It would take weeks to catalog all the problem in Paul Manata's, um, "takedown" of the Ethical Atheist in this post. Let's just get a taste for the confusion with this paragraph from the post:
iv) The cash value of (iii) is that there is a sense in which we can say that atheists cannot be moral. Now, certainly we don't mean that they can't (or don't) follow moral norms (but there are some norms that they do not follow, e.g., praying), we mean that they cannot meet all the requirements needed for us to judge them as "good" people. Thus in a minimalist sense, atheists can be moral. That is, they can follow (many of) the right standards. Of course this was recognized far before these contemporary debates (cf. Romans ch. 2). My more qualified sense is something that the atheist can accept since it depends on theism being true. Thus if theism is true, the atheist cannot be "good" where "good" means more than merely following your duty, or even exhibiting a couple of good character traits (though this would have to be defined biblically, and so it would be hard for the atheist to really have these. Perhaps he can have them in a minimal way. I leave that open for discussion). But, I take it that in this debate, and the sense the Ethical Atheist meant it in, the claim that "atheists can't be moral" is usually intended to connote the idea that atheists cannot adhere to some basic, fundamental, paradigm cases of morality according to a normative model. That is, atheists can refrain from murdering, lying, stealing, etc. (Of course, even here, qualification could be made, for there is much more to following those commands than ordinarily thought. But again, I'm speaking in a very minimalist way. Perhaps a way in which the atheist can accept as what constitutes following moral precepts.)(emphasis mine)
Got that? The bolded sentence is the jewel in the mix, here. Paul is simply decimating when he lays out his arguments with "if theism is true". Here, we are treated to the observation that IF theism is true, and THEISTs get to define all the terms ("moral", "good", etc.), well, then there is a sense in which those atheist just can't qualify as "good" or "moral". Chew on that for a moment to fully savor its depth and wisdom.
Let's turn that around for a moment. Would Paul say this?:
"If atheism is true, the theist cannot be good where good means more than following your duty, or exhibiting a couple of good character traits (though these would have to be defined rationally, so it would be very hard for the theist to have even these)."
Well, duh, Paul. If you begin by assuming the primary question (a/theism?), then let the "winner" define the criteria, the "winner" can fashion things any way they want (note how Paul suggest that 'theism' would require Biblical justification for good character traits... 'theism' being a kind of unconscious euphemism for his brand of Calvinism).
Earlier in the post, Paul dismisses the argument the Ethical Atheist is adressing -- "atheists can't be moral" -- as a "canard"; no one actually claims that, suggests Paul. But he can't hold off more than a paragraph or two before launching into just that argument.... "if theism is true", of course.
It's unfortunate that Paul fails so completely to grasp what is being argued by the Ethical Atheist. He has a quite a challenge trying to paint a veneer of coherence over his Calvinism, just on its own terms, but this post is an example of the kind of mental train wreck that comes out of adopting the "worldview" he's chosen. He cannot proceed, of course, from the agnostic point of rational inquiry, neither assuming theism true nor assuming it false. His game's up as soon as he allows that kind of abstraction. So he's bound to thinking about atheism through his lens of presuppositionalist Calvinism, which produces things like... well, go read the post.
You'll see what I mean.