One of my students suggested that the corpse represents the "noble war dead" always invoked in political oratory to this day. The dead are always summoned to bear witness to some national cause. My student believes that what Goya is saying is that ultimately the dead have nothing to say to us. They have no answers for us. I like this idea.
While Goya painted lots of religious work on commission, he was not a believer. He despised the Spanish Church as a bastion of superstition, corruption, and reaction. In his private prints and paintings, he savaged it. What I think he suggests in this print is that the traditional language of religion is now forever broken, that this new world of modernity has no reliable precedents to guide it, that institutional religion is too busy preserving its identity to have anything meaningful to say. And yet, Goya shows us that those original stirrings, that ancient fear and reverence for the dead, those dreams and powerful intimations that gave rise to religion in the first place, are still very much with us, looking for new forms in which to manifest themselves.
Goya gives us one of the greatest and most powerful images of doubt in art.