Just over a year ago, when my wife, Tule, died after a short, terrible battle with advanced breast cancer, everyone said it was a mercy, and probably for the best. Gently, with kindness and compassion, they assured me that this beautiful, talented, spirited woman would not have wanted to go on living that way, lying helpless in bed, the cancer that had so rapidly spread to her brain robbing her of the ability to speak or to move, her body wasting, the light in her lovely eyes fading, fading, fading away. And in my mind I knew that they probably...