The reason that the most ancient texts we have inherited - such as the Epic of Gilgamesh from Sumerian civilisation 5,000 years ago - still speak to us so vividly is that those works ask why questions - some of the very big ones: when the wild man Enkidu dies, Gilgamesh is struck down with unbearable grief, why death, he cries out in protest, and then embarks on a journey to learn.

A great work of art like this beautiful building we are fortunate enough to be in tonight was made layer by layer detail by detail to stimulate us to identify with the mysteries it embodies, to feel with the sufferings and the glories of the characters in the stories it tells, and through that emotional engagement to think about existence and its significance: a cathedral is a library and a picture gallery and it unfolds an infinite number of deep questions for us to take up and continue to ask.

I have a friend who once said to me that he writes his books to find out more about something that has captured his interest - this is a good description of writing: my books and other writings are also a way of exploration, of putting a lot of why questions, sometimes through telling stories, sometimes through discovering connections between phenomena and investigating the character of those phenomena themselves.

My most recent book looks at the soul - what people have imagined and defined when they inquired into the stuff that makes you you and me me - they came up with some weird suggestions, from fiery air, called ether, as well as ghost substances like ectoplasm. Now DNA gives the script for each individual self, but it doesn't quite communicate that person as someone you and I know ... that task is best left for literature and art to attempt.

Writing is done alone, but it is not made alone. Literature is an orchestra with a thousand - with 10,000 - players, some on strings, some on bells, some on nose flutes, some on tubas, drums, fifes, harps - some on the bones and the combs. These are other writers, and their works - and the process of writing - of putting those questions - involves engaging them in a continuous conversation.