Categorical Logic and The Venn Test of Validity for Immediate Categorical Inferences

Exercise

Apply the Venn test of validity in order to determine whether the following categorical inferences are valid or invalid.

1. All S are P; therefore, all P are S
   
2. Some S are P; therefore, some P are S
   
3. Some S are P; therefore, some P are not S
   
4. Some S are P; therefore, all P are S
   
5. No S are P; therefore, no P are S
   
6. No P are S; therefore, some S are P
   
7. Some S are not P; therefore, some P are not S
   
8. All S are P; therefore some P are not S