12 Common Logical Fallacies and How to Debunk Them
These false arguments infect our conversations, advertising, social media and the big screen. Here's what to look for.
12 Common Logical Fallacies and How to Debunk Them
If you’ve ever gotten lost in an argument or discussion, it’s probably because there are too many things going on, from messy emotions to persuasion tactics.
Information overload and logical fallacies find their ways into more than day-to-day conversations — it is ingrained in advertising, social media and the big screen. They appear in the subtlest of ways to the most discernible, in the form of political speeches to advertising campaigns.
Winning or losing an argument is one thing, but understanding the quality and validity of a claim is another. It often feels like we have to convince the other person or other side to see our side in discussions, but actually understanding a logic also helps us see through faulty arguments and become a better judge of different ideas and views.
Here are some of most common logical fallacies and some ways to dissect them.
Ever been in a fight and catch yourself attacking the other person, rather than focusing on the content of the argument? It happens.
“Ad hominem” is Latin for “to the man or person,” and in this situation refers to one person attacking the other in order to advance an argument.
“Friends” fans know this kind of banter well. Disagreements typically end in one of the friends making fun of Monica’s former fat self and her high-maintenance habits, or with someone teasing Ross for his paleontology rants and failed marriages.
This kind of fallacy is best combated by focusing on the logic and validity of an argument, instead of making it about the person. Separate the claims from the person making them.
Appeal to Authority
This kind of logical fallacy arises when one party insists something is true just because an authority or expert said it.
In a time when Instagram celebrities and movie stars can boast more followers and have more sway than scientists or industry experts, it’s easy to fall prey and believe a claim to be true because somebody of influence said or supported it.
Even experts in their own fields don’t always agree on the evidence for an argument. For example, someone can claim a diet they heard on Dr. Oz’s show really works to burn fat. Dr. Mehmet Oz, an American cardiothoracic surgeon, author and television personality, has a strong following and authority when it comes to topics on health and nutrition.
In fact, Dr. Oz once talked about a garcinia extract, or a kind of hydroxycitric acid found in fruits, as the new fat-fighting tool. Yet the extract didn’t come with much evidence to prove it was an effective weight-loss tool. A study from years before Dr. Oz talked about the supplement on national television found that garcinia cambogia performed no better than a placebo for weight loss in a trial of 135 people.
Bandwagon Argument, or Ad Populum
The saying “jumping on the bandwagon” pretty much sums this up. The bandwagon argument describes when someone makes a claim or supports a cause because it is the popular choice.
It assumes a proposition is true because most people believe it, but we’ve been debunking popular claims for centuries.
Millions once believed the Earth to be flat and motionless, and that the Earth was the center of the universe. Of course, the geocentric model was a limited observation that was later proved false by people like Nicolaus Copernicus, Johannes Kepler and Galileo Galilei, who argued instead the sun was at the center.
Creating a strawman means to misrepresent your opponent’s argument because it is easier to attack compared to his or her actual argument. It’s essentially creating an easier target so that it can be knocked down to support your own idea.
This can happen easily in political debates sometimes, when, for instance, one side claims that those who don’t support a state minimum wage increase hate the poor. In this case, one side says the other’s position makes him or her an enemy of the poor, but by doing so oversimplifies the point.
President Richard Nixon’s "Checkers" speech in 1952 is a classic example of putting up a strawman: When his critics accused him of taking money illegally from election campaigns, the president countered by addressing a different gift he got from supporters — a black and white cocker spaniel that his daughter named Checkers. His distraction seemed to work in drawing attention away from the campaign funds, and he and Dwight Eisenhower were later elected by a landslide.
Arguments can sometimes go around in circles and appear to go nowhere. This frustrating feeling generally develops when it feels like the other person may be restating an argument rather than trying to prove it.
It’s like saying, “We need to cut prison spending, because too much money is being spent,” or “Trump is a good communicator because he gives effective speeches.” The argument and the evidence used in these cases are one and the same.
To avoid circular arguments, the author can instead provide actual, supportive evidence, such as Trump’s use of language or ability to explain complex issues.
The Genetic Fallacy
This happens when we make a conclusion based on the origins of a person or an idea. It supersedes argument by focusing on the nature or character of someone or something rather than presenting a case that explains why the argument is problematic.
For example, the genetic fallacy can entail viewing a public school teacher’s claims about the public school system as false and biased, or believing that an overweight doctor cannot have anything valid to say about health and fitness.
It is fallacious to support or shut down an idea or person based on its past or merits, unless that history actually has to do with the present. To steer clear of genetic fallacies, avoid evaluating argument based on irrelevant history.
Anecdotes come from personal experience, and while understanding our experiences is great, it doesn’t always strengthen an argument. Sure, it can be convincing and add color to your conversation, but generalizing one person’s experience to a mass typically is not very compelling evidence.
Romcom viewers might remember a particular scene at the beginning of “He’s Just Not That Into You,” in which Gigi, one of the protagonists, used anecdotal evidence to explain why guys who cheat on their girlfriends do not actually care about them.
According to Gigi, her friend Anastasia dated a guy who cheated on her, but then he changed and the couple lived happily ever after. Anastasia was an exception to the rule that men who cheat do not care about their partners, but Gigi’s own experience dating a guy who cheated on her did not yield the same happy ending.
Therefore, Gigi concludes that she and her female friends are the rule, rather than the exceptions, and that they should stop believing these stories about men who cheat and the hope that, despite the infidelity, they will end up in happy relationships.
Gigi’s anecdotes, while convincing, may not apply to all women with unfaithful partners.
Appeal to Emotion
Arguments and debates usually involve a lot of complex feelings and emotions. In this fallacy, the person is manipulating emotions in order to get acceptance for his or her claim, as opposed to using logical evidence or a valid argument.
It’s easy to feel pity or compassion when your opponent is down, because most people are affected by emotions.
Parents employ this tactic often with their young ones: We’re always reminded of the starving children in a third-world country when refusing to finish the steamed vegetables.
The Slippery Slope
This fallacy results from a lot of assumptions, namely that if event "A" occurs, then event "Z" will follow. Therefore, the person might argue, event A should not occur to prevent sliding down the slope of subsequent negative events.
The slippery slope fallacy focuses on probability and hypotheticals, rather than looking at the task at hand.
Before the U.S. legalized gay marriage in all 50 states, some critics of same-sex marriage suggested that if we allowed gay marriage, we would open the gate to people someday marrying their dogs or horses.
That became a slippery slope argument to assume that Americans might want to marry their pets just because they can now marry their same-sex partners. Don’t make sweeping conclusions.
Tu qouque in Latin translates to “you too,” and this fallacy occurs when one side engages in criticism with criticism.
Similar to the ad hominem fallacy, one side will turn the argument or criticism back to the accuser, without addressing the original argument.
It’s easy to counter an argument by finding something else to criticize. Sibling rivalries, political debates and bickering couples often fall prey to this fallacy.
One person might say that killing animals for clothing or food is wrong, yet the other may criticize that he or she eats beef and wears leather jackets. By attacking Person A’s food and fashion preferences does not actually have anything to do with the logic that using animals for food and clothes is bad. Keep the focus on why or why these actions may be wrong.
The Middle Ground
It’s easy to settle for the middle. The middle ground fallacy says that a person can claim that a compromise or middle ground between two extremes has to be true.
While this can be valid in some cases, this fallacy causes us to think that there must be some truth in between or in a shade of grey. Sometimes, the halfway point of a truth and a lie is still a lie.
Maybe one politician wants to deport all illegal immigrants, while another believes in giving them full citizenship. Does that mean developing a process to citizenship, in which illegal immigrants must earn citizenship, rather than deportation or amnesty must be the right approach?
Or maybe two people are debating the color of the sky. Jack says the sky is blue and Jill says it’s red, but the sky is definitely not purple.
The Gambler’s Fallacy
It turns out gambling happens outside of casinos all the time. In our minds, a gambler’s fallacy happens when we mistakenly think separate, independent events can affect the likelihood of another random event.
We sometimes get tricked into seeing streaks as having an affect on statistically independent events — the same way we think about flipping a coin, which has a one in two chance of landing heads or tails up.
If the coin lands ten times in a row heads up, the gambler might think that it will land tails up on the next flip. The odds of 50/50 actually are the same, because each flip is independent of the last.