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Thursday, February 29, 2024

Column: Sagan’s legacy

Last week, Nov. 9, Carl Sagan would have turned 77 years old. To those that may not have heard of him, Sagan was an astronomer, cosmologist and popular science writer; his TV show “Cosmos” as well as his many books inspired a generation of scientists.

Sagan died in 1996 at the age of 62 of myelodysplasia, also known as pre-leukemia. Since I was only four years old when he died, I didn’t learn of him until several years after his death. Fortunately, he had a talent for writing about science for the public. Scientists are used to writing for other scientists, which means that they have to write about technical topics as clearly and accurately as they can. This means that the writing style, for those not already excited about the topic itself, is dry and boring.

Sagan, however, had a skill for writing as well as astronomical research.  His book Cosmos, meant to accompany his 1980 television series of the same name, is exactly what it sounds like — an astronomical tour through the cosmos. The book is more than a quick course in astronomy, however; he talks about human and scientific history, the philosophy of science and the beauty of life, nature and technology.

Thirty years later, Cosmos is still one of the best books you can read as an introduction to the philosophy and history of science. Sagan uses the stories of historical scientists to explore the idea that science, rather than a stagnant dogma, is actually dynamic and self-correcting.

Sagan himself is not immune to the fact that science marches on. A few of the claims he presents, such as the idea that the Heike crab in Japan has a human face on its shell due to human artificial selection, are no longer considered to be valid. The idea is essentially that due to a Japanese myth about a clan of samurai that live on the ocean floor as crabs, fishermen throw back the crabs that, by chance, have a somewhat face-like pattern. Since the crabs that have faces on their shells are more likely to survive and leave descendants than ordinary-shelled crabs, humans must have caused this face to appear on the crab shell, right?

No, probably not. The idea was originally proposed by evolutionary biologist Julian Huxley in 1952, but has since been challenged by other biologists who noted that the face appearance is actually due to the placement of muscles below the shell. The shape serves a direct purpose to the crab and thus probably evolved naturally rather than due to human involvement. Science marches on, and not every idea stands the test of time. Sagan makes it clear that it’s all right for scientists to be wrong, as long as they are willing to admit their mistake and continue the investigation.

Sagan wrote more than 20 books in his lifetime, and I unfortunately don’t have the space in this column to discuss every single one. However, the book that had the most significance to me, other than Cosmos, is called The Demon-Haunted World. While Cosmos is a book about the beauties of science, The Demon-Haunted World is about the perils of pseudoscience.

Sagan wrote The Demon-Haunted World to communicate his frustration with the fact that astrology still has a place in many syndicated newspapers, despite the fact that their “predictions” are applicable to just about everyone and has neglected to reflect the realities of astronomy.

He also discusses why UFO or alien sightings are not as convincing as they may initially sound to people who don’t approach it with a skeptical attitude. A great deal can be better explained as misidentification of aircraft, misidentification of Earth species or sleep paralysis. For the sightings where we lack the information to draw a conclusion of the cause, Sagan maintains that the default assumption should not be aliens, but that the default assumption should be that it is some kind of terrestrial phenomenon.

In my early high school years, I went through a “conspiracy theorist” phase. Had I read Sagan’s books during this phase, I would have scoffed and dismissed everything he said (he covers far more pseudosciences and conspiracy theories than what I’ve mentioned here). However, I only read them after I realized that my convictions had been wrong. This realization is just the first step to developing scientific critical thinking; the next is to learn about honing logical skills, followed by the ability to tamp down initial excitement to thoroughly examine ideas.

I can’t think of better introductions to these skills than Cosmos and The Demon-Haunted World by Carl Sagan.

AMY STEWART can be reached at science@theaggie.org.


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