Critical Thinking: Common Informal Fallacies, Part 2

thinkingcapwhoaThanks for continuing in this discussion of critical thinking and the most common informal fallacies. Recall that informal fallacies occur when we are making arguments using inductive reasoning where the conclusion does not necessarily follow from the premises because some new information is implied. This is often the kind of argument we need to make in real life, both with others or even inside our own self.  What we hope for are conclusions that are strong and likely to be true and we can do this by avoiding informal fallacies where we don’t deal with the facts properly. In the first post on this subject, I explained fallacies of presumption where the facts are misused. Here I will discuss two other categories of informal fallacy: fallacies of relevance, where at least one of the premises is unrelated to the conclusion, and fallacies of ambiguity where the language is too obscure.

*Recall that none of the examples or cartoons here necessarily represent my own opinion. This is a caveat I shouldn’t have to make after this next section!*

Fallacies of Relevance: A Premise is Unrelated to the Conclusion

Here I will illustrate four different ways we can come to irrelevant conclusions by basing our argument on unrelated statements or facts.

Ad Hominem (just attack the advocate’s general character, not their argument)

The words “Ad Hominem” are Latin words meaning roughly “from human,” and all of the fallacies like this result from attacking/praising the character of the person who promotes the idea instead of
evaluating the idea itself.

I love this cartoon for the simplicity!

I love this cartoon for the simplicity!

If reasoning against an argument seems too hard, then just attack the person! This happens all the time  and comes in many flavors. You might actually attack the source of an argument which could be more than a single person, such as an organization, a nation, or a religion, and this would be the “genetic” flavor of ad hominem; it might be enlightening to study the history of how an idea gained acceptance, but it’s nevertheless irrelevant to its validity. The “abusive” ad hominem occurs when one tries to lower our regard for someone and therefore anything they would say, by hurtling insults at them, accusing them of moral transgressions or by some other means making them look ridiculous. The “circumstantial” flavor is close to this, only in this instance we are sowing seeds of doubt by questioning a person’s motives; yes, a person’s circumstances might give them a vested interest in the outcome of a situation, but does that mean one can never think or act unselfishly? I’d hate to think so! “Tu quoque” (in Latin, something like “look who’s talking”) is an ad hominem flavor whereby one attacks a position by accusing the advocate of hypocrisy. But you do it too! She doesn’t practice what she preaches! We all know that two wrongs don’t make a right. And also, just because I’m throwing out a bunch of cliches here doesn’t mean that avoiding cliches isn’t good writing policy. Finally, let’s not forget the “halo” effect flavor. In this type of ad hominem an idea is considered reliable or sacred simply because of the source. My Mother loves Oprah Winfrey and so do I. But to hear my Mother tell it, the woman can do no wrong. I’m quite sure Oprah herself would object to this. Last, but not least, there is something called “Poisoning the Well”. In this flavor of ad hominem one attacks a person’s credibility. If they have lied in the past then they could be lying in the present. As with all the others, however, this is irrelevant. We judge the present idea on its own merits.

Example of a genetic ad hominem: No boy scout would ever lie because “to be honest” is part of the boy scout oath and an important tradition of scouting since their inception.

Example of abusive ad hominem: Why would anyone listen to what this man has to say about gun control or global warming or anything else? He spent three years in federal prison for tax fraud. Isn’t that enough?

Example of circumstantial ad hominem: Of course Senator Levin supports the auto bailout. He represents Michigan, home of the “Motor City”

Here we have the Tu Queque ad hominem, with a bit of the genetic flavor thrown in.

Here we have the Tu Queque ad hominem, with a bit of the genetic flavor thrown in.

Example of  Tu Queque ad hominem: Who is she to be against abortion? She had one herself when she was twenty.

Example of Poisoning the Well: This woman lied about her employment history on her resume. She lied about the number of children she had at the welfare office. Why should we believe who she says was driving that night?

Appeal to Authority

With this type of informal fallacy, one  justifies their idea by appealing to some source with a claim to expertise or inside knowledge. If anyone has read my welcome page, they would know that this kind of fallacy is particularly odious to me. My personal motto is “Nullius in Verba” which basically means’ “by no one else’s word.” A part of this illogical ploy is an attempt to get you to doubt your own judgement or feel inadequate to understanding the intricacies of the issue. Either because of a lack of self esteem  or intellectual laziness, people are too often willing to to just believe or do what the big guy(s) says. The reason this is a logical fallacy of course, is that even an expert can be wrong in a particular thing. The authority might be anyone from a single individual to some type of organization to simply cultural tradition. I happen to have a fair degree of expertise on the issue of climate, but when I try to press my opinion on climate change I make sure to never offend the intellect of  the person I’m talking to by saying “because I said so!” If the point happens to be too complex for the time allowed I don’t expect them to agree with me until after I’ve given convincing evidence which they can think through for them self. I am continually appalled by the number of people who just go to their doctor and do whatever they are told. Apparently they are unaware of the huge diversity of opinion that exists on almost any topic in the medical community. Not only is your doctor fallible (because she is human), but why assume her values align with your’s, not to mention that she is not the one to have to live in your body once she walks away. No one can advocate for yourself like you.

Example of an Appeal to an Authority of One: For a millennium and a half, Aristotle was deemed to be the greatest authority for all natural knowledge. But as great a philosopher as I personally agree that he was, he made one giant mistake that held back progress for centuries:  that experimentation is flawed because any artificial intervention in nature will alter the natural result. This looks like a small error, but it was not. It had a large effect on the history of scientific and technological progress. So many intuitive ideas we may have about the world are shown to be wrong (for example, for something to keep moving we need to keep pushing it, correct?) when we actually do an experiment and make measurements. It wasn’t until Galileo stepped up, questioned the great Aristotle, and tested Aristotelian truth that science began to lift itself out of the scientific darkness.

Example of an Appeal to a Group Authority:  For centuries people have allowed the Catholic Church to speak for their own conscience in the face of their God. This concession of personal intellectual autonomy grew until the Church controlled all aspects of life. One could even pay the Church to have sins removed (!); who was actually God? It’s probably no coincidence that the Reformation occurred synchronously with the publication of the first  mass produced typeface Bibles so that people could read “the word of God” for them self.

Example of an Appeal to Traditional Authority: It is generally assumed that the best

How often do we just let the authority of tradition dictate our beliefs without questioning them?

How often do we just let the authority of tradition dictate our beliefs without questioning them?

environment to nurture a committed relationship is within the institution of marriage. This is true to the point that married people are bestowed special rights and privileges. Some people are aghast that this venerable institution is “threatened” by including homosexuals who were traditionally excluded. But is marriage really the best way to nourish a relationship? Why is the divorce rate so high? Why do so many people think more about the flower arrangements at a Wedding ceremony rather than the vows exchanged? My point here is that it is not logical to just assume a previously accepted tradition is the one that will be right for you.

Fallacies of Ambiguity: Unsound Conclusions Result from Misuse of Language

In the case of Fallacies of Ambiguity we arrive at sketchy conclusions because we have not maintained clarity and consistency in our language. This seems like an error that would be easily discerned. However, the shift in meaning or the twist of grammar can often be subtle making it difficult to find the problem – especially when we have to think fast. The best way to avoid this lack of clarity is to make a habit of always being aware of how you arecwln3219l.jpg using language yourself. Do you ever change the definition of a word mid-argument? Are you careful to define your terms before an argument begins? Our
reasoning often becomes confused because we do not even start on the same page. There are many types of Fallacies of Ambiguity. Here I will discuss four: Equivocation, Amphiboly, Hypostatization, and Division/Composition.


With equivocation, a single word or short phrase has two different meanings, and this meaning shifts at least once in the course of the argument. A person may actually use this device to accuse you of inconsistency, when in all actuality, they are the one who sre being inconsistent with the way they define their word(s).

Example of Equivocation: “You say you believe in the miracles of science, so why do you reject the miraclesblackboard_equivocation%5B1%5D of the Bible?” If you are not clear about how the words are defined, you may feel like you’ve been tricked. The “miracles” of science refer to the astonishing achievements that scientists have made toward understanding the natural world. The “miracles” of the Bible refer to something else entirely – to the events which defy those very laws scientists seek to understand. Since it is the word “miracle” which connects both premises to the conclusion, if you change the meaning of this connector, the conclusion fails entirely.


Amphiboly occurs when poor grammatical structure causes the meaning of a sentence or short paragraph to become ambiguous. This can end up being very humorous, and lots of late night talk shows use these errors from newspaper headlines or classified ads for comedy segments. A few examples of these grammatical errors might be:

dangling modifier example: (Dangling modifiers are phrases describing the subject, except that the subject is missing. This is probably because the writer thinks the subject is too obvious and doesn’t need to be made explicit.  But is easy to just grab on to the next best noun. This can make the sentence nonsensical.) “Walking around the zoo, the monkeys were screeching madly.” No, the monkeys were not walking about the zoo; that would be the children. It should read: “Walking around the zoo, the children saw the monkeys screeching madly.”cgr0556l.jpg

ambiguous antecedent example: (Ambiguous antecedents are when pronouns don’t match up to the nouns they are supposed to replace.) “If your DOG does a POO, please place it in the trash bin.” Does “it” refer to the dog (poor puppy!) or the poo?

not using enough words: “Just in. Spring Blouses for Women with 12 – 14 necks.” “Dead Wife Says Husband Kept a Loaded Gun” “Puppies for sale. Come quick before they disappear!”

While these examples were funny, amphiboly can be used for more devious purposes. This is why when we are testifying in a court of law we swear to tell not just “the truth” but also “the whole truth” (you can’t leave important facts out) and “nothing but the truth” (no part of your testimony can be a lie).

Hypostatization (or Reification)

This fancy sounding fallacy is actually a fairly simple concept. Hypostatization is when we treat an abstract concept as if it is a real thing. This is often a case of anthropomorphizing an inanimate object (“Love will find a way,” “Nature abhors a vacuum,”Let the market decide.”). In some cases hypostatization can be helpful in understanding a concept or expressing a poetic idea. Speaking of the free market as having an “invisible hand” is a colorful metaphor that helps to understand how supply and demand seem to balance out when prices are allowed to change. We don’t actually think the market has a hand. But in other cases hypostatization can be malevolent, as when someone declares that “nature” deems some races to be superior and then goes on to justify slavery or extermination. The racist uses “nature” to divert attention from their own hateful self.

Now that I’m finished discussing fallacies, what fallacy does the following cartoon describe?jmp060307l.jpg

None that I can tell. I just think it is hilarious!

Do you have a “favorite” fallacy I left out? Please tell.

Posted on February 14, 2013, in Uncategorized and tagged , , , , , , , , . Bookmark the permalink. 5 Comments.

  1. interesting. I have one question. What if the well is so self poisoned it would be unjust to allow oneself to be drowned in the contamination? I once read a person has no obligation to believe another who has proven through time to be not believable. Critical thinking would be tossed out the window by allowing the person to continue spreading even more poison. ( hope I am not being too ambiguous) 🙂

    • Crys, If a person has continuously lied in the past, it is logical to presume they would continue the same behavior in the future. It would be most sane to distrust them. “Poisoning the Well” is a bit different. It does not refer to the well being poisoned in your own mind. It refers to you tainting another person’s mind with regard to your disliked person over an unrelated matter. In the example I gave above I was imagining a lawyer speaking to a jury regarding an automobile accident. He was poisoning the jury. Maybe he was bringing up the only other lies she has told in her life.

  2. just for the readers…. I’m sure you meant either; it is logical they would continue the same behavior OR it is not logical to believe they wouldn’t continue..etc…. ?

  3. Lori, I used a double negative and that can be hard to interpret. Did I correct it or did I miss your point? Thank you for reading!

  1. Pingback: Put On Your Thinking Cap | Rethinking Being Social

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