We discussed Utilitarianism. And, we discussed necessary and sufficient conditions in greater detail. We learned that it is easy to come up with a counter-example. And, hopefully, we learned that it is useful to analyze our intuitions. We then said that for the next several days we would be interested in Normative Ethics .
Normative ethicists are interested in finding a criterion for morally right action.
As an example we discussed a criterion for dog-hood. A criterion for dog-hood should satisfy two things. It should tell us what is sufficient for being a dog, and it should tell us what is necessary for being a dog. According to GR, a masochist would be justified in hurting other people because he likes to be hurt himself. I leave it up to you to decide whether the counterexample works or not.