I keep going back to the cat and mammal examples.

1. ex. Tom is not a mammal. We know for sure then that Tom is not a cat because being a mammal is 100% required for being a cat.

2. ex. Tom is a cat. We know for sure that Tom is also a mammal because being a cat is sufficient enough info to know Tom is 100% a mammal.

3. ex. Tom is a mammal. Well that doesnt guarantee anything because Tom could still be a human or dog or whatever other mammal.

4. ex. Tom is not a cat. Again, doesnt guarantee anything cause Tom could still be another type of mammal.