I want to explore here the constitution in modernity of what I shall call “closed” or “horizontal” worlds. I mean by this shapes of our “world” in Heidegger's sense which leave no place for the “vertical” or “transcendent,” but which in one way or another close these off, render them inaccessible, or even unthinkable.

This will be a way of making sense of a remarkable historical fact, which strikes us as soon as we take a certain distance, that, say five hundred years ago in our Western civilization, non-belief in God was close to unthinkable for the vast majority; whereas today this is not at all the case. One might be tempted to say that in certain milieux, the reverse has become the case, that belief is unthinkable. But this already concedes the lack of symmetry. It is truer to say that in our world, a whole gamut of positions, from the most militant atheism to the most orthodox traditional theisms, passing through every possible position on the way, is represented and defended somewhere in our society. Something like the unthinkability of some of these positions can be experienced in certain milieux, but what is ruled out will vary from context to context. An atheist in the Bible belt has trouble being understood, as often (in a rather different way) do believing Christians in certain reaches of the academy.