I do think culture is an argument, and that was part of the way I was brought up. People at a social occasion in Ireland will start shouting and arguing. When the Yeats family lived in Bedford Park, they had to go round to the neighbours to say, 'You might think we are fighting, but this is the way we talk to each other.'

It's ironic that early on in the war with Afghanistan, the Americans and the British were saying, 'We recognise there must be a Palestinian state,' then they rapidly forgot about it. I think history will show that that kind of amnesia will come back to haunt you.

Is the biographer an artist who can and should exist on equal terms with the dramatist, fiction writer and poet? The short and robust answer is, 'Certainly not.'

I think ideas should be flying about and banging into each other. It is a kind of energy. If you occupy static positions, then things sort of ossify.