The three primary risk factors for falling are poor balance, taking more than four prescription medications, and muscle weakness. Elderly people without these risk factors have a 12 percent chance of falling in a year. Those with all three risk factors have almost a 100 percent chance.

Leonid Gavrilov, a researcher at the University of Chicago, argues that human beings fail the way all complex systems fail: randomly and gradually.

In all such cases, death is certain, but the timing isn’t. So everyone struggles with this uncertainty—with how, and when, to accept that the battle is lost.

THERE REMAINS ONE problem with this way of living. Our reverence for independence takes no account of the reality of what happens in life: sooner or later, independence will become impossible.

This is what it means to have autonomy—you may not control life’s circumstances, but getting to be the author of your life means getting to control what you do with them.

We end up with institutions that address any number of societal goals—from freeing up hospital beds to taking burdens off families’ hands to coping with poverty among the elderly—but never the goal that matters to the people who reside in them: how to make life worth living when we’re weak and frail and can’t fend for ourselves anymore.

As people become aware of the finitude of their life, they do not ask for much. They do not seek more riches. They do not seek more power. They ask only to be permitted, insofar as possible, to keep shaping the story of their life in the world—to make choices and sustain connections to others according to their own priorities.

A seemingly happy life may be empty. A seemingly difficult life may be devoted to a great cause. We have purposes larger than ourselves.

There are no more backups. We wear down until we can’t wear down anymore.