Whenever I am unable to walk, climb or sail away from the world, I have learned to shut it out.
 
Learning this took time. Only when I understood that I had a primal need for silence was I able to begin my search for it—and there, deep beneath a cacophony of traffic noise and thoughts, music and machinery, iPhones and snow ploughs, it lay in wait for me. Silence.
 
Not long ago, I tried convincing my three daughters that the world’s secrets are hidden inside silence. We were sitting around the kitchen table eating Sunday dinner. Nowadays it is a rare occurrence for us to eat a meal together; so much is going on all the other days of the week. Sunday dinners have become the one time when we all remain seated and talk, face-to-face.
 
The girls looked at me sceptically. Surely silence is . . . nothing? Even before I was able to explain the way in which silence can be a friend, and a luxury more valuable than any of the Louis Vuitton bags they so covet, their minds had been made up: silence is fine to have on hand when you’re feeling sad. Beyond that, it’s useless.
 
Sitting there at the dinner table, I suddenly remembered their curiosity as children. How they would wonder about what might be hiding behind a door. Their amazement as they stared at a light switch and asked me to “open the light.”
 
Questions and answers, questions and answers. Wonder is the very engine of life. But my children are thirteen, sixteen and nineteen years old and wonder less and less; if they still wonder at anything, they quickly pull out their smartphones to find the answer. They are still curious, but their faces are not as childish, more adult, and their heads are now filled with more ambitions than questions. None of them had any interest in discussing the subject of silence, so, in order to invoke it, I told them about two friends of mine who had decided to climb Mount Everest.
 
Early one morning they left base camp to climb the southwest wall of the mountain. It was going well. Both reached the summit, but then came the storm. They soon realized they would not make it down alive. The first got hold of his pregnant wife via satellite phone. Together they decided on the name of the child that she was carrying. Then he quietly passed away just below the summit. My other friend was not able to contact anyone before he died. No one knows exactly what happened on the mountain in those hours. Thanks to the dry, cool climate 8,000 metres above sea level, they have both been freeze-dried. They lie there in silence, looking no different, more or less, from the way they were last time I saw them, twenty-two years ago.
 
For once there was silence around the table. One of our mobile phones pinged with an incoming message, but none of us thought to check our phones just then. Instead, we filled the silence with ourselves.
 
Not long afterwards, I was invited to give a lecture at St. Andrew’s University in Scotland. I was to choose the subject myself. I tended to talk about extreme journeys to the ends of the earth, but this time my thoughts turned homewards, to that Sunday supper with my family. So I settled on the topic of silence. I prepared myself well but was, as I often am, nervous beforehand. What if scattered thoughts about silence belonged only in the realm of Sunday dinners, and not in student forums? It was not that I expected to be booed for the eighteen minutes of my lecture, but I wanted the students to be interested in the subject I held so close to my heart.
 
I began the lecture with a minute of silence. You could have heard a pin drop. It was stock-still. For the next seventeen minutes I spoke about the silence around us, but I also talked about something that is even more important to me, the silence within us. The students remained quiet. Listening. It seemed as though they had been missing silence.
 
That same evening, I went out to a pub with a few of them. Inside the draughty entrance, each of us with a pint of beer, it was all more or less exactly the same as my student days at Cambridge. Kind, curious people, a humming atmosphere, interesting conversations. What is silence? Where is it? Why is it more important now than ever? were three questions they wanted answered.
 
That evening meant a lot to me, and not only for the good company. Thanks to the students I realized how little I understood. Back home I couldn’t stop thinking about those three questions. They became an obsession.
 
What is silence? Where is it? Why is it more important now than ever?
 
Every evening I’d sit, puzzling over them. I began writing, thinking and reading, more for myself than anyone else. By the end of my search I’d come up with thirty-three attempts at answering them.