along the way. Whenever serious sickness or injury strikes and your body or mind breaks down, the vital questions are the same: What is your understanding of the situation and its potential outcomes? What are your fears and what are your hopes? What are the trade-offs you are willing to make and not willing to make? And what is the course of action that best serves this understanding? The field of palliative

No, the more familiar and widely dangerous issue is a kind of silent disengagement, the consequence of specialized technicians sticking narrowly to their domains. “That’s not my problem” is possibly the worst thing people can think, whether they are starting an operation, taxiing an airplane full of passengers down a runway, or building a thousand-foot-tall skyscraper.

You do not imagine that a mere matter of etiquette could foil you. But the social dimension turns out to be as essential as the scientific — matters of how casual you should be, how formal, how reticent, how forthright. Also: how apologetic, how self-confident, how money-minded.

It turns out that inheritance has surprisingly little influence on longevity. James Vaupel, of the Max Planck Institute for Demographic Research, in Rostock, Germany, notes that only 3 percent of how long you’ll live, compared with the average, is explained by your parents’ longevity; by contrast, up to 90 percent of how tall you are is explained by your parents’ height. Even genetically identical twins vary widely in life span: the typical gap is more than fifteen years. If our genes explain less than we imagined, the classical wear-and-tear model may explain more than we knew.

Arriving at meaningful solutions is an inevitably slow and difficult process. Nonetheless, what I saw was: better is possible. It does not take genius. It takes diligence. It takes moral clarity. It takes ingenuity. And above all, it takes willingness to try.

The investigators at Johns Hopkins and elsewhere had also observed that when nurses were given a chance to say their names and mention concerns at the beginning of a case, they were more likely to note problems and offer solutions. The researchers called it an “activation phenomenon.” Giving people a chance to say something at the start seemed to activate their sense of participation and responsibility and their willingness to speak up.

Studies find that as people grow older they interact with fewer people and concentrate more on spending time with family and established friends. They focus on being rather than doing and on the present more than the future.