I believe that you always have to believe. It's the only way; after all we both believe that we will do this exhibition. But I can't believe in God, as such, he's either too big or too small for me, and always incomprehensible, unbelievable.

But it is also untrue that I have nothing specific in mind. As with my landscapes: I see countless landscapes, photograph barely 1 in 100,000, and paint barely 1 in 100 of those that I photograph. I am therefore seeking something quite specific; from this I conclude that I know what I want.

Family photos, pictures of groups, those are truely wonderful. And they are just as good as the old masters, just as rich and just as beautifully composed (what does that mean anyway).

Above all, it's never blind chance: it's a chance that is always planned, but also always surprising. And I need it in order to carry on, in order to eradicate my mistakes, to destroy what I've worked out wrong, to introduce something different and disruptive. I'm often astonished to find how much better chance is than I am.

I wanted to make it as anonymous as a photo. But it was perhaps also the wish for perfection, the unapproachable, which then means loss of immediacy. Something is missing then, though; that is why I gave that up.

In 1981, I think, for the Kunsthalle in Düsseldorf. Before that I designed a mirror room for Kasper König's Westkunst show, but it was never built. All that exists is the design - four mirrors for one room.

A lot of different things had to come together over the years, accumulated experiences of a general and personal nature, before the idea and the decision were developed and then carried out.

Art is not a substitute religion: it is a religion (in the true sense of the word: 'binding back', 'binding' to the unknowable, transcending reason, transcendent being). But the church is no longer adequate as a means of affording experience of the transcendental, and of making religion real - and so art has been transformed from a means into the sole provider of religion: which means religion itself.

It was not possible for us to produce the same optimism and the same kind of humour or irony. Actually, it was not irony. Lichtenstein is not ironic but he does have a special kind of humour. That's how I could describe it: humour and optimism. For Polke and me, everything was more fragmented. But how it was broken up is hard to describe.