--Robert M. Persig, Lila: An Inquiry into Morals.
In other words, empiricists have to re-invent the wheel a lot.
What I question is, do we have to view such fields as unverifiable? In the case of art, the content of the communication is received through the senses - watching a dancer, listening to music, even touching a sculpture. In the case of morality it seems that the claims of a given moral can be tested in our own sense experience, or that of others around us (at some level we have to have criteria for accepting some of the sense experience of others or we really do have to not only reinvent the wheel, but do molecular examination of each bite of food we take to make sure it is indeed food [not to mention that we would have to develop such examination methods entirely ourselves]). Metaphysics that claim to merely be imaginative speculation would be unverifiable, but it seems most metaphysics are based on ties (however tenuous) to sense experience--so the validity of the ties is what comes into question. In the case of religion, most religious teachings are in texts which we experience ourselves and can test aspects of with sense experience (to determine whether the authors are trustworthy), and most of those texts claim to be the result of the writer's sense experience of the deity, or extrapolations from previous writers' experiences. I'm not sure if Mohamed claimed his writing to be revealed to him by God (an instance of the former) or, rather, written through him by God (which, since it lacks the humans sense experience, would be unverifiable if we don't allow God's sense experience as valid for argument). In the case of authors like Moses, Isaiah and Matthew, they claim to be writing the result of their sense experience encounters with God. In the case of a writer like Paul, or the author of Ecclesiastes, they generally claim to be explaining or applying the work of previous writers, or that which is obvious from experience. Paul does develop new things, but he generally does so by inference from previous writings, not by just asserting "thus sayeth the Lord."