Given the forecast by the futurist Ray Kurzweil that humans will reach the longevity escape velocity as early as 2029, I asked students in my class whether they would like to be immortal. After the longevity escape velocity is surpassed, our life expectancy will increase by more than a year for every passing year thanks to antiaging medicine.
To my surprise, one of the students said that he does not want to live forever because after a while he will get bored. I explained that boredom can happen out of inaction or lack of imagination even within our short lifespan today and that he can keep life exciting indefinitely by exploring the unknown. The student counter argued that eventually we will understand everything. This reminded me of the physicist Albert Michaelson who argued in 1896 that “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.” In subsequent decades after 1896, the special and general theories of relativity as well as quantum mechanics revolutionized our understanding of physical reality. I therefore reasoned to the student that figuring out the Universe is a never-ending quest because any knowledge that we gain will raise new questions. There is no way for our knowledge to saturate as long as we remain curious and hungry for new knowledge. People lose interest in life only when they lose the passion to learn more about the unknown.
I added that at an age of a billion years old, I would probably be much wiser than I am today. To those complaining about the weather at their residence on a habitable planet, I could explain how devastating it is to reside within tens of light years from a supernova, the nearest stellar explosion that one could witness within a billion years. I summarized my argument by telling the student: “When we both get to be a billion years old, let us have this conversation again and see if you still prefer not to be immortal.”
If antiaging medicine can deliver us immortality and quantum-gravity engineers will figure out a way to create a baby-universe in the laboratory, would there be anything else that God in religious belief systems can do and that science will not be able to do? If our science and technology acquired these capabilities, would it mean that humans reached the “religion escape velocity”? In other words, would there be benefits in subscribing to the traditional clubs of organized religions once science will offer us the same benefits right now for free?
Reaching the “religion escape velocity” would imply that our life will be guided by data science in the real physical reality that we all share, rather than by a belief system about a virtual reality that is contemplated beyond our four-dimensional experience. As much as I am confident that a billion-year version of myself will maintain agnostic curiosity, I am not convinced that other people can escape the mindset of believing in virtual realities. Let me explain.
It is evident from the polarized tribalism we witness on the right and the left of today’s political landscape that facts do not matter. This is even true for some science journalists, as became evident to me and my colleagues from The New York Times report last week. If people whose day job is to attend to facts, ignore facts in favor of a prescribed narrative, virtual realities will do better than facts in the minds of their readers. The benefit of virtual worlds is that they are under no obligation to satisfy the constraints of logic and empirical evidence, just like science fiction. As such, the virtual worlds offer a wider spectrum of options to their promoters. A large community of believers can march confidently to a cliff and jump into the abyss, even when science promises them immortality. They would do it just as suicide bombers do it, because of the promise of an imaginary benefit that the real world cannot offer because of logic or the laws of physics.
Even within theoretical physics, one could find a large contingency of believers in a new symmetry of nature, Supersymmetry, after the Large Hadron Collider at CERN ruled it out in its natural range of parameters. The argument raised by the believers is that Supersymmetry will show up once we increase the energies of the colliding particles to greater values. Clearly, this belief in Supersymmetry could be sustained indefinitely like any other belief in a virtual world.
Given the temptation to believe in virtual realities, it is difficult to imagine a future in which humans will reach the religion escape velocity. As I have no desire to change human nature, all I could say to my students is that I personally would love to continue this conversation a billion years from now. At that point, one of the students raised a practical question.
The question was what to do with newly born babies as the resources on Earth are limited and the population cannot grow indefinitely. The student asked: “Does this mean that once we saturate the use of our resources, we will need to kill an old person for every newborn?” This is what biology did for us naturally before 2029. If our limited resources will force us to limit human lifespan intentionally, the world will not be qualitatively different from the way it is today.
In reply, I proposed that humanity will venture into interstellar space. There is a huge reservoir of real estate and resources on exoplanets that humans can tap once they become immortal. Settling on these distant territories would ease the pressure of limited resources on Earth. Through its subtle generosity, the Universe offers us the prospects of immortality in interstellar space. When I am a billion years old, I hope to hold my class on an exoplanet, thousands of light years away.
Yesterday, Elon Musk announced that “A future Starship, much larger and more advanced, will travel to other star systems.” And so, I just started calculating with a brilliant Harvard College student in my class, Shokhruz Kakharov from Uzbekistan, the trajectory of a Starship in the Milky-Way galaxy, depending on its initial velocity. On this ship, I would love to have the company of immortal curious minds that maintain their childhood curiosity. With such an expedition team, we will definitely exceed the escape velocity from the virtual realities of those who stay on Earth.
ABOUT THE AUTHOR
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 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”, was published in August 2023.
