There have been studies concluding that most people mostly know people only within their own social class - although such a conclusion would hardly surprise anyone. I think there's evidence to suggest that it's even narrower - the great majority of friends of Ivy Leaguers, for instance, are Ivy Leaguers. This narrows the pool of people who can write fiction cutting across class boundaries that's informed by their own personal experience.

The twentieth century saw a professionalization of fiction writing, particularly in its second half and particularly in the Anglo-Saxon world - not so much mainland Europe, for example.

I had a tough childhood, yes. I was born in rural Bangladesh to parents who had had no education beyond high school. We moved to the UK where I grew up in poverty, in some of the worst conditions in a developed economy, before moving to the projects - heaven - and I went to unremarkable schools before going to university. My father was a bus conductor first and then a waiter, and my mother a seamstress.

Until I reached my late teens, there was not enough money for luxuries - a holiday, a car, or a computer. I learned how to program a computer, in fact, by reading a book. I used to write down programs in a notebook and a few years later when we were able to buy a computer, I typed in my programs to see if they worked. They did. I was lucky.

There are a variety of ways in which a wedge is driven between the reality of the world outside, the motion of atoms, and our conception of what is there. Some of it has to do with what we're told, some of it to do with sensibilities that might be described as cultural, some of it to do with habit, some to do with heuristics we, as Homo sapiens, invoke because we cannot do otherwise - to name just a few of the impediments.

The mathematical tilt remains basic to my epistemological perspective, my howling plea in the still of night for epistemic humility. Mathematics gave me that as, also, did the difficulty I had in talking to my parents. How proofs are conceived is unfathomable. Clearly, there are certain conditions in which the revelation takes place.

There was a period of a few months, however, when I had a dreadful physical pain. I had just started writing a particular section of the novel and was initially worried that it would affect my work. I was woken by awful nightmares; I saw several doctors, tests were performed, nothing came of them, and the medics were mystified.It was two days after I finished writing the section that the penny dropped. The pain had suddenly disappeared and so too had the nightmares. I'd got things muddled. The pain and the nightmares were both psychosomatic.