Of course, she could not stop my intense reading. Poring over studies, I kept trying to find the one that would tell me when my number would be up. The large general studies said that between 70 and 80 percent of lung cancer patients would die within two years. They did not allow for much hope. But then again, most of those patients were older and heavy smokers. Where was the study of nonsmoking 36-year-old neurosurgeons? Maybe my youth and health mattered? Or maybe my disease was found so late, had spread so far, and I was already so far gone that I was worse off than those 65-year-old smokers.

Many friends and family members provided anecdotes along the lines of my-friend’s-friend’s-mom’s-friend or my-uncle’s-barber’s-son’s-tennis-partner has this same kind of lung cancer and has been living for 10 years. Initially I wondered if all the stories referred to the same person, connected through the proverbial six degrees. I disregarded them as wishful thinking, baseless delusion. Eventually, though, enough of those stories seeped in through the cracks of my studied realism.

And then my health began to improve, thanks to a pill that targets a specific genetic mutation tied to my cancer. I began to walk without a cane and to say things like, “Well, it’s pretty unlikely that I’ll be lucky enough to live for a decade, but it’s possible.” A tiny drop of hope.

In a way, though, the certainty of death was easier than this uncertain life. Didn’t those in purgatory prefer to go to hell, and just be done with it? Was I supposed to be making funeral arrangements? Devoting myself to my wife, my parents, my brothers, my friends, my adorable niece? Writing the book I had always wanted to write? Or was I supposed to go back to negotiating my multiyear job offers?

The path forward would seem obvious, if only I knew how many months or years I had left. Tell me three months, I’d just spend time with family. Tell me one year, I’d have a plan (write that book). Give me 10 years, I’d get back to treating diseases. The pedestrian truth that you live one day at a time didn’t help: What was I supposed to do with that day? My oncologist would say only: “I can’t tell you a time. You’ve got to find what matters most to you.”

I began to realize that coming face to face with my own mortality, in a sense, had changed both nothing and everything. Before my cancer was diagnosed, I knew that someday I would die, but I didn’t know when. After the diagnosis, I knew that someday I would die, but I didn’t know when. But now I knew it acutely. The problem wasn’t really a scientific one. The fact of death is unsettling. Yet there is no other way to live.