logical opposition (social philosophy and logic)
TRANSCRIPT
Good Day Every One!!!
This Video is all about the Four kinds of Logical Opposition.
Our final Project for Humanities II(Social Philosophy and Logic)
…………….Enjoy Watching……………..
It refers to the relationship existing
between two proposition having the same
subject and the same predicate but differ
in quantity or in quality or in quality or
both in quantity or quality.
LOGICAL OPPOSITION
Four Kinds of Logical Opposition
1. Contrary Opposition2. Contradictory Opposition
3. Sub- Contrary Opposition
4. Sub- Altern Opposition
1. Contrary Opposition
One which exist between two universal proposition that differ in quality
Two propositions with the same subjects and predicates but different qualities and having the same universal quantities.
Rules:
a. Contrary proposition cannot be true together.
b. Contrary propositions can be false together.
Examples:A: All Cats are Dogs. (F) A: All Diamonds are Gems. (T)E: No Cats are Dogs. (T) E: No diamonds are Gems. (F)
A: All Flowers are Roses. (F)E. No Flowers are Roses. (F)
Thus, “If one is true the other is false; If one is false the other is doubtful.”
2. Contradictory Opposition
One which exist between two propositionthat differ in both quality or quantity
Two propositions with the same subjectsand predicates but different in quantitiesand in qualities.
Rules:
a. Contradictory proposition cannot be true together.
b. Contradictory proposition cannot be false together.
Example:
A: All Dogs are Animals. (T)O: Some Dogs are not Animals. (F)
E: no women are married. (F)I. Some Women are married. (T)
Thus, “If one is true the other is false or vice versa.”
3. Sub- Contrary Proposition
One which exist between two particularpropositions that differ only in quality.
Two particular propositions with the samesubjects and predicates but differentqualities.
Rules:
a. Sub-Contrary Proposition cannot be false together.
b. Sub-Contrary proposition may be true together.
Examples:
I: Some Basketball Players are tall. (T)O: Some Basketball Players are not tall.
O: Some Triangles are not Squares. (T)I; Some Triangles are Squares. (F)
I: Some Students are present. (F)O: Some Students are not present. (T)
Thus, “If one is true the other is false; If one is true the other is doubtful.”
4. Sub- AlternOpposition
One which exist between two propositionsthat differ in quality.
Two propositions with the same subjectsand Predicates both with the samequalities and different only in qualities.
Rules:
a. Sub-Altern Proposition cannot be false together.
b. Sub-Altern Proposition can be true together.
Examples:
A: All Dogs are Animals.(T)I: Some Dogs are Animals. (T)
E: No Cats are Dogs. (T)O: Some Cats are not Dogs. (T)
Thus, “If the universal is true the particular is true but if the universal is false, the particular is doubtful or vice versa.
The Square of Proposition
Pictorials During Reporting
