Carl Sagan's 1988 astronomy course had nothing to do with stars. The final exam is still relevant.
"He knew critical thinking was a skill needed to tackle the world's problems."

Carl Sagan's Astronomy 490 class had little to do with astronomy, at least on the surface.
If you signed up for a college class called Astronomy 490, you'd likely expect it to be a high level study of the cosmos. It would focus on stars, planets, galaxies, black holes, perhaps delving deeper into theories of the world's greatest astrophysicists and cosmologists. Something having to actually do with the night sky at least, right?
Famed astronomer and science communicator Carl Sagan offered Astronomy 490 at Cornell University as a senior seminar course in the 1980s, but it was nothing like what one might expect. The focus of the course wasn't stars, but "critical thinking in scientific and non-scientific contexts." The course used examples from Astronomy and other fields and case studies from the history of science as well as "borderline science and medicine, religion and politics." The idea was to help students across all fields of study to become better thinkers through logic and rhetoric and the scientific method.
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Students had to be approved by Sagan in order to take the class, and they had to be "well-qualified" and prepared to "assimilate an extensive reading list" as well as participate in class discussions. The book list included textbooks on logic, reasoning, cooperation, and free thought, and class discussion topics ranged from world hunger to Affirmative Action to the Palestinian state.
The Library of Congress houses Sagan's handwritten course notes, which special curator and digital archivist Trevor Owens wrote, "include mention of the important balance between openness to new ideas and skeptical engagement with those ideas in science" and show how "he wanted to use student’s every day experience with things like television to prompt them to think more skeptically about how claims are made and warranted in everyday life."
Critical thinking became even more important in the age of television. Giphy
But what was perhaps most interesting about the course is its final exam. Or rather, exams. The Library of Congress has course exams from 1986 and 1988, and they differ in what Sagan asked students to do. However, the purpose was the same: To prompt students to put to use all the critical thinking skills they had gained in the class.
In his 1986 final exam, Sagan asked students to do two thought exercises and write papers about them. The first was to comment on the pros and cons of this quote from George Bernard Shaw, written around 1921:
"Our credulity, though enormous, is not boundless; and our stock of it is quite used up by our mediums, clairvoyants, hand readers, slate writers, Christian Scientists, psycho-analysts, electronic vibration diviners, therapeutists of all schools registered and unregistered, astrologers, astronomers who tell us that the sun is nearly a hundred million miles away and that Betelgeuse is ten times as big as the whole universe, physicists who balance Betelgeuse by describing the incredible smallness of the atom, and a host of other marvel mongers whose credulity would have dissolved the Middle Ages in a roar of sceptical merriment. In the Middle Ages people believed that the earth was flat, for which they had at least the evidence of their senses: we believe it to be round, not because as many as one per cent of us could give the physical reasons for so quaint a belief, but because modern science has convinced us that nothing that is obvious is true, and that everything that is magical, improbable, extraordinary, gigantic, microscopic, heartless, or outrageous is scientific."
First page of Carl Sagan's Astronomy 490 final exam in 1988.Library of Congress
The second part of the exam was to design and execute an experimental test of sun sign astrology (such as the daily horoscopes in the newspapers of the time). If that experiment found that evidence for sun sign astrology was poor, students were to explain its popularity. If the experiment found that evidence for sun sign astrology was fair, good, or excellent, students were to explain the scholarly disdain for it. In other words, they had to make the argument against whatever their experiment results were.
In the 1988 exam, students were asked to read "When Prophecy Fails," a short book about a UFO cult known as Clarionites (also Seekers) in the 1950s that had predicted that the end of the world would happen on December 21, 1954. Researchers followed the group to see what would happen when their predicted apocalypse didn't happen.
Sagan asked students to imagine they were part of that research team, but altered the scenario in two ways—adding a new charismatic leader rising up among the Clarionites and some natural disasters occurring on December 21, 1954.
sci-fi ufo GIF Giphy
Then he asked the students to do the following:
- Describe your best estimate of what might have happened as a result of these altered events over the next few years, informed by our readings and class discussions, including the Milgram experiments. [The Milgram experiments tested people's willingness or unwillingness to follow authority when it meant harming other people.]
- Compose a dialogue, taking place 34 years later (i.e.,now) between a believer in Clarionite intervention and a skeptic, making the best case possible for both points of view.
- What lessons, if any, can we draw?
Sagan clarified that there was no correct answer to either of the exam assignments. He simply wanted to see the students' critical thinking in action and for them to show what they'd learned with "coherency and cogency of argument."
Second page of Astronomy 490 final exam from 1988.Library of Congress
What stands out about these exams is that they ask the students to make arguments on both sides of a controversial topic. After all, critical thinking isn't just about being skeptical or rejecting ideas in the name of science; it's also about being able to understand and construct the arguments someone would make on any side of an issue. If you understand someone's arguments well enough to create them yourself, they become much easier to deconstruct and point out the elements that don't makes sense.
In a time when people have a hard time agreeing on basic facts, conspiracy theories abound, expertise is under attack, and prejudices of all kinds easily cloud people's judgment, perhaps we can take Sagan's final Astronomy 490 goals to heart and work on sharpening our critical thinking skills.