Lesson 5
The fourth part of a proposition; not the subject-term, the predicate-term, or the copula
In this relationship, statements affirm and deny the same predicate of the same subject.
What is opposition?
The relationship between two statements that are both particular but differ in quality
What is sub-contrariness?
The status of a term in regard to its extension
What is distribution?
What are obversion, conversion, and contraposition?
The two characteristics of a proposition
What are quality and quantity?
The four ways propositions can be in opposition to one another
What is contradiction, sub-contrariness, contrariness, and sub-alternate?
The law that says subcontraries may at the same time both be true, but cannot both be false.
What is the third law of opposition?
In these types of propositions, the predicate-term is always un-distributed.
What are affirmative propositions?
The process where you use these 2 steps:
1) Change the quality of the sentence
2) Negate the predicate
What is obversion?
Has to do with whether a proposition is universal or particular
What is quantity?
The relationship between two statements that differ in both quality and quantity
What is contradiction?
The relationship between two statements that have the same quality, but different quantities
What are sub-alternate statements?
The part of a sentence about which something is being said
What is the subject?
Rule that says that a term which is not negated is equivalent to a term that is negated twice
What is the rule of double negation?
Has to do with whether a proposition is affirmative or negative
What is quality?
These statements cannot be at the same time true nor at the same time be false.
What are contradictory statements? (First law of opposition)
These statements can both be true or both be false. If the particular is false, the universal is false. If the universal is true, the particular is true.
What are sub-alternate statements? (Fourth law of opposition)
A diagram that shows the distribution of the terms in a proposition
What is a Euler's diagram?
The process where you use these three steps:
1) Obvert the statement
2) Convert the statement
3) Obvert the statement
What is contraposition?
The four basic types of propositions
What are A statements, E statements, I statements, and O statements?
The relationship between two statements that are both universals but differ in quality
What is Contrariness?
What is sub-contrariness?
The type of statements where the subject term is distributed
What are universal statements?
The process in which you interchange the subject and the predicate
What is conversion?