In psychology, there's something called the broken-leg problem. A statistical formula may be highly successful in predicting whether or not a person will go to a movie in the next week. But someone who knows that this person is laid up with a broken leg will beat the formula. No formula can take into account the infinite range of such exceptional events.

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.

The definition of what it means to be dying has changed radically. We are able to extend people's lives considerably, including sometimes, good days.

The possibilities and probabilities are all we have to work with in medicine, though. What we are drawn to in this imperfect science, what we in fact covet in our way, is the alterable moment-the fragile but crystalline opportunity for one's know-how, ability, or just gut instinct to change the course of another's life for the better.

The big thing that's happened is, in the time since the Affordable Care Act has been going on, our medical science has been advancing. We have now genomic data. We have the power of big data about what your living patterns are, what's happening in your body. Even your smartphone can collect data about your walking or your pulse or other things that could be incredibly meaningful in being able to predict whether you have disease coming in the future and help avert those problems.

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

The evidence is that people who enter hospice don't have shorter lives. In many cases they are longer.