Are there Objective Moral Values in the world?

I posed the following question to @SecularOutpost on Twitter a few weeks ago:

@SecularOutpost layman’s questions: If “objective” is defined roughly as “having reality independent of the mind”, doesn’t the discussion of Objective Moral Values require explanations for 1) where OMVs would independently reside, absent the existence of minds, and 2) what mechanism(s) exist that make OMVs available to minds once minds do exist? Is that (part of) what’s required to make a sensible argument for OMVs?

He was kind enough to reply:

.@skepticali I think your analysis is good. The only part I might reject or edit would be the part about the mechanism(s) that make OMVs available to minds once minds do exist, since that blurs ontology with epistemology. It's possible that OMVs exist and we can know that fact, without knowing which OMVs exist.

My followup question:

@SecularOutpost how do we access OMVs? It *seems* to be culturally. If it’s truly objective, wouldn’t they be physical, in some sense?

His response:

.@skepticali I don't see why. 2+2=4 but I wouldn't call that physical. The answer to your question about access will depend on one's position about moral ontology. I.e., an ethical naturalist will have a different answer than an ethical non-naturalist.

I thanked him and went off into the woods for seven years of reflection and meditation. Or less.

After returning to civilization, I confronted my unrequited concern about the possibility of there being “independent reality” for objective moral values. I'm probably too unfamiliar with moral philosophy (or philosophy in general) to understand @SecularOutpost’s point that

“It's possible that OMVs exist and we can know that fact, without knowing which OMVs exist.”

I’m still troubled at how we can arrive at the actual OMVs that we say exist, and how a separate observer - maybe at a different time, place and culture - can arrive at those same actual OMVs. That we might not know which OMVs exist calls into question how it is that we could know they exist. I’m not saying that knowing OMVs exist in principal requires that we know which specific OMVs exist, but the lack of actual OMVs that we can independently arrive at - and verify - makes the argument that “OMVs exist” appear much weaker to me.

His tweet

“The answer to your question about access will depend on one's position about moral ontology.”

indicates that accessing the OMV’s is relative (”...will depend on...”), thus is not objective in the sense of “having reality independent of the mind”. I can restate this as

a Divine Command Theorist, an Ethical Naturalist, and an Ethical Non-Naturalist may all agree that OMVs exist, yet all three differ as to what they are.

This does not demonstrate to me that OMVs exist. It demonstrates that the three parties think they exist, and implies that they can each derive them repeatably using their individual principles and practices, but there is no guarantee that they can arrive at the same conclusions. @SecularOutpost's tweet seems to confirm this. Arriving at three potentially differing sets of OMVs would imply that two and maybe all three are not truly objective facts in the way that we think of gravity as being an objective fact. So I remain puzzled: “If there are Objective Moral Values in the world, how do we assure ourselves that they have reality independent of the mind?”

---

Postscript: I'll eventually be asking @SecularOutpost to review this and comment on it - but I think I'll let it breathe for a day.