I. Matter and Spirit
The first and most obvious answer to the question of my title is that the church is that funny-looking building on the corner.
That’s not a wholly wrong answer. A building, like a church, has an identity. It gets its identity from its walls. Walls separate. Walls distinguish. Walls discriminate. They are like the lines around a geometrical figure or the borders around a country or the definition of a term. Walls are physical lines, borders, or definitions. They distinguish “inside” from “outside.”
The church must discriminate. It cannot be another word for “here comes everybody.” In order for anyone to be “in” it, somebody has to be “out” of it.
But everybody knows that the church is also something more than a building. What is that? If you ask that question to anyone who considers himself to be “outside” rather than “inside” the church, you might get a second obvious answer, which psychologists might call a “functional” definition rather than a “structural” definition. It’s something like: “It’s where you do religious stuff, like praying and reading the Bible and singing religious music and listening to sermons—the church is for churchy stuff.”
Of course the first answer is too concrete and the second answer is too vague (as well as being circular). But there is something true in both of them.