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Logic: deductive validity

possible case in which the premises hold true when the conclusion is false - the actual case.

This is easier to grasp by looking at some examples. The following are, respectively, examples of cases 1-5 given above; the 'T's and 'F's in parentheses to the right of each premise or conclusion indicates its actual truth or falsity, as the case may be:

P2)

Janet Baker is an opera singer. All opera singers are musicians.

(T) (T)

C)

Janet Baker is a musician.

P2)

Janet Baker is a baritone. All baritones are Italians.

(F) (F)

C)

Janet Baker is an Italian.

P2)

Janet Baker is a baritone. All baritones are English.

(F) (F)

C)

Janet Baker is English.

P2)

Janet Baker is a soprano. All sopranos are English.

(T) (F)

C)

Janet Baker is English.

P2)

Janet Baker is a soprano. All sopranos are Italians.

(T) (F)

C)

Janet Baker is an Italian.

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