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.

I chose surgery because I thought that perhaps this would make me more like the kind of person I wanted to be.

No matter what measures are taken, doctors will sometimes falter, and it isn't reasonable to ask that we achieve perfection. What is reasonable is to ask that we never cease to aim for it.

Making systems work is the great task of my generation of physicians and scientists. But I would go further and say that making systems work - whether in healthcare, education, climate change, making a pathway out of poverty - is the great task of our generation as a whole.

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.

Expertise is the mantra of modern medicine.

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.