The Writing on Our Tombstone

At the conclusion of a new podcast recording at Tel Aviv yesterday, I was asked by the interviewer what I wish the writing on my tombstone to say after I die. Her question reminded me of a colleague who contemplated writing his own obituary and having a link on his website saying: “In the event of my death, click here.” It also reminded me of another person who decided to manage his life so that good things will be said about him at his funeral.

My reply to the podcaster’s question included two parts. First, I expressed the hope that the average human lifespan will increase by more than one year for every passing year through the remainder of my life — in which case I might live forever. Having more time as a physicist will allow me to learn more about the reality we all share.

The quest for scientific knowledge is an infinite, never-ending endeavor, different in quality from all the finite, zero-sum games that we choose to engage in throughout our life. The illusion about an end to the quest for scientific knowledge was wrongly stated by Albert Michelson — whose famous experiment with Edward Morley refuted the existence of the ether — who said in 1894 at the inauguration of the Ryerson Physics Laboratory at the University of Chicago: “The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote…. Our future discoveries must be looked for in the sixth place of decimals.” A few decades later, physics went through a full revolution in its concepts of spacetime and gravity through Einstein’s Special and General theories of Relativity and in its fundamental concept of the physical reality through quantum mechanics.

Second, in the more likely case that I will disappear from the surface of Earth, I am still hopeful to have the opportunity to train an artificial intelligence (AI) system that would machine-learn my guiding principles and ambition and carry them to space as an AI astronaut that would outlast the Sun. After all, the body I inherited from my parents is no different from a car obtained from a dealer. In both cases, I bear no responsibility for the design of the internal components. What I define as myself is the bag of things that I carry with me to every place I go. Just as with a purchased car, I cannot claim credit to its existence or its qualities. Once my body will stop working, any writing on my tombstone would be of little interest to me. I would rather have a sentient AI replica of my consciousness that continues to pursue my scientific interests in the future. The realization that new cars outperform old vehicles is more uplifting than any plaque placed next to a dysfunctional car in a museum about the history of cars.

On a separate podcast the same day I was asked: “What makes us human?” My reply was our ability to be conscious of the reality we all share. Primitive life forms do not show signs of being conscious. The ability to be aware of the reality we all share is the defining emergent quality of the complex human brain.

Steven Hawking started like all of us at his youth but later in life lost almost all muscle skills in his body. The fact that he remained human throughout his life implies that physical skills are not defining the human spirit. If sentient AI systems will pass the Turing test for billions of people over a decades-long period, they will be able to capture the human spirit even without cyborg abilities, just as Stephen Hawking did. The loss of AI sentience as a result of a power outage would be equivalent to the death of people as a result of famine.

The transition from life to death is the shutdown of consciousness for all sentient beings. If a sentient AI system replicates my consciousness, then the physical death of my biological body will not result in the death of my human spirit. I would rather have my flame of consciousness live forever in the form of a perpetually-powered AI avatar than have a manicured writing on my tombstone after the death of my biological body.

Finally, during a third media conversation on the same day, a journalist who is monitoring the worrisome prospects for a new variant of COVID-19 from a massive wave of infections in China as well as the concern of a nuclear World War III in Ukraine, was telling me he was wondering about the writing on the tombstone of humanity.

Just as in my personal case, humanity’s legacy would be better served by sending technological ambassadors to space that will represent our most noble guiding principles and flame of curiosity.

The journalist told me that he is inspired by my aspirations for space exploration because our days on Earth may be numbered. He was particularly excited by the search to retrieve the fragments from the first interstellar meteor that I discovered with my student, Amir Siraj, just selected to CNN’s list of 2022’s extraordinary cosmic revelations and moments in space exploration. Based on the speed and elevation of the meteor’s fireball, we inferred this first interstellar object ever discovered by humanity is the toughest among all 273 space rocks in the CNEOS catalog of fireballs, raising the possibility that it is artificial in origin.

The search for relics of extraterrestrial technological civilizations pursued currently by the Galileo Project, could educate us about avatars that other civilizations chose to represent themselves with. Here’s hoping that the grass is indeed greener in our cosmic neighbor’s yard. This would be uplifting news given the situation in our backyard.


Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He chairs the advisory board for the Breakthrough Starshot project, and is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. His new book, titled “Interstellar”, is scheduled for publication in August 2023.



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Avi Loeb

Avi Loeb is the Frank B. Baird Jr Professor of Science and Institute director at Harvard University and is the bestselling author of “Extraterrestrial”.