I had dinner with people who had studied meditation deeply. It was a gathering with a renowned meditation teacher, a senior monk, a psychiatrist from a university hospital, the chairman of a large company, and many others. As various topics came and went, the subject of Daniel Kahneman came up.
Daniel Kahneman was born in Tel Aviv in 1934. He spent his childhood in France under Nazi occupation. He was Jewish, and he survived. He once said that experience of survival made him a psychologist. Why do human beings behave so irrationally? That question shaped his entire life. Together with Amos Tversky, his lifelong intellectual partner, he studied cognitive biases and heuristics and received the Nobel Prize in Economics in 2002. It was unprecedented for a psychologist, rather than an economist, to receive the economics prize. Thinking, Fast and Slow sold more than four million copies, and his name spread beyond academia into business, policy, and everyday language. Fast thinking and slow thinking, System 1 and System 2. These were the languages he created.
He suffered loss for a long time. Tversky, his lifelong intellectual partner, died of cancer in 1996. Kahneman was 62 then. Afterward, he grew close to Tversky’s wife, Barbara, and the two were together. His wife, Anne Treisman, died of vascular dementia in 2018. He watched one of the great minds of cognitive science lose her cognitive abilities. In a letter that came to light later, he wrote that the experience had left a deep mark on him.
In March 2024, Kahneman turned 90. He flew to Paris with his partner, Barbara. His daughter and her family were waiting there. They walked around Paris for several days. They visited museums, watched ballet, and ate soufflé and chocolate mousse. Around March 22, he began sending emails to dozens of close acquaintances. They were not short letters. On March 26, he left his family and boarded a plane alone for Zurich. The next day, March 27, he ended his life through assisted death in Switzerland.
The contents of the emails were made public through the Wall Street Journal a year later. He wrote that he did not want to endure the pain and humiliation of aging unnecessarily. He had watched his mother, his wife Anne, and other people close to him go through that process. He did not have dementia and did not need dialysis, but he could feel his mind making frequent mistakes and his kidney function declining. He added that he knew many people would consider it too early, but that was precisely his intention. If he waited until life was clearly no longer worth living, he would already have lost the ability to make that judgment. True to his mastery of decision theory, he designed his final decision with the greatest precision.
The monks who were there spoke quietly. About the deaths they had witnessed. One said that someone had seemed to wait for a moment when there was no one else in the room, just before taking their last breath. Another said that someone had lingered for a long time but found peace at the very end. They said every death was different, with no discernible pattern. But if there was one thing they had in common, it was this: facing death, people die in the way they lived.
With those words still on my mind, I offered an unlikely thought. What if a future comes when, if we live just a little longer, we no longer have to die?
It began like a joke, but I was serious. I believe rejuvenation technology will be developed and become widely available in the not-too-distant future. Bryan Johnson is using his own body as a laboratory and collecting data every day, while Altos Labs is spending billions of dollars researching cellular reprogramming. Unless they suffer an exceptional accident, human beings may become beings that do not die. Our generation may even witness that possibility becoming reality.
When that happens, what will Kahneman’s choice mean? He chose to die at 90. Before he could no longer think sharply, before he gave up being himself. But in a world where rejuvenation has been conquered, that reason disappears. If both the body and the mind can be rewound. Then when, and for what reason, will people choose death in that world?
There is a saying that once you have lived long enough, you can die without regrets. Right now, this is a feeling that comes naturally with age. As the body slows down, memory grows hazy, and the people around you leave first. But after rejuvenation, that preparation will not come. The body will continue to function as it did in your thirties. Even if someone has lived for a thousand years, if there is still something they want to do, they will not die. Conversely, what if someone has lived for a thousand years and already done everything there is to do?
That was the question that kept branching through the night. When you have done everything a human being can do, what comes next? Food is finite. Language is finite. Places you can visit, relationships you can have, and professions you can try will all eventually be exhausted. If humanity is still creating new art, technology, and philosophy 1,000 years from now, perhaps boredom will not come to a curious person.
But the problem is the threshold. The wonder you feel when you see the ocean for the first time is not the same as the wonder you feel when you see it for the thousandth time. The feeling of falling in love with someone for the first time is not the same as falling in love for the twelfth time. Even if rejuvenation can rewind cells, it cannot rewind memory. You are still someone who has seen the ocean a thousand times. As the weight of those memories accumulates, the size of the wonder brought by something new grows smaller and smaller. The first thing an immortal human being may lose is the ability to be amazed.
And then there is love. While you live for 1,000 years, someone will leave this world. Someone you spent 100 years with disappears one day in a car accident. Someone you spent 200 years with leaves the future as well, taken by some unexplained illness. An immortal person will repeat partings endlessly. If someone who has lived for 1,000 years chooses death, perhaps it will not be because they are bored, but because they can no longer bear having anything left to lose.
I think again of what the monks said. That facing death, people die in the way they lived. That still seems true after rejuvenation. A curious person will keep looking for something new until one day they quietly stop. Someone who found meaning in relationships will leave when no one is left. Someone who valued autonomy above all else, like Kahneman, will choose at the final moment when they are still able to choose.
Even in a future where death has disappeared, people will die. Only the reasons will be different. Now death comes to us, but then we will go looking for death. The meaning of having lived long enough will simply expand from 30 years to 300, and from 300 years to 3,000. We may feel what Kahneman felt at 90 when we are 900. The form will change, but the questions will be the same. Am I enough of myself right now? Is it okay to go now?
The day we can answer those questions will be the most important day of our lives. Now, and 1,000 years from now.
