In a sense these are questions that most people ask themselves to some extent. They become philosophical when asked with a persistence and rigour that pushes past conventional or evasive answers. It's nothing to do with acquiring a technical facility in an academic discipline.

Perhaps this is an area where every generation starts from scratch. Although the crisis of the First World War inaugurated an especially strong period of disillusion with regard to the optimism of the previous age, the pattern has repeated itself in many ways in more recent times, e.g., the loss of faith in politics as a means of advancing human well-being. And perhaps this also has to do with basic elements in growing up.

At a theoretical level, I think a naturalist approach to religion is just asking questions I'm not interested in. They're perfectly legitimate in their own terms, but they don't address the actual experience of how one or other aspect of religion becomes existentially meaningful to us in our actual lives. The fact that we ourselves are the subject of investigation makes all the difference.

Schleiermacher, however, starts by attempting to find what he takes to be a basic element of the human condition as such, namely, that we did not invent ourselves but find ourselves born into a life and a world that precedes us in manifold ways.

I'm not sure if Cupitt himself still uses this term, but it's useful in suggesting that, actually, there are more choices than the choice between nihilism and faith. In fact, the issue may not be faith as such but the fact that for millennia, Christianity has buttressed itself with a particular kind of metaphysics that has now seemingly reached the end of its life-span. But perhaps Buddhist metaphysics could provide an alternative here - or, at least, offer a direction of travel.

But why should a religious person be interested in a work like Heidegger's that many regard as the epitome of nihilism? For a start, because Heidegger forces us in a way that few philosophers do to really think through the seriousness and all-encompassing nature of our mortality.

Now, as at the beginning of the 19th century, there is a certain discovery of Eckhart and related figures. There are questions as to how far our Eckhart accords with the real medieval teacher of that name, but there are certainly images in his work that help us work our way past several of the aporia with which we're confronted in our attempts to think about God.