Almost 30 years ago, Pico Iyer took a trip to Japan, fell in love with the country and moved there. A keen observer of the human spirit, Iyer professes that he now feels he knows far less about Japan — or, indeed, about anything — than he thought he knew three decades ago. In this lyrical meditation on wisdom, Iyer expands on this curious insight about knowledge gained with age: that the more we know,…