1. 5 Categorical Syllogisms
5.3 Rules and Fallacies

2. Categorical Syllogisms
There are 5 rules for and 5 corresponding fallacies that beset categorical syllogisms. They are:
The middle term must be distributed at least once (fallacy: Undistributed Middle)
All Tacos are Messy things
All Sandwiches are Messy things
All Sandwiches are Tacos
All Messy things are Fun
All Tacos are Fun
If a term is distributed in the conclusion, it must be distributed in a premise (fallacies: illicit major or illicit minor)
Two negative premises are not allowed (fallacy: Exclusive premises)
A negative premise requires a negative conclusion, and a negative conclusion requires a negative premise (fallacies: Drawing an affirmative conclusion from a negative premise or Drawing a negative conclusion from affirmative premises)
If both premises are universal, the conclusion cannot be particular (fallacy: existential fallacy) T T S F M M

3. Testing Syllogisms by Rule
Construct these syllogisms and test: IAI-2 EIO-1 IEO-1 EOO-4 AII-3 AAI-4