An argument for the duty to care about the well-being of others.

1. There is no duty to care about anyone's well-being.

2. So one can meet all of one's moral requirements, and still care about anyone's well-being.  From 1

3. But one who cares about no one's well being is a morally bad person.

4. So one who meets all of one's moral obligations can be a morally bad person.  2,3.

5. But for is 4 is false.

6. So 1 is false.