“If there is a lesson here it has to do with humility. For all our vaunted intelligence and complexity, we are not the sole authors of our destinies or of anything else. You may exercise diligently, eat a medically fashionable diet, and still die of a sting from an irritated bee. You may be a slim, toned paragon of wellness, and still a macrophage within your body may decide to throw in its lot with an incipient tumor.”