Hart equivocates insofar as he fails to distinguish two very different theories that go under the “natural law” label. He also uses terms like “supernatural” and “metaphysical” as if they were interchangeable, or at least as if the differences between them were irrelevant to his argument. These ambiguities are essential to his case. When they are resolved, it becomes clear that with respect to both versions of natural law theory, Hart is attacking straw men and simply begging the question against them.
Also today, George Weigel describes the unique impossibility of the papacy:
To be pope is to take on a task that is, by precise theological definition, impossible. Like every other office in the Church, the papacy exists for the sake of holiness. The office, though, is a creature of time and space, and holiness is eternal. No one, not even a pope who is a saint, can fully satisfy the office’s demands. Yet the office, according to the Church’s faith, is of the will of God, and the office cannot fail, although the officeholder will always fall short of the mark. That distinction between the office and the man who holds it is a consolation to any pope.