Early this past February some friends and I spent a weekend at a resort in the Pacific Northwest—at a February price, I'm happy to say—overlooking the islands of Puget Sound and dwarfed by the splendor of Mount Baker and the Cascades. In the lobby, inviting couches surrounded a massive stone fireplace. I came in from a walk along the beach early one morning ready to warm myself by the fire. Flames were flickering behind the screen.

I stood by the fire and waited for the warmth to soak in. And waited.

Eventually I realized that I was trying to warm myself at a gas-powered fireplace that was putting out less heat than a kitchen stove set to simmer. The logs burned but were not consumed. If I had been a Hebrew shepherd, I probably would have taken off my sandals and waited for a divine message.

But instead I remembered Albert Borgmann—probably the only philosopher in the world who has made a career of writing about fireplaces. Borgmann is one of those brilliant people whom almost no one has ever heard of, for some fairly good reasons. He teaches at the University of Montana, far from the chattering classes, and he writes, well, like a professor. His best-known book has a forgettable title—Technology and the Character of Contemporary Life: A Philosophical Inquiry—and between its covers is a dauntingly rigorous attempt, studded with terms like "deictic discourse," to understand the nature of technology. But Borgmann may be the most important unknown Christian philosopher of our day, because he understands what has happened to the hearth.

The fireplace, Borgmann reminds us, used to be the hearth—the center of a home both literally and figuratively. The Latin word for hearth is focus, and the activities of premodern homes in both Europe ...