Author Paul Ham on how the soul has driven our history

It's a book that could well change your life. That's the claim from author Paul Ham, who says his life changed for the better as he wrote his latest book "The Soul: A History of the Human Mind" and in the process became more optimistic about humanity. The book aims to show how belief in the soul, and beliefs arising from the soul or mind, have animated and driven our history. He spoke to us in Perspective.