Logic Syllogisms

Category

a class of something; classifying logic as something

Deduction

premise based logic, using premise to come to a conclusion

A-Claim

All x are y

E-Claim

No x are y

I-Claim

Some X are Y

O-Claim

Some X are not Y

Subject term

The noun or noun phrase that refers to the first category mentioned in a standard-form categorical claim.

Predicate

The noun or noun phrase that refers to the second category mentioned in a standard-form categorical claim.

Noun phrase

just subject or predicate that goes as phrase

Venn Diagram

venndriagram for testng truth

Translation

translating claim from one to another

Mass nouns

example of

Square of Opposition

A table of the logical relationships between two categorical claims that have the same subject categories and the same predicate categories in the same order.

Contrary

A and E, they can both be false, but bot cannot be true

Subcontrary I and O

Two non-universal categorical claims that can both be true at the same time but cannot both be false at the same time.

Contradictory A/O and E/I

never the same true value

Contraposition:

The statement that results from switching the places of the subject and predicate terms in a categorical statement and replacing both terms with complementary terms. The contrapositive of “all Baptists are Christians” is “all non-Christians are non-Baptists.”

Syllogism/Categorical Syllogism

A two-premise deductive argument in which every claim is categorical and each of three terms appears in two of the claims

Major term/premise

predicate of the conclusion

Minor term/premise

subject term of conclusion

Middle term/premise

only appears in the middle

The three rules

rules for validty

Four main symbols

negation-not, conjuction-and/while, disjunction-or, conjunction-if