Separating Science from Fiction

Avi Loeb
5 min readMar 5, 2023


Credit: Britannica

Magical thinking posits that everything imaginable is possible. It is an addictive recreational drug consumed not only by non-professionals but also by some mainstream scientists who believe in the multiverse and argue that “anything that can happen will happen an infinite number of times.

In a recent interview with Stephen Colbert, Steven Spielberg suggested that Unidentified Aerial Phenomena (UAP) may be extraterrestrial in origin. His threshold for suggesting that is acceptable for science-fiction scripts in Hollywood, but not for science.

What makes science different from fiction? In one word: evidence.

People may say whatever they want. Some, like Bob Lazar, say the same thing about UAP persistently for decades. But persistence does not make what he says true without direct evidence to substantiate his claims. A person insisting for decades that he is Napoleon Bonaparte without showing evidence to support it, will not be featured on the political arena in France but rather be placed in a mental hospital. What separates these outcomes? Evidence and common sense. Napoleon would have been 254 years old to be alive today.

The need to rely on evidence irrespective of human testimonies is obvious from conflicting reports by eyewitnesses of car accidents or by fans at sport events. They all witness the same reality but come up with different and sometimes conflicting reports. High-resolution videos could resolve controversies, as recently demonstrated by FIFA in the 2022 Soccer World Cup.

Similarly to the service provided by video cameras for soccer referees, well-calibrated scientific instruments could guide us towards a sober view of reality without wishful thinking about what we want it to be. When military personnel report about UAP, as discussed in the 2022 report from the Director of National Intelligence to the US Congress, we should be intrigued. There is no doubt that the reports indicate something unusual but the public evidence we have at hand is not sufficient to support Spielberg’s assertion. To substantiate any interpretation by facts, we must follow the scientific method and collect new data. This underlines the scientific agenda of the Galileo Project, which constitutes the first systematic research program aimed at collecting extensive UAP data over a long time in many locations with well-calibrated instruments and using artificial intelligence classification to determine whether all objects are familiar as either natural (like bugs, birds or rocky meteors) or human-made (like balloons, drones, airplanes, satellites or rockets).

Today’s measurement instruments are far better than those available decades ago. Moreover, the sky is not classified. Therefore, we should not obsess with incomplete data in old reports but rather collect new high-quality data and figure out whether there are extraterrestrial objects in our sky.

As much as this theme follows common sense, I witness pushback against it from both skeptics and believers in the extraterrestrial origin of some UAP. Apparently, common sense is not common. Both sides of the argument would prefer to avoid the scientific method in order to preserve their traditional way of thinking.

This realization may not be surprising based on human history. Paradigm shifts require individuals who are willing to examine possibilities that are ridiculed by mainstream scientists. But the uphill battle is even more catastrophic for propositions which are not aligned with societal norms, like the suggestion made by Giordano Bruno that exoplanets may exist around other stars.

The lesson learned is that the validity of ideas should not be judged by popularity contests as measured by the number of “likes” they get on Twitter, but rather by the scientific evidence that supports them. Assembling this evidence is hard work. It requires funding, design and assembly of state-of-the-art instrumentation, testing and calibration, careful collection of data, and quantitative analysis of this data. For example, knowing the distance to UAPs is crucial in inferring their speed and acceleration. A reliable distance measurement requires triangulation from multiple sites or an active radar pulse.

When Ukrainian astronomers reported distance measurements to dark objects from only one site, I pointed out in a paper that their inferred speeds are likely incorrect because at these distances the objects would have resulted in bright fireballs and would have not appeared dark. My assessment was immediately rejected by believers in the extraterrestrial UAP hypothesis, who suggested new physics to explain the discrepancy. What they are missing is that the bar for new physics is far higher than incomplete data. In order to argue for new physics, or even non-human technologies based on known physics, one must have high-quality data that rule out any other interpretation, like incorrect distance measurements, beyond a reasonable doubt. The burden of proof is on those who claim new physics. Progress in our scientific knowledge is not advanced by our imagination but by indisputable supporting evidence. Without accurate distance measurements, UAP observations cannot be used to suggest new physics.

As reasonable as it sounds, the principle of being guided by evidence is not popular. Human nature favors a virtual reality that is more exciting or flattering than the actual reality is. If we do not like the way we look in the mirror or in photographs, we put on make-up, we photoshop our pictures, or we subscribe to a dating app that improves our look in the virtual world. This tendency explains the popularity of the multiverse in science and the metaverse in Silicon Valley.

But there is hope. While the above tendency characterizes adults, it is less prevalent among kids who humbly and sincerely wish to learn about the world from evidence without prejudice or wishful thinking. Here’s hoping that all of us will keep our childhood curiosity well into adulthood and maintain the beginner’s mind (Shoshin) advocated by Zen Buddhism.

The motivation for attending to the reality we all share is simple: it allows us to adapt to its true nature and propels our future technological advances. Physicists of the early Twentieth Century never imagined Quantum Mechanics which established the foundation for modern computers, lasers, cell phones and the internet. But there is also a secondary benefit. Seeking evidence instead of magical thinking to guide us will raise our status in the class of intelligent civilizations within the Milky-Way galaxy.


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.



Avi Loeb

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