Hilary Mantel: In the ideal world, all writers would have a Catholic childhood, or belong to some other religion which does the equivalent for you. Because Catholicism tells you at a very early age the world is not what you see; that beyond everything you see, and the appearance – or the accidents as they're known – there is another reality, and it is a far more important reality. So it's like running in the imagination. I think that this was the whole point for me – that from my earliest years I believed the world to have an overt face and a hidden face, and behind every cause another cause, and behind every explanation another explanation, which is perhaps of quite a different order. And if you cease to believe in Catholic doctrine it doesn't mean that you lose that; you still regard the world as ineffable and mysterious and as something which perhaps in the end can't quite be added up. It could be summed up as saying "all is not as it seems", and of course that's the first thing Catholicism tells you. And then it just runs through everything you write and everything you touch, really. Plus, it's good to have something to rebel against.
After the writing's finished, how do you judge the quality of your work?
Peter Porter: I'm not at all confident about the quality of what I do, and I suffer like all people do, I think, who are writers, an intense disappointment – not at the reception of what I've written, but at my own inability to bring off what I want to bring off. Auden in his introduction to his Collected Poems(well, the first one of his collected poems), said in a writer's work there are usually four categories – he loved categorising things. First, sheer rubbish which he greatly regrets ever having done. Second, poems he's got nothing against except they're not very important; they're not very good but, you know, he doesn't hate them. Third, the saddest of all, the fair notion, fatally injured. And then the last one, the handful of poems he's truly grateful for, which if he were to publish would make his work seem dangerously slim, and vitiated.
So why write?
Hilary Mantel: It's always worried me, is writing a way of life or is it a way of not living, is it essentially a second-hand pursuit? I think it probably worries all writers, but then they say the onlooker sees most of the game, so that's the virtue of it.
Peter Porter: Literature is a sort of keeping going while the various destinies all around about you are being enacted. It's a way, I think, of coping with time. We don't seem to live very long, and yet on the other hand 24 hours can be a tremendously big burden.
The Guardian, Saturday 26 March 2011