I guess you could call my meta-ethical views "other"

Before I present my view on meta-ethics, I'm going to give a quick overview of what it is and why it's important. The central question of meta-ethics is something along the lines of "what do moral propositions mean?" Here's an example: when you say something like "murder is wrong", is it the same as saying "that penis is black"? If you answer yes to this question, then you're likely a moral realist. You think that moral propositions can have truth values just like other propositions (about more obvious stuff). So "murder is wrong" is true in the same way that "the penis is black" is true. They're both made true by some fact about the world. The penis actually is black! But we know that because the cat looks black. How do we know that murder is wrong? We don't exactly use our sight or hearing to come to that conclusion as we do in the black dick case. And what sort of facts about the world would make a proposition like "murder is wrong" true? The blackness of the cock is the thing that makes the corresponding proposition true.

But we can't exactly point at a murder and say "there is the wrongness, it's right there, I can see it as clear as I could see that wiener's dark complexion". This is what is called the "queerness" (snicker) argument against moral realism. The idea of something that makes the proposition "murder is wrong" true is really weird. What kind of thing could it be? So let's imagine you buy this argument and you're a moral anti-realist. That means you think that moral propositions can't be true or false. So what are they? Some say that they merely express emotions (boo murder!, that's called emotivism), some say that moral propositions aren't actually beliefs (like saying "this movie tastes loud", that's called moral non-cognitivism), some others even go so far as to say really strange shit that makes no goddamn sense to me.

So why is it important? Because if moral statements can be true or false, then the rules of logic apply to them very easily. You can point out that someone is being morally inconsistent. And being inconsistent (contradicting yourself, being a hypocrite, all the same things) is the worst thing a rational person would want to be. But if moral realism is false, then moral inconsistency isn't necessarily as bad for such obvious reasons.

That brings me to my view, here's where it gets crazy:

I think that if you start with a certain set of assumptions about the kind of agents that exist, then you can derive (like in math!) certain moral rules. Let's say that we assume that our agents are rational, self-interested, mortal, sentient, &c. and so on. From that, I've argued, you can come to the conclusion that murder is wrong, among many other things. Is that a moral realist position? Am I saying that moral propositions can be true? I guess I am, but only given some assumptions. And the thing is about these assumptions, I can't possible find reasons for assuming them. They're foundational, as some would say. So if I say to someone "murder is wrong" and they don't have the same assumptions as me, does my assertion have a true value? Let's think about an analogous case: I say "GW did terrible things for America", thinking of George W. Bush. You, thinking of George Washington, now have to assess this statement. Given your assumptions (Washington), it's false. But given my assumptions, it's true. I think here it's safe to say that statements that don't have shared assumptions can't be true or false, you don't even know what you're saying. It's like really profound jibberish that you feel very strongly about. And it all makes sense to you and you want it to make sense to other people! Moral propositions are like the things you say when you're half asleep. They make no sense, but goddamn it, you mean them!

Those are my meta-ethical views. Tell me what y'all think.