This is great. I love your persistence. The answer, I think, is that this sentence:
We are moral agents, i.e., moral agents are the kind of creatures that do X whether they want to or not.
is not a claim about a “naturalistic” property of humans. “Moral agency” is not a natural, i.e., biological or found in nature, kind of property that can be established by natural or scientific means. It is not that kind of “is” that the ought can not be derived from. In G.E. Moore’s term, it is a “supersensible” property, not a “natural” one.
Again, the argument could be made that “is” functions, in this case, to indicate something other than a “natural” property, so the naturalistic fallacy would not apply. To say, “Joe is a moral agent,” cannot be taken to indicate some property of Joe than can be determined naturalistically or evidentially as his hair colour or blood type.
It seems, though that Moore thought his ”cannot derive an ought from an is" did extend beyond naturalistic statements to even “supersensible” ones. A good article on the issue is here:
plato.stanford.edu/entries/moral-non-naturalism/#NatFal
Whoa boy, I’m hoping this is not become some kind of transubstantiation thing (i.e., the bread isn’t the Body of Christ, but in “another” sense, it is).
I’m going to have to really read up on what a “supersensible” property is and isn’t, and how it differs from a natural property.
With that assignment in hand, I leave a few words in closing:
I’m going to disregard the entire idea of “oughts” and just look at some cold, hard logic here.
A and ~A cannot be simultaneously true. At the very least, A and ~A cannot be understood by our human minds.
We utilize the basic laws of logic by default, as they are quite necessary for our continued existence. I cannot have eaten today
and not eaten, when I’m driving down the highway, there is either another car that I must slow down so as not to hit
or there is not. This is the fundamental “is” of the universe.
So it seems to me that if we’re going to have any moral principles at all, they must be universal and consistent. We cannot say murder is both A and ~A (moral and immoral) depending on the person, place or time. Neither with theft, nor adultery, nor rape and so on.
With regards to the “ought”, for now I look at it this way. As you suggested, most men
do want to do “right”, and all things considered, there’s a pretty broad consensus as to
what is “right.” We disagree, albeit rarely, with regards to the definition or murder, theft, rape, etc. but everywhere, in every culture, these things are considered criminal.
So while finding the “ought” is a fun mental exercise, it hardly seems necessary on a practical level. Those convinced that there is such a thing as a moral truth do not need such convincing.
Meanwhile the few who are genuinely doubtful that there exist moral truths, well, those people are largely not worth the time. I’m not going to sit there and discuss the finer points of morality with a mugger.
So, in the end, almost all of us accept moral truths, but we have the question of how to define them.
Unfortunately, I don’t think the existence of God makes this any easier (nor any harder, but not any easier) because if we’re going to say that something is good because God deems it to be such, because good is in God’s nature, then we still have the is/ought problem.