The following common informal logical fallacies are verbatim from an article published by The Best Schools. I highly recommend checking out their website if you’re looking to attend college or university in America and need a bit of guidance or further research. This article is part two, click here to read part one.

Red Herring Fallacy (ignoratio elenchi)

A red herring fallacy can be difficult to identify because it’s not always clear how different topics relate.

A “red herring fallacy” is a distraction from the argument typically with some sentiment that seems to be relevant but isn’t really on-topic. This tactic is common when someone doesn’t like the current topic and wants to detour into something else instead, something easier or safer to address. A red herring fallacy is typically related to the issue in question but isn’t quite relevant enough to be helpful. Instead of clarifying and focusing, it confuses and distracts.

The phrase “red herring” refers to a kippered herring (salted herring-fish) which was reddish brown in color and quite pungent. According to legend, this aroma was so strong and delectable to dogs that it served as a good training device for testing how well a hunting dog could track a scent without getting distracted. Dogs aren’t generally used for hunting fish so a red herring is a distraction from what he is supposed to be hunting.

A red herring fallacy can be difficult to identify because it’s not always clear how different topics relate. A “side” topic may be used in a relevant way, or in an irrelevant way. In the big meaty disagreements of our day, there are usually a lot of layers involved, with different subtopics weaving into them. We can guard against the red herring fallacy by clarifying how our part of the conversation is relevant to the core topic.

Tu Quoque Fallacy

The “tu quoque,” Latin for “you too,” is also called the “appeal to hypocrisy” because it distracts from the argument by pointing out hypocrisy in the opponent. This tactic doesn’t solve the problem, or prove one’s point, because even hypocrites can tell the truth. Focusing on the other person’s hypocrisy is a diversionary tactic. In this way, using the tu quoque typically deflects criticism away from yourself by accusing the other person of the same problem or something comparable. If Jack says, “Maybe I committed a little adultery, but so did you Jason!” Jack is trying to diminish his responsibility or defend his actions by distributing blame to other people. But no one else’s guilt excuses his own guilt. No matter who else is guilty, Jack is still an adulterer.

The tu quoque fallacy is an attempt to divert blame, but it really only distracts from the initial problem. To be clear, however, it isn’t a fallacy to simply point out hypocrisy where it occurs. For example, Jack may say, “yes, I committed adultery. Jill committed adultery. Lots of us did, but I’m still responsible for my mistakes.” In this example, Jack isn’t defending himself or excusing his behavior. He’s admitting his part within a larger problem. The hypocrisy claim becomes a tu quoque fallacy only when the arguer uses some (apparent) hypocrisy to neutralize criticism and distract from the issue.

Causal Fallacy

The causal fallacy is any logical breakdown when identifying a cause. You can think of the causal fallacy as a parent category for several different fallacies about unproven causes.

One causal fallacy is the false cause or non causa pro causa (“not the-cause for a cause”) fallacy, which is when you conclude about a cause without enough evidence to do so. Consider, for example, “Since your parents named you ‘Harvest,’ they must be farmers.” It’s possible that the parents are farmers, but that name alone is not enough evidence to draw that conclusion. That name doesn’t tell us much of anything about the parents. This claim commits the false cause fallacy.

Another causal fallacy is the post hoc fallacy. Post hoc is short for post hoc ergo propter hoc (“after this, therefore because of this”). This fallacy happens when you mistake something for the cause just because it came first. The key words here are “post” and “propter” meaning “after” and “because of.” Just because this came before that doesn’t mean this caused that. Post doesn’t prove propter. A lot of superstitions are susceptible to this fallacy. For example:

“Yesterday, I walked under a ladder with an open umbrella indoors while spilling salt in front of a black cat. And I forgot to knock on wood with my lucky dice. That must be why I’m having such a bad day today. It’s bad luck.”

Now, it’s theoretically possible that those things cause bad luck. But since those superstitions have no known or demonstrated causal power, and “luck” isn’t exactly the most scientifically reliable category, it’s more reasonable to assume that those events, by themselves, didn’t cause bad luck. Perhaps that person’s “bad luck” is just their own interpretation because they were expecting to have bad luck. They might be having a genuinely bad day, but we cannot assume some non-natural relation between those events caused today to go bad. That’s a Post Hoc fallacy. Now, if you fell off a ladder onto an angry black cat and got tangled in an umbrella, that will guarantee you one bad day.

Another kind of causal fallacy is the correlational fallacy also known as cum hoc ergo propter hoc (Lat., “with this therefore because of this”). This fallacy happens when you mistakenly interpret two things found together as being causally related. Two things may correlate without a causal relation, or they may have some third factor causing both of them to occur. Or perhaps both things just, coincidentally, happened together. Correlation doesn’t prove causation.

Consider for example, “Every time Joe goes swimming he is wearing his Speedos. Something about wearing that Speedo must make him want to go swimming.” That statement is a correlational fallacy. Sure it’s theoretically possible that he spontaneously sports his euro-style swim trunks, with no thought of where that may lead, and surprisingly he’s now motivated to dive and swim in cold, wet nature. That’s possible. But it makes more sense that he put on his trunks because he already planned to go swimming.

Fallacy of Sunk Costs

We are susceptible to this errant behavior when we crave that sense of completion or a sense of accomplishment.

Sometimes we invest ourselves so thoroughly in a project that we’re reluctant to ever abandon it, even when it turns out to be fruitless and futile. It’s natural and usually not a fallacy to want to carry on with something we find important, not least because of all the resources we’ve put into it. However, this kind of thinking becomes a fallacy when we start to think that we should continue with a task or project because of all that we’ve put into it, without considering the future costs we’re likely to incur by doing so. There may be a sense of accomplishment when finishing, and the project might have other values, but it’s not enough to justify the cost invested in it.

“Sunk cost” is an economic term for any past expenses that can no longer be recovered. For example, after watching the first six episodes of Battlestar Galactica, you decide the show isn’t for you. Those six episodes are your “sunk cost.” But, because you’ve already invested roughly six hours of your life in it, you rationalize that you might as well finish it. All apologies to Edward James Olmos, but this isn’t “good economics” so to speak. It’s more cost than benefit.

Psychologically, we are susceptible to this errant behavior when we crave that sense of completion or a sense of accomplishment, or we are too comfortable or too familiar with this unwieldy project. Sometimes, we become too emotionally committed to an “investment,” burning money, wasting time, and mismanaging resources to do it.

Appeal to Authority (argumentum ad verecundiam)

This fallacy happens when we misuse an authority. This misuse of authority can occur in a number of ways. We can cite only authorities — steering conveniently away from other testable and concrete evidence as if expert opinion is always correct. Or we can cite irrelevant authorities, poor authorities, or false authorities.

Like many of the other fallacies in this list, the argumentum ad verecundiam (“argument from respect”) can be hard to spot. It’s tough to see, sometimes, because it is normally a good, responsible move to cite relevant authorities supporting your claim. It can’t hurt. But if all you have are authorities, and everyone just has to “take their word for it” without any other evidence to show that those authorities are correct, then you have a problem.

Often this fallacy refers to irrelevant authorities — like citing a foot doctor when trying to prove something about psychiatry; their expertise is in an irrelevant field. When citing authorities to make your case, you need to cite relevant authorities, but you also need to represent them correctly, and make sure their authority is legitimate.

Suppose someone says, “I buy Hanes™ underwear because Michael Jordan says it’s the best.” Michael Jordan may be a spokesperson, but that doesn’t make him a relevant authority when it comes to underwear. This is a fallacy of irrelevant authority.

Now consider this logical leap: “four out of five dentists agree that brushing your teeth makes your life meaningful.” Dentists generally have expert knowledge about dental hygiene, but they aren’t qualified to draw far-reaching conclusions about its existential meaningfulness. This is a fallacy of misused authority. For all we know, their beliefs about the “meaning of life” are just opinions, not expert advice.

Or take the assumption that, “I’m the most handsome man in the world because my mommy says so.” Now, while I might be stunningly handsome, my mom’s opinion doesn’t prove it. She’s biased. She’s practically required to tell me I’m handsome because it’s her job as a mother to see the best in me and to encourage me to be the best I can be. She’s also liable to see me through “rose-colored glasses.” And, in this case, she’s not an expert in fashion, modeling, or anything dealing in refined judgments of human beauty. She’s in no position to judge whether I’m the most handsome man in the world. Her authority there is illusory (sorry mom).

There’s another problem with relying too heavily on authorities: even the authorities can be wrong sometimes. The science experts in the 16th century thought the Earth was the center of the solar system (geocentrism). Turns out they were wrong. The leading scientists in the 19th century thought that the universe as we know it always existed (steady state theory). They too were wrong. For these reasons, it’s a good general rule to treat authorities as helpful guides with suggestive evidence, but even authorities deserve a fair share of skepticism since they can make mistakes, overstep their expertise, and otherwise mislead you.

Equivocation (ambiguity)

Equivocation happens when a word, phrase, or sentence is used deliberately to confuse, deceive, or mislead by sounding like it’s saying one thing but actually saying something else. Equivocation comes from the roots “equal” and “voice” and refers to two-voices; a single word can “say” two different things. Another word for this is ambiguity.

When it’s poetic or comical, we call it a “play on words.” But when it’s done in a political speech, an ethics debate, or in an economics report, for example, and it’s done to make the audience think you’re saying something you’re not, that’s when it becomes a fallacy. Sometimes, this is not a “fallacy” per se, but just a miscommunication. The equivocation fallacy, however, has a tone of deception instead of just a simple misunderstanding. Often this deception shows up in the form of euphemisms, replacing unpleasant words with “nicer” terminology. For example, a euphemism might be replacing “lying” with the phrase “ creative license, ” or replacing my “criminal background” with my “youthful indiscretions,” or replacing “fired from my job” with “taking early retirement.” When these replacement words are used to mislead people they become an equivocation fallacy.

Appeal to Pity (argumentum ad misericordiam)

Truth and falsity aren’t emotional categories, they are factual categories.

Argumentum ad misericordiam is Latin for “argument to compassion.” Like the ad hominem fallacy above, it is a fallacy of relevance. Personal attacks, and emotional appeals, aren’t strictly relevant to whether something is true or false. In this case, the fallacy appeals to the compassion and emotional sensitivity of others when these factors are not strictly relevant to the argument. Appeals to pity often appear as emotional manipulation.

Truth and falsity aren’t emotional categories, they are factual categories. They deal in what is and is not, regardless of how one feels about the matter. Another way to say it is that this fallacy happens when we mistake feelings for facts. Our feelings aren’t disciplined truth-detectors unless we’ve trained them that way. So, as a general rule, it’s problematic to treat emotions as if they were (by themselves) infallible proof that something is true or false. Children may be scared of the dark for fear there are monsters under their bed, but that’s hardly proof of monsters.

To be fair, emotions can sometimes be relevant. Often, the emotional aspect is a key insight into whether something is morally repugnant or praiseworthy, or whether a governmental policy will be winsome or repulsive. People’s feelings about something can be critically important data when planning a campaign, advertising a product, or rallying a group together for a charitable cause. It becomes a fallacious appeal to pity when the emotions are used in substitution for facts or as a distraction from the facts of the matter.

It’s not a fallacy for jewelry and car companies to appeal to your emotions to persuade you into purchasing their product. That’s an action, not a claim, so it can’t be true or false. It would however be a fallacy if they used emotional appeals to prove that you need this car, or that this diamond bracelet will reclaim your youth, beauty, and social status from the cold clammy clutches of Father Time. The fact of the matter is, you probably don’t need those things, and they won’t rescue your fleeting youth.

Bandwagon Fallacy

The bandwagon fallacy assumes something is true (or right, or good) because other people agree with it. A couple different fallacies can be included under this label, since they are often indistinguishable in practice. The ad populum fallacy (Lat., “to the populous/popularity”) is when something is accepted because it’s popular. The concensus gentium (Lat., “consensus of the people”) is when something is accepted because the relevant authorities or people all agree on it. The status appeal fallacy is when something is considered true, right, or good because it has the reputation of lending status, making you look “popular,” “important,” or “successful.”

For our purposes, we’ll treat all of these fallacies together as the bandwagon fallacy. According to legend, politicians would parade through the streets of their district trying to draw a crowd and gain attention so people would vote for them. Whoever supported that candidate was invited to literally jump on board the bandwagon. Hence the nickname “bandwagon fallacy.”

This tactic is common among advertisers. “If you want to be like Mike (Jordan), you’d better eat your Wheaties.” “Drink Gatorade because that’s what all the professional athletes do to stay hydrated.” “McDonald’s has served over 99 billion, so you should let them serve you too.” The form of this argument often looks like this: “Many people do or think X, so you ought to do or think X too.”

One problem with this kind of reasoning is that the broad acceptance of some claim or action is not always a good indication that the acceptance is justified. People can be mistaken, confused, deceived, or even willfully irrational. And when people act together, sometimes they become even more foolish — i.e., “mob mentality.” People can be quite gullible, and this fact doesn’t suddenly change when applied to large groups.

The above is verbatim from an article published by The Best Schools. I highly recommend checking out their website if you’re looking to attend college or university in America and need a bit of guidance or further research. This article is part two, click here to read part one.

I’d love to know…

What fallacy do you most commonly experience in debate?

How many of these fallacies have you encountered?

What fallacy are you guilty of using?