I would take away fear.

Doc Brown proved that editing the past is disastrous.

I would be less naive.

There was a very large part of my 20s where I was an alcoholic, and an addict. When I lost my dad to cirrhosis, I knew that the only difference between us was that, tragically, he couldn’t stop whereas I could.

I’ve had this concern all the time, but I can only hope that if one writes with appreciation and delicacy and respect, then it’s okay. I have to say that I’ve written a hundred times as much as I’ve published, because if there’s any thought of offense or embarrassment, then I will put the thing quietly away.

It was this celestial splendor that suddenly made me realize how little time, how little life, I had left. My sense of the heavens’ beauty, of eternity, was inseparably mixed for me with a sense of transience — and death. ... I told my friends Kate and Allen, “I would like to see such a sky again when I am dying.” “We’ll wheel you outside,” they said.

I cannot pretend I am without fear. But my predominant feeling is one of gratitude. I have loved and been loved; I have been given much and I have given something in return; I have read and traveled and thought and written. I have had an intercourse with the world, the special intercourse of writers and readers. Above all, I have been a sentient being, a thinking animal, on this beautiful planet, and that in itself has been an enormous privilege and adventure.

My generation is on the way out, and each death I have felt as an abruption, a tearing away of part of myself. There will be no one like us when we are gone, but then there is no one like anyone else, ever. When people die, they cannot be replaced. They leave holes that cannot be filled, for it is the fate — the genetic and neural fate — of every human being to be a unique individual, to find his own path, to live his own life, to die his own death.

And I spent four years at a boarding school in the country, probably a rather abusive boarding school, and seeing very little of my parents, and that was a very bad time for me. A bad and almost a mad time. ... I think that some sort of trust, and ability for closeness, may have been compromised. And I think I’ve perhaps, to some extent, sort of kept a distance since that time, although this is not a distance I feel with my patients or my students.

I feel a sudden clear focus and perspective. There is no time for anything inessential. I must focus on myself, my work and my friends. I shall no longer look at “NewsHour” every night. I shall no longer pay any attention to politics or arguments about global warming. This is not indifference but detachment — I still care deeply about the Middle East, about global warming, about growing inequality, but these are no longer my business; they belong to the future. I rejoice when I meet gifted young people — even the one who biopsied and diagnosed my metastases. I feel the future is in good hands.