I've had the good luck to have an intense sense of spirituality. One of the early books I read, which was called the Wisdom of the Body, in hardcover, and then the publisher decided to call it How We Live in paperback.

It's a book introducing the biology of the human body… to a general reader, and when I had written all of the chapters about the cardiac system and the nervous system and the gastrointestinal system, I wrote a section about what I called the human spirit, which I really felt was a genetic response… to 200,000 years of human evolution. You know, Homo sapiens appeared on Earth about 200,000 years ago, and my sense was that… spirituality was of benefit… to a biological creature, and as time went on, as in all evolutionary processes, those genetically favoured with a sense of spirituality survived, and this is why the human being has it. And I had what I thought of as evidence for it… primarily from the world of art, from the aesthetic sense. From music, particularly. Music seems to me to bring out my sense of spirituality more than anything else does. Sometimes reading some very wise moral philosopher will do the same thing for me. Sometimes, discussing issues, that old, old issue of why we are the way we are, which has intrigued me forever. Sometimes discussing that gives me a tremendous spiritual sense.