Are You Playing the Fool?
- All A are B
- No A are B
- Some A are B
- Some A are not B
Unsound Categorical Syllogisms (another example)
Rules for Syllogisms
- Syllogisms with two negative premises are invalid
- Syllogisms with two positive premises must have a positive conclusion.
- Syllogisms with a negative and a positive premise must have a negative conclusion.
- Syllogisms have exactly 3 terms.
- The term that occurs in both premises must be modified by the words all or none at least once.
- A term that is modified by all or none in the conclusion must be modified by all or none in one of the premises.