Carl Sagan is remembered by many as the celebrated slightly-geeky astronomer who spoke of “millions and billions” of stars. But Sagan had another, more down-to-earth passion, a subject he studied almost as deeply as the cosmos: critical thinking.
Sagan understood that human beings have a hard time thinking right. In his writings, he listed and described the many mental traps and logical fallacies that can cause people to make faulty assumptions, poor judgments, and bad decisions. Sagan even came up with a set of sensible rules and guidelines—he called it his “baloney detection kit”—designed to help people think more clearly.
To Sagan, the stakes were high. As he told an interviewer in 1996, “If we are not able to ask skeptical questions . . . to interrogate those who tell us something is true, to be skeptical of those in authority . . . then we are up for grabs for the next charlatan, political or religious, who comes ambling along.”
Now the stakes are even higher
Today, decades later, Sagan’s words seem prescient. We have seen large swaths of people fall prey to conspiracy theories and “big lies” espoused by politicians, media figures, and others playing the role of Sagan’s ‘charlatan.’ And even in the larger population, among those not prone to extremist views or conspiracy thinking, there is widespread confusion about what’s true and who should be believed. One recent study found that 80 percent of students—from middle school all the way through college—could not judge the credibility of a news story on social media.
As Sagan knew, if citizens aren’t willing to think critically as they choose potential leaders, they’re apt to choose bad ones. And if they can’t judge whether the information they’re receiving is sound, they may follow bad advice while ignoring recommendations that are science-based and solid (and perhaps life-saving).
Moreover, as a society, if we can’t think critically about the problems we face, it becomes more difficult to reach a consensus on them (much less solve them). For that reason alone, critical thinking—that boring thing you heard about and ignored in high school—just might be the critical issue of our times.
So, what can Sagan teach us about critical thinking?
Sagan teaches us that we must be conscious of our own cognitive blind spots—and of the many ways we can fall prey to faulty thinking. When we encounter new information—whether it’s a news story, or a claim from a politician or an advertiser, or maybe something we’ve stumbled upon on the Internet—we must always be on the lookout for rhetorical “baloney,” as Sagan put it.
Sagan noted that bogus claims and arguments are often rooted in faulty logic. So the question to be asked is: Is this logical? Illogical arguments are not supported by sound reasoning; they tend to be based on fallacies and faulty assumptions. For example, a common fallacy is the slippery slope argument—wherein someone tries to convince you that it is risky to do some perfectly reasonable thing because it will surely lead to something much worse (e.g., one minor restriction will eventually lead to you losing all your rights!).
Sagan pulled together an invaluable list of more than a dozen of the most pernicious logical fallacies to watch out for in his “baloney detection kit,” which was first published as a chapter of his 1996 book The Demon-Haunted World: Science as a Candle in the Dark.
Here are some of the fallacies listed in Sagan’s book:
- Ad hominem attacks (which attack the arguer and not the argument).
- Argument from authority: meaning, we are being asked to trust what we’re being told because it’s coming from a very important person.
- Appeal to ignorance: the claim that “whatever has not been proved false must be true, and vice versa.”
- Begging the question: when an argument’s premises assume (without evidence) the truth of its conclusion.
- Non sequitur: Latin for “it does not follow,” in this case meaning a conclusion does not follow from the preceding argument.
- Slippery slope (described above).
- Straw man argument: “caricaturing a position to make it easier to attack.”
Sagan’s kit also offers up some “tools” for skeptical thinking, such as:
- “Wherever possible there must be independent confirmation of the facts.”
- Encourage debate from all points of view.
- “Spin more than one hypothesis.”
- “Try not to get overly attached to a hypothesis just because it’s yours.”
There’s plenty more in Sagan’s book, which I highly recommend. You can also read an excellent summary of Sagan’s ‘Baloney Detection’ chapter by Maria Popova, editor of site The Marginalian (formerly Brain Pickings). Popova’s site is where I (and many others, I’d wager) recently became aware of Sagan’s decades-old kit.
