I was intrigued by your discussion of Pathology epistemology, but the more I think about it the more I am disturbed. Your Roman Catholic metaphor, I think, drew me to my disturbing conclusion. I would like to point out a couple of things:
Your well-written rant does point out the absurdity of being held to some impossible standard by the courts or public opinion or whatever, when the "experts" often don't agree or don't even justify their position, but again, this absurdity does not indict the process so much as it does the epistemology of those who render judgement on us. Some people have the mistaken impression (I think it's a mistake, anyway), that "science" means some process by which everything is exact and "human error" is completely absent. If human error is ever felt to play a significant role, the tendency is to throw up one's hands and say "hey, don't ask me, it's an 'art.'"
I don't buy this opinion. First of all, all of science requires observation, even if it's as elementary as counting ticks on a geiger counter. As such, all of science involves "subjective" determinations. The essence of the process, in my view, is that science is grounded in aristotelian logic. A is A, A cannot be A and not A at the same time. Most scientific endeavors are difficult because it takes a long time and much work to reduce a problem to a simple question such as "A or not A" (mitotic figures or no mitotic figures).
Difficult diagnoses are not indictments of the science of Pathology, but in my optimistic view are evidence of how far we have come in diagnosing human disease; unfortunately, we are often lead to try to answer questions which are of a degree of resolution which we cannot logically expect to solve. We as pathologists may be responsible for this, or maybe we are too driven by public expectation or fear of litigation or whatever, but the fact remains that the discipline must be held high as a scientific one or we have no chance at all.