All cyclops are one-eyed. Some trolls are not one-eyed. Therefore, some trolls are not cyclops. This syllogism is:
A) Valid
B) Invalid; affirming the consequent
C) Invalid; denying the antecedent
D) Invalid; undistributed middle term
E) Sound

Question

Quizplus · Accepted Answer

The syllogism is valid as it follows the pattern of the valid syllogism called "I-O". The premise "All cyclops are one-eyed" is an "I" statement, and the premise "Some trolls are not one-eyed" is an "O" statement. When we put these together, we get the conclusion "Some trolls are not cyclops," which is also an "O" statement. Therefore, the syllogism is valid.

All Cyclops Are One-Eyed