Version 3 of the document.
Unfortunately, for some reason I can no longer update this post using the blogger program. Luckily, I can get around this problem by posting any modifications as PDFs. So the PDF containing my post is given here. Enjoy. [And thanks to Rayndeon for advising that I to do this.]
The abridged argument map which summarizes each section's argument is given here.
The abridged map is a bit outdated and the post is incomplete, much of it still in stream-of-consciousness form. It's also long. Very long. Treat as a working draft. I expect to be working on this for at least the rest of the year, and will incorporate further rebuttals to arguments against moral naturalism as time goes on.
When I first posted this I was, in part, trying to present the strongest version of atheistic moral realism (i.e. moral realism that did not require nor imply God's existence) I could to counter theistic claims regarding morality implying God's existence. I wanted to show proponents of these claims what a plausible meta-ethical view looked like, as opposed to the wildly implausible views they were offering. In the process, however, I argued myself out of moral nihilism and into accepting the very moral realist position I laid out! "Hooray!," I thought. "I just constructed a novel position." I should have known better; there's nothing new under the Sun. I soon realized (sometime in early to mid September 2012) that the position I defended was just one variety of Cornell realism.
This was both affirming and distressing. It was affirming because I argued for Cornell realism based mostly on arguments I constructed on my own, as opposed to just following along with another philosopher's views. I had heard of Cornell realism and read a few essays from Brink, Boyd, and Sturgeon in undergrad. But those essays never convinced me to reject moral nihilism and so I mostly forgot about them. It's nice to see things come full-circle, with me now advocating my own version of Cornell realism. Now on to why this was distressing: my view isn't completely novel. This means that somewhere in the world, Boyd, Sturgeon, and Brink are saying "U MAD BRO?" to all the atheistic moral naturalists who, like me, ended up arguing for the position that trio advocated in the late 80's and early 90's, and which they still continue to defend to this day. But that's alright. I'm not going to reject a position I agree with regardless of whether it's popular, reviled, old, or new.
So I received my copy of Brink's "Moral Realism and the Foundation of Ethics" in the last week of September 2012. I can already see a number of places where he and I disagree, but we'll see where things go from here.