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Some Common Logical Fallacies (and How They Corrupt Reasoned Debate)

Updated on April 17, 2017
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Catherine Giordano is a writer and public speaker who often writes and speaks on topics related to science, philosophy, and religion.

What Are Logical Fallacies?

In simple terms, logical fallacies are errors in reasoning which lead to false conclusions. If they go unrecognized and unchallenged, they corrupt rational thinking and reasoned debate.

Logical Fallacies

Logical fallacies are so common. If they go unrecognized and unchallenged, they preclude rational thinking and reasoned debate.
Logical fallacies are so common. If they go unrecognized and unchallenged, they preclude rational thinking and reasoned debate. | Source

Sometimes these errors of thinking occur by mistake. Humans are pattern–seeking beings. We tend to see patterns even when there are none.

  • For instance, people looked up into the sky and saw a random array of stars and decided it looked like a dipper.
  • Another example is a misunderstanding of mathematics and science, particularly probability. Coincidences may be far more common than people think.

Other times, charlatans deliberately use tricks to sell lies. Their reasoning seems to make sense, but you could be conned if you cannot see the logical fallacies in their statements.

Here are some of the logical fallacies you are likely to encounter most often. There are so many logical fallacies that I didn't have space for all of them.

The Ad-Hominem Attack

The ad-hominem attack is an personal attack on a person and does not address the claim itself.
The ad-hominem attack is an personal attack on a person and does not address the claim itself. | Source

Ad Hominem (Personal Attack)

This one may be the most common one of all. Someone will attempt to refute a statement by attacking the person who made the statement.

  • Sometimes the attacker will just hurl insults. The person under attack will have his intelligence insulted—he will be called stupid, a moron, a dupe, a fool, etc.
  • Or maybe the attacker will engage in character assassination. The person under attack will be called corrupt, racist, a well-known liar, etc.
  • In political discussions, the word “fascist” is bandied about, and it is most often used inappropriately. The attacker probably doesn’t even know what fascist means-- all he knows that it is an emotionally-loaded term with negative connotations.

Note: It does not matter if the person is being accurately described—perhaps he really is a moron, or a scoundrel, or a fascist. And it does not mean that we should not consider the trustworthiness of the source of a claim. However, it is important to realize that the claim itself is NOT being addressed in ad-hominem attacks. A “bad” person may be making a true claim.

Guilt by Association

“Guilt by association” is another ad-hominem approach. A good example of this was one of the attempts to smear Barack Obama during his 2008 campaign for president. Obama was attacked for having had a prior association with Bill Ayers, a man who was a member of the Weather Underground in the 1970’s, but in 2008 he was a solid citizen and businessman The argument went that since Ayers had once committed a terrorist act and since he had once hosted an event years earlier to promote Obama’s candidacy for the Illinois Senate, Obama must be a terrorist.

Again, guilt-by association is not always wrong. Someone who associates with mob bosses, for instance, may actually be corrupt. However, arguing about associations means that the facts of the claim are being ignored.

Appeal to Authority

The attacker will say that a prominent and/or respected person or group believes a certain claim, so therefore it must be true.

"The Pope said that climate change is endangering mankind, so it must be true."

"The AMA (The American Medical Association) is against the Republican Health Care bill, so it should not be passed."

"Franklin Graham, the well-known religious leader, opposes marriage equality, so it must be wrong."

(For the record, I believe the Pope and the AMA are right, but that does not mean their claims should automatically be accepted. They still need to present facts.)

The reverse side of this attack is dismissing a claim because the person making the claim is not an authority or does not have credentials in the field.

For example, someone might say a man can’t talk about misogyny or abortion because he is not a woman. Or a white person can’t talk about racism because he is not black.

Another example is saying a person is not qualified to speak on a subject because he is not a recognized expert in the field.

  • An actor shouldn’t talk about politics
  • A scientist shouldn’t talk about religion.

The attacker is ignoring the possibility that someone who is prominent in one field could also have a lot of knowledge in another field.

Appeal to Numbers

Often a person will misuse numbers and statistics in an attempt to prove his point.
Often a person will misuse numbers and statistics in an attempt to prove his point. | Source

Appeal to Numbers

Another type of appeal to authority is to claim that since large groups of people believe it, it must be true.

Sorry, “majority rule” is not how we determine facts. Remember, everybody once believed that the earth was flat and that spontaneous generation accounted for maggots.

"The overwhelming majority of climate scientists say climate change is being caused by human actions, so it must be true."

"Christianity is the world’s largest religion, so it must be the one true religion."

For the record, I believe the first statement because it is backed up with evidence; I don’t believe the second statement because there is no evidence that it is true, and there is not even any way to prove it is true.

You’ve heard the phrase, “Figures don’t lie, but liars figure.” Sometimes your opponent will deliberately misuse statistics to confuse you.

Other times, your opponent will dazzle you with charts, numbers, and statistics with the aim of overwhelming you. Usually none of his data is actually relevant to the questions. Sometimes the data is not even correct.

Generalization (Also Called Hasty Generalization or Over-Generalization)

A person will make a claim based on insufficient information, often called “jumping to a conclusion.”

"Today I saw a senior citizen make a turn without signaling. All old people are bad drivers."

"Some black young men are in a gang. All black young men are thugs."

"I bought an apple in this store and it was mushy inside. I won’t shop there again because all their produce is rotten."

Pars Pro Toto

This means “a part taken as the whole”, but I would call it “use the whole to obscure the part” or maybe “see the forest and hide the tree.” It is done to divert attention away from, and even to ridicule, a particular case

“We must save the whales.” “No, we must save all the creatures in the sea.”

“Black lives matter.” “No, all lives matter.”

The second half of each of the above examples is, of course, true, but they do not negate the first half of the statements. They only distract from it.

Slippery Slope

The slippery slope argument takes Action A to an absurd conclusion (Action B), and claims if Action A happens, then Action B will surely follow.
The slippery slope argument takes Action A to an absurd conclusion (Action B), and claims if Action A happens, then Action B will surely follow. | Source

Slippery Slope/Falling Dominos

This is an augment that tries to associate one action with another obviously really bad action. The claim is that the first action will be the start of a slide into other actions. I sometimes call this one “taking things to an absurd conclusion”. The attacker thinks of the absolutely worse outcome, and then says it will inevitably occur as a result of allowing the first action.

In the following three examples, there is no proof that the first action inevitably leads to the second action

"If abortion is made legal, then infanticide will be next."

"If we allow same-sex marriage, next we will have people marrying their dogs."

"If marijuana is legal, people will become heroin addicts."

Post Hoc Ergo Propter Hoc

It’s a Latin phrase for "after this, therefore, because of this." It means if Event B occurs after event A, A must have caused B.

“I prayed my cancer would be cured and now I am cancer free. God answered my prayers.”

The cure happened after the prayer, but that does not mean that prayer cured the cancer. Many other people with cancer also prayed, and some of them died.

Correlation is not causation. Sometimes there are spurious correlations-- two things are associated with each other, but one did not cause the other. A third thing caused both of them.

"Studies show that married people are happier than single people. If you are single and unhappy, you should get married and you will be happy."

"Ever since Mayor X took office, crime has been down in his city. It’s because of his tough law-and-order stance."

In the first example, there is a correlation between happiness and marriage, but perhaps this occurs because happy people are more likely to get married. (Who wants to marry a sour-puss?)

In the second example, perhaps unemployment dropped because a recession ended and this created more jobs for people aand thus there were fewer unemployed people and less crime.

False Choice and Moral Equivalancy

An argument can be framed to make you think there are only two choices or that two very disproportionate things are actually equal.
An argument can be framed to make you think there are only two choices or that two very disproportionate things are actually equal. | Source

False Choice

The problem is stated as if there are only two choices. But often there are many other choices.

“Either we have school voucher programs or we have failing children in public schools. Which do you want?”

The problem of children failing in school does not lend itself to either/or solutions. Perhaps smaller classroom size in public schools is the answer. Perhaps paying teachers more so the best most-experienced teachers will not quit teaching for better paying jobs is the answer. Perhaps an after-school tutoring program is the answer.

Moral Equivalency

This one compares a small thing to a really big thing and declares them equal.

  • President Obama said: “If you like your health insurance, you can keep it.”
  • Donald Trump said: “Obama is the founder of ISIS.”

So are Obama and Trump both liars? False equivalency! Obama said something that he believed to be true when he said it, but it didn’t work out as he predicted it would. Trump told a giant whopper of a lie that had absolutely no basis in fact.

Straw Man

When someone can’t defend his position, he will restate the issue to something he can defend. Then he’ll knock down this “straw man.”

“You are against the death penalty. You want to set murderers loose to kill again.” (Now the argument is no longer about what punishment should be meted out for murder, but whether or not murders should be allowed to run amok in society.)

“You say atheists are as moral as anyone else. Stalin was an atheist and he killed millions of people.” (Now the argument is no longer about secular morality, but about a Russian dictator.)

The Argument from Ignorance

When it is impossible to know the truth of a position, someone will claim that therefore his position must be treated as proven.

“You can’t prove how the universe came into existence, so God did it.”

In some cases, someone will claim that an argument that has even one unproven point means that the whole argument is false.

“You can’t prove how life first arose, so everything that has been proven about evolution is false, and God created the universe in six days just like it says in Genesis.”

Circular Reasoning/Begging the Question

This argument merely restates the premise in different words and then claims the second statement proves the first.

“Donald Trump is the best leader for America because he got elected. Getting elected proves he is the best leader.”

The A Priori Argument

A person starts with a conclusion and then searches for facts to prove it. Facts should always precede a conclusion.

The Appeal to Tradition

A person will say “This is how it has always been done.” Perhaps, but does that mean the usual way is the best way?

False Premise

Sometimes a person will start with a false statement that he takes as a "given." However, the initial premise is not always true, and if it is false, everything else that follows must be called into questions.

"The wealthy are the job creators, so we must cut their taxes and the wealth will trickle down to the middle class and working class."

If the first part of the statement is false (as I believe it is), the rest of the statement has no validity.

When Twisted Logic Fails

A clever opponent will try to win an argument by confusing the issue or by a direct hit to your emotions.
A clever opponent will try to win an argument by confusing the issue or by a direct hit to your emotions. | Source

Six Stratagems for When Even Twisted Logic Fails

Lastly, here are some tricks an opponent might use when he has absolutely no way to defend his positions.

The Non-Sequitur

This is from Latin and it means “does not follow. “ Usually when you ask a politician or his surrogate a question, you don’t get a straight answer. He dances around the topic.

Q. “Do you support the Trump-Ryan health care bill?”

A: “I tell you what I support. I support freedom. Every American should be able to have health care of his choice. Blah blah blah.”

The questioner never gets a direct answer to a simple question.

The Red Herring Defense

Politicians love to use this one. They just pivot to an unrelated topic; they don’t even bother to dance around the original topic.

Q: "Is ending poverty in America important?"

A: "I’ll tell you what is important. Ending terrorism. Blah, blah blah."

Kelly Ann Conway, Trump’s campaign manager and now one of his White House advisers, is the master of this one.

Reductionism

This is the act of taking a complex question and reducing it to very simple terms, sometimes down to a slogan.

Q. "What do we need to do to bring economic gains to everyone?"

A: "We need to make America great again."

The Affective Defense

This one is like a punch to the gut. It is intended to make you feel like you are a terrible person.

“I have every right to my beliefs. You need to respect my beliefs.”

This person is attempting to conflate a reasoned refutation of a position with a personal attack.

The Get-Over-It Defense

If you try to argue about something, you are essentially dismissed and told to stop being a “cry-baby." The reasons you hoped to give for your point of view won’t even be heard.

Q. "Will the election of Donald Trump have dire consequences for the United States.”

A. “Trump won. Democrats lost. Get over it.”

The Song and Dance

Often someone will try to put out so much information that must of it will go unchallenged
Often someone will try to put out so much information that must of it will go unchallenged | Source

One Last Ploy--The Song and Dance

You will frequently see what I call "the song and dance." I see it a lot when politicians and political surrogates are being interviewed on TV.

They will talk very fast, bring up multiple topics, and use every logical fallacy and defense they can manage to throw in. The interviewer is overwhelmed. He can’t respond to everything, and consequently a lot of false information remains unchallenged.

© 2017 Catherine Giordano

I welcome your comments

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    • Duane Townsend profile image

      Duane Townsend 13 days ago from Detroit

      Great Hub Catherine. I wrote a Hub on the same topic a while ago.

      This subject is pertinent in these times.

    • CatherineGiordano profile image
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      Catherine Giordano 13 days ago from Orlando Florida

      Duane Townsend: Thanks for the compliment on my hub. It means a lot coming from someone who is well-versed on the subject of logical fallacies. There are a lot of articles about logical fallacies. I hope I found a unique way to approach the subject. I'll search out your hub on the topic.

    • threekeys profile image

      ThreeKeys 12 days ago from Australia

      Very interesting. Probably if you have lived long enough, you have either been on the receiving end of these ways or put them into practice yourself but never really recognizing that you are doing it. In your estimation what are the better ways to be logical If that makes sense...

    • fpherj48 profile image

      Paula 12 days ago from Beautiful Upstate New York

      Catherine....You write such fabulous, educational hubs~~!! Does this mean you're an "awesome educator??" Well, yes it does, but what else does it mean? In my OPINION, it also means you are a prolific writer and your research is impeccable and by the way, I like you! However, even if I didn't like you, would I enjoy your articles and accept what you present as interesting and accurate? I will if I'm smart.

      If I keep this up and argue with myself, with they finally come and cart me away & lock me up?? LOL..............

      Catherine....In all seriousness, this Hub is a winner!........I thank you for it because I do enjoy debate and it's vital to learn and understand what you have shared here. It's reasonable to believe this bit of knowledge can effectively cut down on the number of times we make fools of ourselves.

      I use the last ploy, the song & dance, a lot when arguing. I mean I literally sing & dance and that ends the argument because people walk away. :)

      And....oh yeah, I just learned that Duane is "well-versed on the subject of logical fallacies."....I think I like him too. I intend to read his hub as well.

      If you're counting my opinion, I think you found an incredibly unique way to approach this subject!! Peace, Paula

    • firstcookbooklady profile image

      Char Milbrett 12 days ago from Minnesota

      A wise man once said to me, "if you cannot dazzle them with your brilliance, baffle them with your B.S." Well, perhaps he wasn't very wise, but, my mom liked him, so he must have been okay... smile.

    • CatherineGiordano profile image
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      Catherine Giordano 12 days ago from Orlando Florida

      threekeys: You are correct--it is so easy to fall into these logical traps and to get sidetracked when they are used against you. The best way not to fall into the traps is to be fact based. Present fact 1. Present fact 2. And then use those facts to reach your conclusion. If you opponent tries to side track you, ask him what fact, in particular, you got wrong and then show proof that you got the facts right. And know when to walk away from the argument. Some people won't fight fair. They will just issue a new volley of ad hominem attacks.

    • CatherineGiordano profile image
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      Catherine Giordano 12 days ago from Orlando Florida

      firstcookbooklady: Perhaps this essay is like a stew. Stir, add a dash of brilliance, and simmer slowly for hours. I hope I have included enough meat. Thanks for your comment.

    • CatherineGiordano profile image
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      Catherine Giordano 12 days ago from Orlando Florida

      fpherj48: Now I'm blushing. Thanks so much for all the praise. I'm retired now, so I have lots of time for research and writing. I'm curious so when I get curious about something I think that maybe other people are curious also. Consequently,I research it and write about it. I sometimes write on subjects that others find controversial, so I see a lot of these logical fallacies in the responses I get to these topics. (Ad hominem attacks seem to be the go-to response.) I like your song and dance suggestion. Usually I just walk away when someone is being unreasonable; next time I'll do a song and dance. I enjoy your sense of humor and I'm glad to have earned your friendship her on HubPages. I get a lot of attacks so effusive praise is a real treat. Thanks.

    • fpherj48 profile image

      Paula 12 days ago from Beautiful Upstate New York

      Catherine, MY FRIEND.....when the creatures attack~"Ad-hominem" is the way to go! Tell them to BUG OFF! It's fair. :)

    • peoplepower73 profile image

      Mike Russo 12 days ago from Placentia California

      Catherine: A very informative article and reference material. I love your graphics. I see these tactics being used everyday by Trump's surrogates on CNN, Trump himself, and especially in the political forums by politicians.

      There are so many tactics , it is difficult to remember them all and recognize when they are being used in an emotionally heated discussion. I think I need to print out your article, reduce it in size and keep it as a pocket reference. The next time someone uses one of these tactics. I could just say, "I'm sorry, you just used a false equivalence."

    • CatherineGiordano profile image
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      Catherine Giordano 12 days ago from Orlando Florida

      peoplepower73: What a great compliment that you want to keep this list with you at all times for reference. I suggest that you copy it, then remove all text except the headlines. Now it is down to manageable size and the headlines will be enough to prompt your memory. Practice when you watch TV news.These tricks are used constantly.

      And thank you for complimenting my little cartoon graphics. Part of the fun of doing these articles is doing the art. I have no talent for drawing at all so I love when I can cut-and-paste pictures to create graphic art. I spend as much time on the art as on the writing. sometimes, I'll spend over an hour just trying to find the exact write picture and then create the graphic so it looks just right. .

    • Robert Levine profile image

      Robert Levine 12 days ago from Brookline, Massachusetts

      Thank you, Catherine. Every citizen of a democracy should be educated on logical fallacies, yet in my own formal education they received only cursory treatment.

      That said, I don't think your example in your introduction of the Big and/or Little Dipper qualifies as a fallacy. It's simply a description--no argument is being made by calling it that.

    • Larry Rankin profile image

      Larry Rankin 12 days ago from Oklahoma

      Interesting read!

    • CatherineGiordano profile image
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      Catherine Giordano 12 days ago from Orlando Florida

      Robert Levine: Thank you for your comment. I totally agree that high school students should be taught rational thinking. I remember my high school teacher, saying "Consider the source." I've forgotten everything else, but that dictum has stood me in good stead all these years.

      As for my mention of the Big Dipper, I had not yet begun to discuss logical fallacies. I was talking about how humans are pattern-seeking in their approach to the world. It was to explain why people are so susceptible to logical fallacies. Perhaps I need to clarify that.

      I appreciate your taking the time to comment and give me feedback.

    • Kathleen Cochran profile image

      Kathleen Cochran 12 days ago from Atlanta, Georgia

      We should all keep this hub posted on our refrigerators as a reminder of what to watch out for as we watch the news, talk shows, commentators, and interviews. Having these tactics defined helps us recognize them when we see them.

      I also think it is interesting who has not responded to this hub. Speaks volumes about the hubbers here who regularly employ these tactics.

    • CatherineGiordano profile image
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      Catherine Giordano 12 days ago from Orlando Florida

      Kathleen Cochran: I would suggest a drinking game--take a shot every time you hear a logical fallacy on the TV news, but you'd probably pass out in an hour. Actually, I wrote this because I am so tired of the ad-hominem attacks and all the other stuff I get all the time in response to my essays. I am actually surprised that I have gotten such a positive response to this hub. The usual trolls are not out. Thanks for the comment.

    • FlourishAnyway profile image

      FlourishAnyway 11 days ago from USA

      This was fabulous and so relevant to any CNN watcher. Your examples were superb. As someone who has a Ph.d. In a very statistics intensive field I can say people often misunderstand and abuse statistics. Hence as the old saying goes, "There are lies, damn lies and statistics."

    • heidithorne profile image

      Heidi Thorne 11 days ago from Chicago Area

      Oh my goodness! How often do we run across these logic fails (or, sadly, use them ourselves)? Sharing on Facebook and Twitter!

    • CatherineGiordano profile image
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      Catherine Giordano 11 days ago from Orlando Florida

      heidithorne: The best compliment I can get is a share. Thank you so much. Writing this has totally change the way I watch the political news on TV. My hope is that if people understand thee tricks, they won't be fooled by them. i

    • profile image

      Hank Cole 11 days ago

      Another very annoying ploy some folks use when they are hit square in the face with truth they don't like is LOUD TALK; as if the only way to win the debate is to out decibel the other.

    • CatherineGiordano profile image
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      Catherine Giordano 10 days ago from Orlando Florida

      You are right. I'd put talking very loud in the song-and-dance category. If you can;'t win 'em, shout 'em down.

    • John With a Blog profile image

      John Patrickson 10 days ago

      This is a great summation. I may use this in the classroom. Thanks for the good work!

    • travel_man1971 profile image

      Ireno Alcala 10 days ago from Bicol, Philippines

      Well discussed, Ma'am! If only all politicians will upgrade their knowledge about "logical reasoning" ,,there'll be no heated discussion about petty things. :)

    • CatherineGiordano profile image
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      Catherine Giordano 9 days ago from Orlando Florida

      John with a Blog: Thank you. I am honored that you want to use this in your classroom. Rational thinking should be a required course in high school.

    • CatherineGiordano profile image
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      Catherine Giordano 9 days ago from Orlando Florida

      travel_man 1971; And if wishes were horse... Seriously, I'm with you on this. Politic is the main arena for logical fallacies and government is the worse for it,

    • MsDora profile image

      Dora Isaac Weithers 7 days ago from The Caribbean

      This article is so insightful and is a good reference for speakers (including me) who might need to brush up their reasoning skills. Thank you.

    • CatherineGiordano profile image
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      Catherine Giordano 7 days ago from Orlando Florida

      Thanks MsDora. It is good to check your speeches for logical fallacies, just to avoid having your opponents do it for you. Also, if you spot a logical fallacy, it does not necessarily mean the statement is wrong, it jut means it should be examined carefully, and if it is in your own work, buttressed with facts.

    • John Welford profile image

      John Welford 43 hours ago from Barlestone, Leicestershire

      You have actually broadened the scope of this Hub beyond what can strictly be termed logical fallacies, but that's absolutely fine in this context. It amazes me how quickly politicians fall into these traps when they find themselves defending the indefensible - and the same goes for religious fundamentalists.

    • CatherineGiordano profile image
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      Catherine Giordano 39 hours ago from Orlando Florida

      John Welford: I did go beyond logic fails, but I put the extras in a separate section because they too are attempts to corrupt reasoned debate..They are often lumped together. I wanted to keep things having to do strictly with reasoning issues separate from other things that are not fallacies, but also cloud rational reasoning.

    • profile image

      Paul Braterman 34 hours ago

      The whole business of identifying kinds of fallacy is trickier than it looks; check out the #Fallacyfork arguent of Maarten Boudry and Massimo Pigliucci, two heavyweight rationalist philosophers

    • CatherineGiordano profile image
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      Catherine Giordano 12 hours ago from Orlando Florida

      Paul Braterman: I have heard of the fallacy-fallacy. This when you start to see fallacies everywhere and thus they impede reasoning. Everything in moderation. It is why I warned in my essay that finding some of thee fallacies in an argument do not prove or disprove the statement. They are just a warning sign that the person using these fallacies may actually have no basis in fact for his argument.

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