Further Thoughts On Atheism And Teleological Ethics

I've had a chance to think some more about my previous post and Daniel Fincke's reconciliation of atheism and teleology. Let's go back to this statement:

So, in this context, I am an atheistic virtue ethicist requiring no divine agency for the teleological dimensions of my ethics to make minimal sense and have minimal coherence. I am just describing purely naturalistically occurring patterns as universals or forms. I am saying that since humans’ very natures are constituted by a specific set of powers, fulfilling them is incumbent on humans as the beings that we are. It is irrational and a practical contradiction to destroy the very precondition of our own being (all things being equal). We have a rational imperative instead to flourish maximally powerfully according to the powers which constitute us ourselves.

My original criticism of this statement wasn't particularly well-developed, so I'd like to expand on it a little more.

I agree that Daniel has described how an atheist might rationally be ends-directed/ends-oriented. However, as with my criticism of "goodness as effectiveness", I think the primary problem is that the rational pursuit of "maximal flourishing" doesn't reach far enough/isn't strong enough to form the basis of anything we'd recognize as an ethical system. Daniel has based his defense of ends-oriented behavior on the idea that instrumentally rational individuals have ample reason to further their personal development:

So, we have these powers, they constitute our very being. It is irrational for us to try to destroy these powers (all things being equal) since they are us ourselves and they are the precondition of every conceivable good we could achieve.

Agreed. However, it does not follow from there that individuals have a rational imperative to value the maximal flourishing of their fellow sentient beings. Coincidentally, I'm currently reading Gerald Gaus' The Order Of Public Reason, which spends a non-trivial amount of time discussing whether instrumentally rational agents are capable of reasoning themselves into this type of regard for others. His conclusion, which I've zero cause to dispute, is that they can't:

If social morality allows us to better achieve our ends, it must follow that individuals concerned only with achieving their ends could reason their way to it. This elegant proposal has failed. Gauthier and others tried to implement it by revising the very concept of instrumental rationality, but in so doing the elegance and plausibility of their solutions was undermined. Those who sought to achieve it without abandoning the core elements of the instrumental idea had a variety of interesting ideas, but more sophisticated analysis shows that they are unable to support large-scale human cooperation. Instrumentalism has proposed a problem that it cannot solve in its own terms. As we are about to see, "deontological," rule-based reasoning that does not derive from instrumental reasoning - the bete noir of the instrumentalists - is requried to solve the problem that they posed. (p. 100)

So it seems to me that Daniel has only provided part of the solution: He's shown why an atheist can care about emself, but hasn't shown why an atheist should care about others. Absent that showing I don't think he can claim to have a system of ethics that is coherent, atheistic, and teleological.