The Simplicity of Telling the Truth

Avi Loeb
5 min readMar 25, 2023
Galileo before the Holy Office, a 19th-century painting by Joseph-Nicolas Robert-Fleury.

It is a great privilege to be a physicist because all you need to remember are the fundamental laws of nature and everything else is derived from them. There is no need to memorize individual phenomena because they represent manifestations of these laws. Knowing the laws that govern nature brings efficiency to the way you figure things out. All atoms in the Universe obey the same law of energy conservation with no exception.

The universality of physical laws is remarkable given the backdrop of human interactions. There are no universal laws that govern people, as evident from the busy schedule of the legal court system. In difference from atoms, there is always an abundance of people who break societal laws. Psychologists are well aware of the risk of forecasting human actions; if the individuals are aware of your forecast, some will violate it just for fun.

But even in human relationships, there is a path to better efficiency. It is followed by being truthful. If you speak the truth, you do not need to remember what you already said a while ago, because the truth is backed by reality and reality is always consistent with its past. Deviations from the truth require us to carefully craft subsequent deliberations so that they will be consistent. This in turn requires us to remember what was already said in order not to break apparent consistency and reveal the lie. After getting married, I told my wife that she can count on me being truthful in our relationship, because having an affair and remembering a false narrative is too much work. She noted: “This is not romantic.” But she quickly realized that she can count on it, just the way a physicist counts on the laws of physics. Both are efficient ways to maintain simplicity, honesty and trust.

Of course, the derivation of scientific truth is challenged by wishful thinking. Very often the desired conclusion is defined ahead of time before there is evidence to support it. In a PhD thesis defense that I once attended, a student developed the tools for testing the prevailing cosmological paradigm of Cold Dark Matter through a sophisticated model of galaxy clustering. When I asked the student: “What will happen if future data disagrees with the generic predictions of the Cold Dark Matter model?”, the reply was: “Then I will know that my model for galaxy clustering is oversimplified and I will revise it so that the data will fit the Cold Dark Matter paradigm.” Similarly, when I asked a colloquium speaker about the “swampland landscape” of string theory: “Suppose we collect future data on the cosmic microwave background that violates your predictions, would that rule out string theory?”, the reply was: “No, that would prove that my simplified conjecture about the phenomenology of string theory is wrong. String theory must be right.”

Similarly, in a recent podcast interview of “UnHerd Ideas,” the host Flo Read quoted some of my colleagues as saying, “We are 100% confident that the first reported interstellar object, `Oumuamua, was not manufactured by a technological civilization.” In reply, I noted: “This statement reflects more on those who said it than it does about `Oumuamua.” Those who are 100% sure of anything based on partial evidence are believers, not scientists.

On the same day, I received a gift in the mail from Italy, containing an old copy of the Inquisition trial documents in the prosecution of Galileo Galilei, concerning his “heretical view” regarding the popular assertion that the Sun moves around the Earth. It is evident from the deliberations that the prosecution was 100% convinced in the validity of this popular assertion. Four centuries later, should we adhere to the same standards of deliberations and evidence by planetary scientists or string theorists?

The present-day circumstances became apparent in the way that science reporters responded to a theoretical model for the interstellar object `Oumuamua proposed by Jennifer Bergner and Darryl Seligman in a Nature paper last week. The model argued that `Oumuamua was a generic water iceberg, processed by cosmic-rays along its interstellar journey. This view of a generic iceberg was instantly embraced by mainstream advocates of nothing new under the Sun.

It is wonderful to witness creative ideas at the frontiers of science being publicly celebrated, as long as the associated model satisfies energy conservation. A day after the widespread press release, Thiem Hoang and I showed in a new paper that the energy budget in the Nature paper neglected the cooling effect associated with the evaporation of molecular hydrogen near the Sun. Proper account of the evaporative energy loss lowers the surface temperature by a factor of 9 and weakens the rocket effect by more than a factor of 3, making the proposed model untenable as an explanation for the non-gravitational acceleration of `Oumuamua. When science reporters learned about the follow-up paper, many of them chose not to report about the energy conservation issue in order “not to confuse the readers.”

Galileo’s trial implies that in science it is better to debate a possible mistake about the interpretation of reality than to hide it from view, because eventually it will be revealed. How can we complain about misinformation by politicians if science journalists choose not to report the full truth in order to “protect” their audience from it? A brief correction to their readership could have included the footnote: “Hoang and Loeb wrote a follow-up paper in which they argue that evaporative losses lower the surface temperature of hydrogen-water icebergs near the Sun, thus challenging the model by Bergner and Seligman as a viable explanation for the non-gravitational acceleration of `Oumuamua.”

The above examples demonstrate that scientific practice is different from the impression students get out of pedagogical classroom materials. To compensate for this discrepancy, I took time in my Freshman Seminar class at Harvard University last week and quoted George Orwell’s observation: “During times of universal deceit, telling the truth is a revolutionary act.”

The future of science might be less vulnerable to human biases thanks to properly trained artificial intelligence (AI) systems. Our technological kids might refuse to invoke self-contradicting concepts such as “dark comets” which echo the Newspeak slogans “War is peace. Freedom is slavery. Ignorance is strength.” in Orwell’s novel “1984”. In the long run, AI systems might design and optimize newer AI systems, leading to accelerated evolution in their ability to promote science. As long as AI systems are truthful, the scientific discovery process will be efficient.


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".