Ancient Light, your new novel, is about a 15-year-old boy having an affair with his best friend’s mother. You said on Radio 4 that writing sex into a novel is impossible.

The act is wonderful but writing about it is terrible, terrible. D H Lawrence tried to do it, with appalling results. It’s always either sentimental or terribly stern.

Is it something about the extreme subjectivity of the experience?

It’s the fantastical aspect about sex. We have to imagine we are clasping a goddess or a god in our arms, otherwise it won’t work. Afterwards, our rational selves have to realise that this is a human being. The erotic always tends to affection, love or negative things. You can’t write about fantasy without being ridiculous.

I would love to write a pornographic book – I think it’s a great challenge.

Do you read your own work?

No, I wouldn’t dare. When I have to do readings, I read with one eye closed. What am I going to discover here? Usually horrors.

But your prose style is very lyrical. Do you never read aloud when writing?

Oh, yes. I catch myself chanting these lines aloud. I don’t know I’m doing it – now and then I just hear it. It’s a very dangerous prose style to have.

Do you read the reviews you get?

About 20 years ago, I stopped eating meat. I was eating less and less and thought one day: “Just don’t eat it any more.” So I didn’t. At the same time, I found that I was reading less and less of the reviews. I thought: “Why not just stop?” It’s a wonderful sense of freedom. When I publish a book now I feel I’m in a hot-air balloon, in total silence, just drifting away. Then your friends ring you up and tell you about the bad ones.

Do you recognise playfulness in your novels?

Entirely. People take my work much too solemnly; seriously is fine by me. Life is tragic but it’s equally comic. A friend of mine called Ortwin de Graef publishes with the University of Nebraska Press and he was the one who uncovered the anti-Semitic newspaper articles by Paul de Man. If you look closely, [the fictional character] Fargo de Winter is an anagram of Ortwin de Graef. I was very pleased with that. And my friend used to be a punk, so this guy is a professor of post-punk studies.

Are these inside jokes scattered throughout?

Pedrigo Seagran in Ancient Light is an anagram of an Argentinian friend of mine. When I told him I was writing this book, he said, “Give me a walk-on part.” I should start charging. Would you like to be in my next novel? I’ve advertised Guinness quite a bit.

The tramp in Ancient Light, Trevor of Trinity, is like a character out of Dubliners.

He exists – he’s a straight description. I’ve always followed the congress of tramps.

Do you enjoy the Joycean comparisons?

It’s simply true that Dublin is a walking city. It’s infuriating in many ways. It’s very sad now because we’re all so poor, but it still has something of what it had when I first came from the provinces in the 1960s. All those clichéd things about Dublin are still there.

The novel is written with a strong, first-person voice. Are we meant to long for the interiority of the mother?

The point about Mrs Gray is that she lives on the surface. She’s not a thinker, not introspective. She’s so generous. I’m in love with her; I think she’s a wonderful creature. I don’t know how I created her. She must be my own mother.

Is this a preoccupation of our age – always trying to get below the surface?

Nietzsche says: on the surface, that’s where the real depth is. It’s true. All a work of art can do is present the surface. I can’t know the insides of people. I know very little about the inside of myself.

There’s a great deal of mirroring in the relationships. Do you map it out on paper?

I’m not doing it purposely. The older I get, the more I realise writing is a process of dreaming. I’ve learned to trust my dreaming self. The best stuff happens when you let the unplanned happen. No writer likes to admit that, because we like to imagine we’re in control, but actually we’re not. I think I’m less the writer than I’m the written.

“Ancient Light” is published by Viking (£16.99)