I’m going to be honest: most courses you take in university aren’t worth a whole lot. That’s not because the professors are bad or the coursework is pointless (although sometimes that is definitely the case). I mean that most of the courses you take will never be all that relevant to the rest of your life.
But then, every once in a while, often by accident, you stumble into a course that is hugely impactful on your life. That happened to me in my sophomore year. I needed to take an elective from the humanities department, and not wanting to get sucked into a seminar on “Romantic literature of the 1840s” or whatever, I went for the least humanities-sounding thing I could find on the list: a philosophy course called “Logic and Reasoning.” It probably ended up being the most valuable course I ever took in my life.
From day one, I loved my logic course. Each morning, we’d all come into class to find a question like this on the board:
“Every time a train arrives at the station, there are many passengers on the platform. You arrive at the station and see many passengers waiting on the platform. Is it necessarily true that a train will arrive soon?”
Pretty much everyone in the class would answer “yes” and then become infuriated when the professor told us the correct answer was no—just because trains always arrive when there are many passengers does not mean that many passengers will always result in a train arriving.
I don’t think I’ve ever seen so many pissed off twenty-year-olds as I did in that classroom each week. Many would accuse the professor of making shit up to humiliate them and give them poor grades. Others simply couldn’t follow what was going on, struggling to follow the steps in reasoning between “people,” “train,” and “time.” But I loved it.
Despite the outrage, the professor was demonstrating some of the most fundamental principles of thinking:
- Just because two things often occur together does not mean that they will necessarily always occur together.
- Just because a line of reasoning is intuitive does not mean it’s correct—logic can often be counterintuitive.
Logic is the bedrock of pretty much all human knowledge. As such, philosophers have killed many trees over the centuries, analyzing and determining the principles that define logic and reason. Their ambition has been to determine what we can know to be true and what we cannot know to be true.
What most people don’t realize is that logical fallacies—that is, errors in judgment and reasoning—are incredibly common in day-to-day life. Worse, we’re mostly unaware of how they disrupt and harm our lives, often in profound ways. These fallacies are right in front of our noses, yet we are so comfortable with our own thought processes that we fail to spot them.
This article will take you through some of the most common logical fallacies. It will teach you how to not only spot them in yourself but also how to spot them in others.
Table of Contents
1. Correlation Is Not Causation
Let’s start with probably the most important fallacy to understand—the one you and I and everyone we know fucks up with abandon: correlation is not causation. Just because two things regularly occur together does not mean one causes the other.
Let’s pretend for a second that today, I ate some ice cream and you lost your job. And what’s crazier is that the last time I ate ice cream, somebody else lost their job. Would you then say that me eating ice cream causes people to lose jobs? (If so, this would be one strange superpower.) Or would you simply say these are two common occurrences that happen to be occurring together for a short period of time?
You’d say the latter.
Yet, you’d be surprised how often this sort of thing gets passed off as “news” in the world.
Yet, when you dig into the data, the researchers found correlations—ice cream and job losses—and not causation.
Anxiety and depression increased and social media usage increased. That doesn’t mean one caused the other. It could be a coincidence. There could be some mysterious third force causing both to happen. The arrow of causation could point the other direction (e.g., people are becoming more depressed, so they retreat to social media more often to feel better).
Two things occurring together does not tell us much about whether one caused the other.
This is a huge problem in academic research. Scientists frequently present data in a way that suggests causation when all they found is a correlation. And even if they don’t present it that way, journalists will often take correlational data and write about it as if it’s causative.
The fact is, so much stuff happens at the same time and we have no idea why. You could argue that almost any correlation looks like causation if you wanted to. In fact, there’s a website called Spurious Correlations that does just that.
For example, here’s the correlation between Nicolas Cage movies and deaths caused by drowning in a pool:
Here’s cheese consumption and the number of people who were killed by their bedsheets:
But my favorite one is probably the correlation between the divorce rate in Maine and the per capita consumption of margarine:
Some day there’s going to be a politician in Maine shouting, “We can no longer let our families be destroyed by margarine!” Just you wait.
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2. Slippery Slope Fallacy
Stop me if you’ve ever heard this line of reasoning before:
“We can’t let teenagers drink alcohol because if they drink alcohol, then they’ll start doing drugs, and if they do drugs then they’ll become criminals. And if they become criminals, then they’ll end up in prison and ruin their lives. Therefore, allowing teenagers to drink alcohol will ruin their lives.”
The slippery slope fallacy is when you take one mild negative consequence and tie it with a similar but extreme negative consequence and then argue that one will lead to the other. You see this fallacy show up in all sorts of places, especially within business organizations, foreign policy, and yes, paranoid parenting.
The truth is that some but not all kids who drink alcohol do drugs. Some but not all kids who do drugs become addicts. Some but not all addicts become criminals. Some but not all criminals ruin their lives. Therefore, it is logically inaccurate to compare drinking alcohol with ruining a life.
(Not to mention, the data that shows that teenagers who drink alcohol are X times more likely to do drugs could be another case of “correlation is not causation.”)
The Slippery Slope Fallacy often fucks us up because it generates a lot of unnecessary fear and anxiety. We mess up an assignment at work. The boss gets mad. You start thinking, “Well if the boss is mad, then she’s going to hate me. And if the boss hates me, then I’m going to get fired. And if I get fired, then I’m going to be homeless. OMG I DON’T WANT TO BE HOMELESS!!!”
Calm your shit, buck-o. There are a lot of steps between a TPS Report and homelessness.
3. False Dichotomies
There are some classes of arguments where there are legitimately only two options. For instance, I could say, “There are two kinds of people in this world: people named Ron and people not named Ron.” This is a true dichotomy (or division of two): you’re either named Ron or you’re not.
But a false dichotomy is when a set of options is presented as if only two possibilities exist but in reality, many more exist.
For example, if I said, “There are only two kinds of people in the world: people named Ron and fucking idiots.” This is a false dichotomy. Why? Because these two options don’t encompass all potential options.
There are plenty of people not named Ron who are also not idiots. Also—and I can tell you this from experience—there are plenty of people named Ron who are total fucking idiots.
False dichotomies are used to manipulate people into allying with the speaker. You often hear politicians or other leaders say, “You’re either with us or against us,” as a way to whip people into line. But this is a false dichotomy. You could be indifferent. You could be partially with them and partially against them. You could be against everybody. Don’t buy into this bullshit.
But false dichotomies often hurt us when we judge ourselves. We often say things to ourselves like, “If I worked harder, I wouldn’t be such a loser.” You know you can be a loser who works hard, right? You can also not be a loser and not work hard, too. In fact, being a loser and working hard are completely arbitrary things that you just decided to force into a false dichotomy.
Why? To feel like shit about yourself. Now, why would you do that? I bet your name is Ron…
4. Begging the Question
Begging the question occurs when someone’s argument relies upon its own assumptions to make its case. For example:
- Everything in the Bible is true. Why? Because in the Bible, it says that everything in it is true.
- My husband always knows what’s right for me. Why? Because he told me that he always knows what’s right for me and he’s always right, so…
- Carl is a dork. Why? Because he tries to pretend he’s not a dork, so that makes him a dork.
This is often called “circular reasoning” because if you follow the logic, it leads you in a circle.
But similar to the fallacies above, begging the question can be subtle as well.
For example, I once got in an argument with an anarchist about politics (never recommended, by the way). He said that any organization that commits violence and wields influence over the population is inherently evil. Well, when you boil it down, part of the function of any government is to monopolize violence and wield influence over the population (ideally, for the benefit of all). I spent the better part of ten minutes trying to explain to this guy that he was simply restating the same belief over and over, yet, as you can imagine, it didn’t really go anywhere.
5. Red Herrings
Red Herrings are arguments that seem relevant to an issue but actually are not. For example, we could be arguing about whether being vegetarian is more ethical than eating meat. Then, in the middle of a perfectly fine argument, I blurt out, “Well, Hitler was vegetarian! And he surely wasn’t ethical!”
This is a distraction from the real point of debate: whether eating meat is inherently unethical. These kinds of distractions from the argument are known as “red herrings.” And if you—god forbid—spend lots of time watching and reading the news, you will notice a large proportion of what is said and written is some form of a red herring.
Red herrings are also usually logical fallacies themselves. For example, the assumption that because Hitler was vegetarian, and Hitler was unethical, vegetarianism must be unethical is known as the Fallacy of Composition—when something that is true for a part is assumed to be true for the whole (i.e., Paul is American and he is short, therefore Americans must be short).
Red Herrings are often used by people to divert blame away from themselves.
You: “Jon, you stole my bike.”
Jon: “Property is just a social construct, you didn’t really lose anything. After all, you have money for a new one.”
You: “Money isn’t the point, you fucking stole from me!”
Jon: “Millions of things get stolen every day, I don’t understand why you’re so upset it happened to you.”
You: “BECAUSE IT’S WRONG! YOU FUCKING STOLE MY SHIT!!!”
Jon: “Wow man, you’ve clearly got some anger problems going on here. You know, I don’t think I want to deal with someone who is so angry all the time. I’m going to bike home now.”
(We all know a Jon… don’t be friends with a Jon.)
6. Appeals to the Bandwagon, Authority, and Pity
When in an argument, it’s tempting to skip the logic and go straight to appealing to some outside source to make your point feel more resonant.
Well, unfortunately, logic doesn’t give a shit about your feelings. A bad argument is a bad argument, regardless of who agrees with you.
There are three common appeals that people make when trying to win points for their side:
- An appeal to authority: “Well, the president said it’s true, so it must be true!”
- An appeal to pity: “I know the data says that social media isn’t the problem, but these poor kids have so much anxiety, we should still get rid of their phones.”
- An appeal to the majority: “Everyone I know says that vaccines are dangerous, so it must be true.”
The hyper-social nature of our species causes us to appeal to outside influences. We all want to belong to a community. We all want to associate with high-status people. We all want others to know we’re kind and considerate.
The problem is that none of these things have anything to do with logic or truth. If something is true, it’s true whether anyone believes it or not.
At the end of the day, the truth doesn’t give a shit about you or me or anyone else. We care. And because we care we trick ourselves into thinking that these opinions affect the truth when they don’t.
7. Ad Hominem
Remember when you were a kid and you’d get in an argument with another kid, and they’d point out how you were wrong, and at a complete loss of how to defend yourself, you’d blurt out, “Well you’re just a smelly goat-face! And I don’t listen to smelly goat-faces,” and stomp off as if that solved something?
Yeah, that’s an ad hominem fallacy.
Sometimes, rather than attack someone’s argument, we just attack the person instead. You see this all the time in politics. Senator X wants to reform education. Senator Y doesn’t. But instead of arguing against Senator X’s proposals, Senator Y just calls Senator X a smelly goat-face. Voters cheer. Senator Y wins re-election. Democracy continues on as planned.
Sadly, the Ad Hominem Fallacy seems to be the fallacy of choice in political discourse and much of journalism these days. Political opponents rarely seem to be able to debate issues without launching personal attacks on one another that have nothing to do with the argument at hand.
8. Straw Man
If the Ad Hominem Fallacy is the bread and butter of politicians, then the Straw Man Fallacy is the bread and butter of social media.
Rather than debating a claim based on its merits, we sometimes substitute a distorted, exaggerated, or otherwise ridiculously misrepresented version of the argument to more easily attack it.
This is called the “straw man” fallacy because, like replacing a real person with a person made of straw, you’re replacing a stronger argument with a weaker one in order to more easily discredit it.
Straw men arguments are quite common—and shockingly dumb:
- “You’re pro-choice? So you enjoy killing babies, I see.”
- “You want to reduce the defense budget? You must hate the military and don’t support our soldiers.”
More subtle examples of the straw man argument are quite common too. For instance, someone might argue that we should work to reduce the prison population by enforcing more lenient punishments for non-violent drug offenses. A subtle but common straw man counterargument is that such a view is “soft on crime.” This distorts the original argument by implying that all crimes should be punished more leniently when the real argument is that some drug crimes don’t warrant prison time.
The real damage of the straw man fallacy isn’t necessarily that it’s wrong—it’s that it distracts everyone horribly from the real issue at hand. People spend the entire time defending their beliefs from ridiculous characterizations and no one actually talks about the real issues.
The Importance of Sound Reasoning
If you haven’t noticed, we all kinda suck at this logic and reason thing. This list is just a tiny slice of the logical fallacies pie but probably accounts for a significant portion of what we think and are exposed to each day.
But that doesn’t mean we shouldn’t make every effort to be better. After all, logic and reason are our life preservers in a vast sea of uncertainty and bullshit. To let go of the life preserver, to cling onto the latest, greatest fad or the dipshit who’s currently on your screen… well, that’s intellectual suicide.
Not to mention that a lot of these logical fallacies can turn you into an insufferable dick pretty quickly. Debating with someone over the merits of an idea or argument is already contentious enough. But falling into the trap of these logical fallacies, many of which hinge on making a mockery of the other person’s ideas (or the person themselves), will not make you the biggest hit at children’s parties. Not to mention people won’t exactly be thrilled to talk to you about anything important or meaningful.
At best, fallacious reasoning keeps bad ideas alive. At its worst, it pits us against each other in a hopeless downward spiral of tit-for-tat where nobody really wins and everyone definitely loses.
Logical reasoning isn’t about “winning” an argument. It’s about finding the truth. And inevitably, getting closer to truth requires one to recognize and admit when they’re wrong. And that’s something you, me, and all the Rons of the world could be a bit better at.