Consider the following argument: All baboons are trapeze artists.
Some trapeze artists are not hairy-legged.
Therefore, some baboons are not hairy-legged.
1. Even if the premises were true, it is possible that all the trapeze artists who are not hairy-legged are humans (or shaven chimpanzees, or bald gorillas), and none of the hairless artists are baboons.
2. This has the same argument form as the invalid argument: All cats are mammals;
- Some mammals are not felines;
- Therefore, some cats are not felines.