Exclusive premises

For more information, see the Wikipedia article:

Exclusive premises

The fallacy of exclusive premises is a premise that comes to an affirmative conclusion when both of its premises are exclusionary (Negative).

Logical Form A

• P1: No X are Y
• P2: Some Y are NOT Z
• C: Some Z are NOT X

Logical Form B

• P1: No X are Y
• P2: No Y are Z
• C: No Z are X

Example 1

• P1: No Salmon are Canadian
• P2: Some Canadians are NOT Muslim
• C: Some Muslims are NOT Salmon

Example 2

• P1: No Animals are Toasters
• P2: No Toasters are Cats
• C: No Cats are Animals

Just because the conclusion may be true, ie. in the real world, this does not mean the argument is valid.

You may just have been lucky.

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