But this biblical world picture is increasingly losing market share to what you might call the spiritual world picture, which keeps the theological outlines suggested by the manger scene — the divine is active in human affairs, every person is precious in God’s sight — but doesn’t sweat the details.

This is the world picture that red-staters get from Joel Osteen, blue-staters from Oprah, and everybody gets from our “God bless America” civic religion. It’s Christian-ish but syncretistic; adaptable, easygoing and egalitarian. It doesn’t care whether the angel really appeared to Mary: the important thing is that a spiritual version of that visitation could happen to anyone — including you.

Then, finally, there’s the secular world picture, relatively rare among the general public but dominant within the intelligentsia. This worldview keeps the horizontal message of the Christmas story but eliminates the vertical entirely. The stars and angels disappear: There is no God, no miracles, no incarnation. But the egalitarian message — the common person as the center of creation’s drama — remains intact, and with it the doctrines of liberty, fraternity and human rights.

As these world pictures jostle and compete, their strengths and weaknesses emerge. The biblical picture has the weight of tradition going for it, the glory of centuries of Western art, the richness of millenniums’ worth of theological speculation. But its specificity creates specific problems: how to remain loyal to biblical ethics in a commercial, sexually liberated society.