Ross Douthat writes that there are three spiritual worldviews in America today. You might call them hard-core biblical, soft-core spiritual, and secular. Unsurprisingly, he's bearish on the secular worldview:
The secular picture, meanwhile, seems to have the rigor of the scientific method behind it. But it actually suffers from a deeper intellectual incoherence than either of its rivals, because its cosmology does not harmonize at all with its moral picture.
In essence, it proposes a purely physical and purposeless universe, inhabited by evolutionary accidents whose sense of self is probably illusory. And yet it then continues to insist on moral and political absolutes with all the vigor of a 17th-century New England preacher....So there are two interesting religious questions....The second is whether the intelligentsia’s fusion of scientific materialism and liberal egalitarianism — the crèche without the star, the shepherds’ importance without the angels’ blessing — will eventually crack up and give way to something new.
The cracks are visible, in philosophy and science alike. But the alternative is not. One can imagine possibilities: a deist revival or a pantheist turn, a new respect for biblical religion, a rebirth of the 20th century’s utopianism and will-to-power cruelty.
I'm willing to concede Douthat's main point: the secular scientific worldview doesn't provide much of a philosophical basis for a moral system. I don't think it's quite as barren of metaphysical guidance as he suggests, but still, he has a point.
But here's what I've never understood about the kind of argument Douthat is making: it's not as if secular ethics is a modern invention. Aristotle's ethics were fundamentally secular, and were appropriated by the Church only long after his death. More recently, we have the example of plenty of modern, secular states in Europe and elsewhere, which appear to effortlessly practice an ethics every bit as praiseworthy as that of more religious states. On a personal level, there's never been the slightest evidence that religious believers behave any better on average than the nonreligious.
None of this is new. Sure, in some abstract way, it's not possible for me to justify my own sense of ethics all the way down to its ultimate core, but in real life that's something I never even think about. In a practical, human sense, my sense of morality is every bit as strong as Douthat's. He might attribute this to God and I might attribute it to the evolution of the human brain and human society, but either way there's no inherent tension in the secular view simply because it lacks an ultimate metaphysical justification. It's just not something that affects most of us even slightly. Douthat is imagining cracks that aren't there.
At a broader level, you might still wonder whether religious underpinnings for morality are more effective at producing an ethical society. Again, though, where's the evidence? You can enforce morality by threatening people with hellfire, or you can enforce it by threatening them with jail time. Both work pretty well—though I'd note that religious societies tend to partake liberally of secular punishments too. Hellfire apparently has its limits.
Secular ethics isn't some newfangled 20th-century experiment that's falling apart at the seams and must inevitably be replaced with a deist revival or the return of Pol Pot. It's millennia old, and doing just fine. It's true that sex and gender roles have changed dramatically over the past century, and that's certainly produced plenty of tension and discomfort along the way. And for all too many devout Christians, that seems to be the real wellspring of their discontent: not secularism per se, but changing sexual mores in particular, which produces a foreboding sense that society is inevitably sinking into moral degeneracy. Christian apologists would do well to keep the two subjects separate.