I didn't write anything until I was well over 30.

But who knows their own child? You know bits - certain predictable reactions, a handful of familiar qualities. The rest is impenetrable. And quite right too. You give birth to them. You do not design them.

The idea that memory is linear is nonsense. What we have in our heads is a collection of frames. As to time itself-can it be linear when all these snatches of other presents exist at once in your mind? A very elusive and tricky concept, time.

Equally, we require a collective past - hence the endless reinterpretations of history, frequently to suit the perceptions of the present.

The present hardly exists, after all-it becomes the past even as it happens. A tricky medium, time - and central to the concerns of fiction.

Giving presents is one of the most possessive things we do, did you realize that? It's the way we keep a hold on other people. Plant ourselves in their lives.

We open our mouths and out flow words whose ancestries we do not even know. We are walking lexicons. In a single sentence of idle chatter we preserve Latin, Anglo-Saxon, Norse: we carry a museum inside our heads, each day we commemorate peoples of whom we have never heard.