What if there is no diminishing pluralism—what if on the contrary, it increases?

I don't regard it as ever problematic. It can be a useful test of the progress made by the advocates of a concept. Quantum theory was first proposed only a little over a century ago, so the scientific community still disagrees about how to understand it, but not as much as it used to. As progress continues, I would expect some continued diminishing of that disagreement.

Problematic vs. unproblematic pluralism.

So, pluralism simpliciter indicates very little.

I'd say that depends on what the divergent opinions are about and on the context in which the subject arises.

Agreed, but where is the line of demarcation?

Demarcation between what and what?

Agreed, but where is the line of demarcation? For example, if one requires a way to empirically differentiate pluralism, now, in order for the pluralism to be acceptable, then one will be condemning much of the pluralism visible at WP: Interpretations of quantum mechanics (possible exception: psi-epistemic vs. psi-ontic). Furthermore, there are ways to empirically differentiate conceptions of sin, as I pointed out. And so, there are multiple things just plain wrong about the following:

DS: Sin is a theological concept. There is nothing for me to understand except what Christians say about it, and what Christians say about it is all over the place.

1. The idea that sin is just a theological concept is erroneous, unless the very same phrasing can be made in a different realm: "F = ma is a physical concept. There is nothing for me to understand except what physicists say about it..." I doubt you would find this acceptable.

2. Given the context, your "all over the place" is surely meant to indicate that one's conception of sin is unconstrained by reality. In a way this may be true (but also true of interpretations of QM); philosophy which examines this is Underdetermination of Scientific Theory.

So, pluralism simpliciter indicates very little.

I'd say that depends on what the divergent opinions are about and on the context in which the subject arises.

Interesting; I have not observed this. Then again, I've seen plenty of pluralism in the sciences—all the sciences. So, pluralism simpliciter indicates very little. Actually, perhaps I have seen atheists drop out of a conversation when pluralism was presented. I'll have to pay more attention in the future.

It seemed to function as a conversation-stopper.

Stopping conversation was not my intention, but I have noticed that Christians often do either stop talking or change the subject whenever they're reminded that lots of other Christians disagree with them (as well as one another) about whatever point they're trying to make.

Suffice it to say that I have no idea why you said what you did, to Paul F. It seemed to function as a conversation-stopper.