Not Because Hume Didn't Try

The last post discussed John Finnis' claim that the Thomistic theory of desirable ends as the source of natural law, vis a vis the later opinion of Suarez that morals are rationally discernable and based on divine command.  It seems to have been the opinion of Finnis that somehow the desirable ends theory of Natural Law was impervious to the Hume's Dictum distinction between the way things are and the way things should be.  Of course, even Suarez was not really saying that Natural Law is simply doing things as they are currently done, he was saying that morals can be rationally inferred from nature, and there is a difference.  Estase sees a huge difference between the theory of Suarez and the theory that morality is somehow what is typically done.  What is typically done is customary, and Suarez would blush at the customary practices of the Jersey Shore.  What Suarez is getting at may be what Cicero implied in his works, a morality of realism based on what is naturally offensive, although Estase admits to little familiarity with Suarez.  Does Thomism survive Hume's Dictum?  If so, it's not because Hume didn't try.