(I'm going to take a page from our friend Fake Herzog and put this entry in the form of a letter.)
As you know, I've been a long-time fan of your blog Secondhand Smoke and often link to it and make my own comments on the stories you highlight there.
It's recently come home to me even more strongly just how important your place is in the world of philosophy and ethics. Here's the problem: The philosophical field of ethics seems to be irremediably corrupt, especially in bioethics. It is completely dominated by Peter Singer, Julian Savulescu, and their ilk, and the gatekeepers aren't allowing anything else. It is particularly difficult when a young philosopher might be inclined to accept human exceptionalism partly because of his own religious background; of course, religious premises are treated as entirely out of bounds.
I don't actually accept the proposition that religious premises are out of bounds. I believe that religious belief can be rationally grounded and, moreover, that it is crucial that our young Christian philosophers not be running about with "split minds," doing naturalist philosophy on weekdays and going to church on Sundays. We should integrate our worldview, and our well-supported religious beliefs should play a role in our ethical theory.
However, this doesn't negate the importance of the natural law, and as a sheer matter of psychological and practical fact, if Christian philosophers really believe that the only route to a humane ethics passes through propositions about the truth of Christianity, it is unfortunately all too likely that they will, at least for purposes of all discourse in their professional world, abandon humane ethics. This is especially true for young philosophers just getting started and under pressure to conform to Singer-esque assumptions. And it's still more true for those who have been, sad, sad to say, raised in our Western public school systems as "men without chests," in C.S. Lewis's words--men out of touch with the Tao, whose moral sensibilities have not been trained in basic humane principles about mankind and human nature.
This is where you come in. Though I imagine you wouldn't put it this way yourself, I see your role as that of restating the Natural Law for a post-Christian world. By starting with your principle of human exceptionalism, which as you point out can be supported by simple observation in a non-religious fashion, by assuming that there is such a thing as objective truth in ethics, and by not being intimidated by the zeitgeist, you are able to move past the anti-human and inhumane ethics of the contemporary philosophical world. You take your principles about the specialness of each human being, regardless of capacities, and you apply them to the particular, real-world cases. And as an outsider who does not depend for his bread and butter on the approval of the philosophical establishment, you are able to do this without fear or favor. This is an indispensible role.
To be honest, I would advise any young philosopher with any good moral intuitions not to specialize in ethics. The only exception to this advice might be if he could take his degree and then work in a traditional Catholic ethical milieu where natural law theory is well-respected, but how many people can do that? In the present economic and job market, it's not as though people thinking of going into philosophy can be as picky as all that in their school and job choices. But even if they are specializing in logic or epistemology or (especially) metaphysics, they are going to be surrounded by discussions that impinge upon the issue of human exceptionalism. If nothing else, such discussions will come up in the philosophy lounge when someone tries to tell them that they shouldn't be eating a chicken sandwich. And philosophers argue about everything.
So it's very important that there be a go-to place where those who have never been grounded in human exceptionalism can begin to get an idea of what a natural law ethics might look like in the real world and where those who have been so grounded can keep their weapons honed. For those purposes, I can't recommend Secondhand Smoke too highly.
Keep up the good work.