A Word of Torah About Extraterrestrials

Spirituality and the frontiers of science have something in common: they both explore the unknown. This is not an easy task. It is far more comforting to explore what is known. We know all about the ordinary matter that makes luminous stars, but some scientists search for dark matter without knowing its nature. We do not know whether there are sentient extraterrestrials, but some scientists search for them.

The unknown brings existential risks. But given that we live for such a short time, less than a part in a hundred million of cosmic history, the fundamental choice is between living a comfortable and predictable life or charting a road not taken with the glimmer of hope that it will offer new revelations. Anything discovered along the unbeaten path will be our own. As Frank Sinatra sang: “And now the end is here/And so I face that final curtain/My friend I’ll make it clear/I’ll state my case, of which I’m certain/I’ve lived a life that’s full/I traveled each and every highway/And more, much more/I did it, I did it my way.”

There are two fundamental differences between spirituality and science. Whereas spirituality is guided by a personal experience, science is guided by a universal experience. In the former, the unique interaction between the individual and the world dictates the outcome whereas in the latter it is a realization that can be shared equally by all scientists. Whereas the spiritual experience is fresh and unique to an individual, the scientific experience is universally shared by all scientists once discovered. The dialogue with God is an “I and Thou” experience, unique to the individual, in Martin Buber’s existential philosophy. The bending of light by clusters of galaxies implies the presence of dark matter to all scientists who adopt Albert Einstein’s theory of gravity.

Another difference involves the nature of evidence. In science, reliable evidence must be quantitative, reproducible and collected by instruments which are fully calibrated and under control. However, spirituality revolves around the human experience and does not rely on instrumentation as the mediator of revelations.

For these reasons, I was surprised to receive an email two days ago from Rabbi Elyssa Joy Austerklein, starting with the sentence: “With admiration and respect, I want to share with you my Dvar Torah from Yom Kippur, which highlights your book Extraterrestrial.” Dvar Torah (meaning `A Word of Torah’ in Hebrew) is an essay based on the weekly portion of the Hebrew Bible. The Mishnah (Avot 3:3) states that a table over which no Dvar Torah is shared is compared to an altar upon which offerings are brought to idols; conversely, a table where D’var Torah is spoken is akin to God’s table. In today’s terminology, “no Dvar Torah” would be equivalent to the common threads regarding idols on social media.

Elyssa’s inspiring essay pays special attention to the statement from my book: “If you don’t expect the unexpected, you’ll never see it.” She gives it the proper interpretation: “We need to be constantly aware of our limits and be seeking to expand them. If we are sure that what we experience or know is as we predicted, then we don’t leave room for growth […] Sometimes we think that we are open to what we don’t know or haven’t experienced before, but really we are just trying to prove what we already believe or know. We haven’t made the space for the unknown. We haven’t expected the unexpected […] How does our desire to predict and control actually affect the outcome? How do our calculations, at times, actually determine the course of events?” She adds: “Astrophysicist Dr. Loeb also said: “Truth and consensus may never be conflated.” As a society, we are dangerously falling prey to this conflation.” And she concludes by stating: “We must venture into the unknown […] On this Yom Kippur day, as we empty our bodies of physical sustenance, may we empty ourselves of preconceptions and begin a new journey towards expecting the unexpected -Gmar Chatimah Tovah — May you be sealed in the Book of Life.”

What unifies spirituality and our scientific study of the Universe is a sense of awe and humility. No, we are not at the center of the stage and we arrived to the cosmic play after 13.8 billion years, so how can we imagine that the play is about us? Indeed, the Earth-Sun system is not unique or privileged. But many of us still insist on owning the last territory on which our ownership was not disputed as of yet: “Yes, we are the only sentient beings in the Universe.”

Well, let me offer some breaking news on this last item. Within this century, Artificial Intelligence (AI) systems will likely appear sentient in the most elaborate Turing Tests that the human mind can imagine. Within this century, astronomers are likely to discover evidence for a smarter kid on our cosmic block, not in the form of radio signals but in the form of weird interstellar objects — identified by the advanced AI algorithms of the Galileo Project. And finally, within this century we might realize that other sentient beings already exist on Earth. Check out the following article and video on bonobos. So far, bonobos were educated to communicate with us in our language, but AI systems can be used to educate us about their language. All in all, AI systems will serve as our tutor, bringing the next Copernican revolution in which we would realize that consciousness and sentience are emergent phenomena shared by non-humans.

Given our status as inconsequential spectators of the cosmic scene, what should we do? We could celebrate the metaphorical routine of “eating leaves in our jungle”, as bonobos did for nearly a million years. Or we can explore the unknown, expecting the unexpected. The choice is ours.


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.



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Avi Loeb

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”.