arrangement of the four categorical forms. The opposition is apparent from the diagonals on the square.
Q: What are sub contrary statements?
A: An I statement and an O statement with the same subject and predicate. Sub-contraries can both be true, but they cannot both be false. Example: Some flowers are blue; some flowers are not blue.
Q: What is distribution?
A: A term is distributed when the categorical statement in which it appears is about all things within the category designated by the term. The subject (S) term is distributed in A and E statements. The predicate (P) term is distributed in E and O statements.
Q: What is universal affirmative?
A: (A) statement of the form “No S are P.”
Q: What is stereotyping?
A: Thinking, in an unduly simplistic way, of all members of a class or group as being the same, on the grounds that some are. In other words, from the truth of an I statement assuming that an A statement is true. Examples: All Americans resist learning foreign languages; All Canadians love to ski; All Italians eat garlic; All Germans are well-organized. Such errors or stereotyping trade on a failure to carefully distinguish between SOME and ALL.
Q: What is a universal negative?
A: (E) statement of the form “No S are P.”
Q: What is Particular affirmation (I)?
A: Statement of the form “Some S are P.”
Q: What is Particular negative (O)?
A: Statement of the form “Some S are not P.”
Q: Venn diagram
A: Diagram in which overlapping circles are used to represent categorical relationships.
Q: What is immediate inference?
A: Inference of one statement directly from another, with no intermediate logical steps.
Q: What is conversion?
A: A logical operation on a statement in categorical form, in which the order of the terms is reversed. For example, the converse of “All S are P” is “All P are S.” For E and I statements, conversion produces logically equivalent statements. For A and O statements, it does not.
Q: What is logical equivalence?
A: Logical relation between two statements that must necessarily have the same truth value. For instance, “Not all S are I” and “Some S are not I” are logically equivalent.
Q: What is Contraposition?
A: A logical operation on a statement in categorical form, in which the statement is converted, and then non is attached to each category. For example, the contrapositive of “No S are P” is “No non-P are non-S.” For A and O statements, contraposition produces a logically equivalent statement. For E and I statements, it does not.
Q: What is an obversion?
A: A logical operation on a statement in categorical form, in which the prefix non is added to the predicate. Then, if the original statement was affirmative, it was made negative. If the original statement was negative, it is made affirmative. Obversion always produces a statement that is logically equivalent to the original one.
