When we lived in a society where we had large families that lived together, especially in agricultural societies like my grandfather and father grew up in, the result is you always had family around to take care of you.

No travel ban or quarantine will seal a country completely. Even if travel could be reduced by eighty per cent-itself a feat-models predict that new transmissions would be delayed only a few weeks. Worse, it would only drive an increase in the number of cases at the source. Health-care workers who have fallen ill would not be able to get out for treatment, and the international health personnel needed to quell the outbreak would no longer be able to go in.

What is the alternative to understanding the complexity of the world?

You want to ensure people can do it right 99 percent of time. When we have to fire one of our surgical trainees, it is never because they dont have the physical skills but because they dont have the moral skills - to practise and admit failure.

Sometimes we can offer a cure, sometimes only a salve, sometimes not even that. But whatever we can offer, our interventions, and the risks and sacrifices they entail, are justified only if they serve the larger aims of a person's life. When we forget that, the suffering we inflict can be barbaric. When we remember it the good we do can be breathtaking.

Practice is funny that way. For days and days, you make out only the fragments of what to do. And then one day you've got the thing whole. Conscious learning becomes unconscious knowledge, and you cannot say precisely how.

In the end, people don't view their life as merely the average of all its moments-which, after all, is mostly nothing much plus some sleep. For human beings, life is meaningful because it is a story. A story has a sense of a whole, and its arc is determined by the significant moments, the ones where something happens. Measurements of people's minute-by-minute levels of pleasure and pain miss this fundamental aspect of human existence. A seemingly happy life maybe empty. A seemingly difficult life may be devoted to a great cause. We have purposes larger than ourselves.