The Skeptics Society & Skeptic magazine

According to the Harvard astronomer Avi Loeb, we have proof of alien existence, and more sightings are coming soon. In late 2017, scientists at a Hawaiian observatory glimpsed an object soaring through our inner solar system, moving so quickly that it could only have come from another star. Loeb argued that it was not an asteroid; it was moving too fast along a strange orbit and left no trail of gas or debris in its wake. There was only one conceivable explanation: the object was a piece of advanced technology created by an ancient alien civilization. This was a shocking claim, and many were vehemently opposed to Avi’s view. In his new book, and in this conversation, Loeb outlines his controversial theory and its profound implications for science, religion, and the future of our species and our planet. Also highlighted, and perhaps at the heart of his message, is Loeb’s plea for open and eager scientific inquiry into this field of study, and his calls for deeper faith in science and the breaking down of barriers between the scientific community and the non-scientific community.

Shermer and Loeb discuss:

• how to deal with anomalies in science in general and astronomy in particular, such as Tabby’s star, the light data from which was one thought to indicate the existence of ETI debris but now believed to be the result of natural causes,
• Galileo and Saturn and why he was wrong about this but right about the Copernican system,
• Signal Detection Theory: Face on Mars vs. Mt. Rushmore — one is due to natural erosion the other to intelligent design. What would convince Loeb’s colleagues that Oumuamua is ETI in origin?
• Before we say something is intelligently designed let’s first make sure it is not naturally designed.
• Carl Sagan’s influence on the scientific community to SETI,
• why Giordano Bruno was really burned at the stake (it wasn’t just because he believed in other worlds),
• the Law of Very Large Numbers and Oumuamua,
• How many unknown knowns are still out there in the form of comets & asteroids that could account for Oumuamua?
• the role of consensus among experts in science,
• What if the SETI Institute announced it had detected an ETI signal but it was degraded and anomalous and unclear whether it was natural or intelligent in nature, but they claimed it was?
• What if Kip Thorne announced LIGO discovered gravitational wave activity that suggests the collision of our universe with another universe, thereby confirming the multiverse theory, and then wrote a bestselling book about the aliens in this other universe?
• What will ETIs be like?
• Loeb’s response to theistic Cosmological and Fine-Tune arguments, and
• Why is there something rather than nothing?

Avi Loeb is the former chair of the astronomy department at Harvard University (2011–2020), founding director of Harvard’s Black Hole Initiative and director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics. He also chairs the Board on Physics and Astronomy of the National Academies and the advisory board for the Breakthrough Starshot project, and is a member of the President’s Council of Advisors on Science and Technology.

What follows is the passage from Dr. Shermer’s book The Believing Brain on Galileo and why he got Saturn wrong, discussed in the podcast as an example of what can happen if the data is degraded and there is no theory about what you’re observing.

Excerpt from The Believing Brain

After observing Saturn—the most distant planet of his day—through his tiny telescope, Galileo wrote to his astronomical colleague Johannes Kepler, “Altissimum planetam tergeminum observavi,” “I have observed that the farthest planet is threefold.” He then explained what he meant: “This is to say that to my very great amazement Saturn was seen to me to be not a single star, but three together, which almost touch each other.” He saw Saturn not as a planet with rings as we see it today in even the tiniest of home telescopes, but as one large sphere surrounded by two smaller spheres, thus accounting for its oblong shape.

Why did Galileo—champion of observation and induction—make this mistake? Having praised empiricism as the sine qua non of science, we must now admit its limitative effects. Galileo’s error is instructive for an understanding of the interplay of data and theory, and when it came to Saturn, Galileo lacked them both. Data: Saturn is twice as far away as Jupiter, thus what few photons of light there were streaming through the cloudy glass in his little tube made resolution of the rings problematic at best. Theory: There was no theory of planetary rings. It is at this intersection of nonexistent theory and nebulous data that the power of belief is at its zenith and the mind fills in the blanks. Like Columbus before him, Galileo went to his grave believing not what his eyes actually saw but what his model of the world told him he was seeing. It was literally a case of I wouldn’t have seen it if I hadn’t believed it.

Whenever the data of observation are unclear, the mind fills in the gaps. But if the mind has no model from which to work, imagination takes over, leading directly and powerfully to errors generated by expectation. Galileo could not “see” the rings of Saturn, either directly or theoretically, but he certainly saw something, and herein lies the problem. Altissimum planetam tergeminum observavi. As the late Harvard evolutionary theorist and historian of science Stephen Jay Gould noted in his insightful commentary on this affair: “He does not advocate his solution by stating ‘I conjecture,’ ‘I hypothesize,’ ‘I infer,’ or ‘It seems to me that the best interpretation…” Instead, he boldly writes ‘observavi’—I have observed. No other word could capture, with such terseness and accuracy, the major change in concept and procedure (not to mention ethical valuation) that marked the transition to what we call ‘modern’ science.”¹

Over time Galileo returned to Saturn often, and although he never saw the same thing twice, he stuck steadfastly with his original trigeminal observation and conclusion. As he wrote in his 1613 book on sunspots: “I have resolved not to put anything around Saturn except what I have already observed and revealed—that is, two small stars which touch it, one to the east and one to the west.” Challenged by a fellow astronomer who suggested that perhaps it was one oblong object rather than three spheres, Galileo boasted of his own superior observational skills, and that “where perfection is lacking, the shape and distinction of the three stars imperfectly seen. I, who have observed it a thousand times at different periods with an excellent instrument, can assure you that no change whatever is to be seen in it.”

The next time he pointed his tube to Saturn just before publication of his sunspot book, however, Galileo saw something rather different. “But in the past few days I returned to it and found it to be solitary, without its customary supporting stars, and as perfectly round and sharply bounded as Jupiter. Now what can be said of this strange metamorphosis?” What indeed? Recant the earlier observation? Perhaps, he wondered, “was it indeed an illusion and a fraud with which the lenses of my telescope deceive me for so long—and not only me, but many others who have observed it with me? … I need not say anything definite upon so strange and unexpected an event; it is too recent, too unparalleled, and I am restrained by my own inadequacy and the fear of error.”² Nevertheless, Galileo concluded in the 1613 sunspot book that despite this new data his original theory about what he saw was correct. Why? The answer may be found in the visual presentation of the data.

The great scholar of the visual display of quantitative information, Edward Tufte, notes in his 2005 book, Beautiful Evidence, with the accompanying page from Galileo’s 1613 sunspot book (see Figure 1), that “Galileo reported his discovery of Saturn’s unusual shape as 2 visual nouns that compare clear and murky telescopic views. In Galileo’s work Istoria e dimostrazioni intorno alle macchie solari (1613), words and images combine to become simply evidence rather than different modes of evidence.” The translation of the text in Figure 1 accompanied by the two tiny drawings of Saturn reads: “The shape of Saturn is thus ______ as shown by perfect vision and perfect instruments, but appears thus ______ where perfection is lacking, the shape and distinction of the three stars being imperfectly seen.” Tufte describes this sentence as “one of the best analytical designs ever” because it represented “Saturn as evidence, image, drawing, graphic, word, noun.”³ Despite his more recent observations that the “three stars” had become “solitary” and “as perfectly round and sharply bounded as Jupiter,” Galileo’s image, drawing, graphic, word, and noun were congealed into evidence that his original observations were correct. Galileo never fully retreated from his first definitive conclusion.

Figure 1. Galileo’s Saturn Evidence, Image, Drawing, Graphic, Word, Noun The page from Galileo’s 1613 book on sunspots, in which he returns to the consideration of the Saturn enigma, concluding once again that he was right in the first place that Saturn was a 3-bodied object. Source: Galileo Galilei, Istoria e Dimostrazioni Intorno Alle Macchie Solari (Rome, 1613), as reproduced in Edward Tufte, Beautiful Evidence (Graphics Press, 2006, p. 49)

The solution to the Saturn problem is equally instructive of the Data-Theory dialogue in the narrative of belief. It wasn’t until 1659—half a century after Galileo’s observations—that the Dutch astronomer Christiaan Huygens published the solution in his great work Systema Saturnium, one of the finest visual displays of both data and theory in the history of science. In Figure 2 we see on display thirteen interpretations of Saturn produced by astronomers from 1610 (Galileo) to 1645 (Fontana and others), all wrong.

Figure 2. Christiaan Huygens’ Catalogue of Errors The Dutch astronomer Christiaan Huygens solved the Saturn enigma in his 1659 work Systema Saturnium, in which he included this visual catalogue of the 13 most prominent theories of Saturn, including: I. Galileo, 1610; II. Scheiner, 1614; III. Riccioli, 1641 or 1643; IV–VII. Hevel, theoretical forms; VIII–IX. Riccioli, 1648–1650; X. Divini, 1646-1648; XI. Fontana, 1636; XII. Biancani, 1616; Gassendi, 1638, 1639; XIII. Fontana and others, 1644, 1645.

To our Data-Theory duo we should add Presentation of the data and theory. In many ways, presentation is everything in understanding of how beliefs are born, reinforced, and changed because humans are so visually-oriented as primates who once depended on three-dimensionality to navigate through dense arboreal environs. The Data-Theory-Presentation trialogue is on exquisite display in Figure 3, in which Huygens takes those two-dimensional Saturns, blows them up into 3-D, and puts them in motion around the sun. It is a marvelous presentation of both data and theory, incorporating Copernicus’s theory that the sun is at the center of the solar system instead of the earth (as in Ptolemaic cosmology), Kepler’s first law that planetary orbits are elliptical instead of circular (as in Aristotelian cosmology), and Kepler’s third law that the inner planets revolve around the sun faster than the outer planets.

Here we see the Sun-Earth-Saturn system from above—an Archimedian point outside the solar system that grants a new perspective—with Saturn set in motion on its glacially slow orbit of 29.5 Earth-years long, such that about 1.8 Earth-years elapse between each of the 32 Saturns in the diagram. The effect is to show that Saturn will appear different to Earth-bound observers at different times of the Earth year, thereby explaining why in the course of half a century so many keen-eyed astronomers saw so many different Saturns, including a Saturn with no rings at all because twice each Saturn-year the rings appear edge on from Earth-bound observers. As Edward Tufte eloquently describes the power of this visual explanation: “Huygens presents a series of still images in order to depict motion. To resolve such discontinuous spatial representations of continuous temporal activity, viewers must interpolate between images, closing up the gaps. Imaginative and original, this display is a classic, an exemplar of information design.”⁴

Figure 3. Saturn in 3-D and in Motion The Data-Theory-Presentation trialogue is on exquisite display here, in which Huygens takes those two-dimensional Saturns and blows them up into 3-D and puts them in motion around the sun. It is a marvelous presentation of both data and theory, incorporating Copernicus’s theory that the sun is at the center of the solar system instead of the earth (as in Ptolemaic cosmology), Kepler’s first law that planetary orbits are elliptical instead of circular (as in Aristotelian cosmology), and Kepler’s third law that the inner planets revolve around the sun faster than the outer planets.

The Saturn enigma and its ultimate solution reveals the interplay between data, theory, and presentation, between induction, deduction, and communication, between what we see, what we think, and what we say. We cannot untangle the three, for the mind engages them all to produce knowledge on which we act in the world. The Saturn affair demonstrates, in the master rhetorician Stephen Jay Gould’s words, both “the power and poverty of pure empiricism.” How? Gould’s answer is one of the most eloquent ever penned on this contentious issue:

The idea that observation can be pure and unsullied (and therefore beyond dispute)—and that great scientists are, by implication, people who can free their minds from the constraints of surrounding culture and reach conclusions strictly by untrammeled experiment and observation, joined with clear and universal logical reasoning—has often harmed science by turning the empiricist method into a shibboleth. The irony of this situation fills me with a mixture of pain for a derailed (if impossible) ideal and amusement for human foibles—as a method devised to undermine proof by authority becomes, in its turn, a species of dogma itself. Thus, if only to honor the truism that liberty requires eternal vigilance, we must also act as watchdogs to debunk the authoritarian form of the empiricist myth—and to reassert the quintessentially human theme that scientists can work only within their social and psychological contexts. Such an assertion does not debase the institution of science, but rather enriches our view of the greatest dialectic in human history: the transformation of society by scientific progress, which can only arise within a matrix set, constrained, and facilitated by society.⁵

Four centuries after Galileo changed the geography of knowledge of the world and its immediate environs in space, in the 1920s a cosmological matrix of data, theory, and presentation came together in a new cosmological pattern that completely changed the way we view the cosmos and our place in it. As bold a pattern-shatterer as he was, Galileo could never have imagined just how inconceivably vast and vacuous the heavens would turn out to be. How that new pattern was discovered, delineated, doubted, debated, and ultimately determined to be correct provides us with a final example of how science works to adjudicated disputes over conflicting patterns.

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