Reasoning: Other FallaciesWriter's Web
By David Roberts
(printable version here)

There are a number of other common errors that writers make when crafting their arguments. These are more difficult to categorize than the previous section details, but they are nonetheless very important to remember when writing argumentatively.

False Dilemma

Writers construct false dilemmas when they argue that there are only two options to address an issue, and since one is undesirable or impossible, we must choose the other. This is fallacious for two reasons. First, there could be more than two options. It would sound ridiculous for someone to say,

“We can either burn the house down and collect the insurance money or we can continue living in an unsafe house. Since we shouldn’t keep living in an unsafe house, we should burn it down.”

In fact, other options exist: selling or repairing the house, for instance.

Constructing false dilemmas is also fallacious because the two options the writer constructs may not be mutually exclusive; that is, one may be able to do both of them. Consider this argument:

“We can either go to the river or eat sandwiches. We’re both hungry, so we should eat sandwiches and not go to the river.”

This is a false dilemma because one could likely eat sandwiches and go to the river, or even eat sandwiches at the river. In your own writing, it thus becomes necessary to check to see that you are not overlooking alternatives to choices you have listed and that the choices you have listed really are choices and not simply options, of which more than one can be selected at once.


The strawman fallacy takes its name from – what else – a strawman guarding a field from crows. This fallacy occurs when writers mischaracterize opponents' positions in order to more easily refute it. Writers might make opponents' positions more extreme or sound contradictory to accomplish this. This is problematic because it does not truly address the issue at hand.

It is sometimes difficult to avoid the strawman fallacy. After all, since one is disagreeing with the objection in question, it can be difficult to give due credit to an opposing point of view. It is essential to do this, however, for it will bolster the strength of one's argument. In order to avoid this fallacy, one should be careful to:

1. Ensure that one understands the objection in question; and
2. Take deliberate care in articulating that position and its flaws to the paper’s audience.

Interestingly enough, an argument that makes concessions to opponents or at least carefully examines them is often more persuasive because it appears more reasonable to the audience.

Appealing to Authority

As the name suggests, appealing to authority occurs when writers argue that a position should be accepted because some sort of authority believes it should be accepted. There are several difficulties with this argument, however. Kahane and Cavender (1998) cite two problems. First, some authorities are more credible than others. Personal biases as well as limited professional experience can undermine a source’s credibility. Second, authorities in one field are not always authorities in others. George Clooney is less credible than a real cardiologist to speak about the procedures for open heart surgery.

It is also sometimes difficult to determine whether – and how – to appeal to authorities. After all, academic writing poses something of a paradox: writers at once are supposed to support their claims with evidence – presumably offered by authorities – while simultaneously becoming independent voices themselves. In order to properly use authorities, writers will do well to focus on evaluating authorities. A few questions may be helpful in this regard:

  • How does the authority come to this conclusion?
  • What makes an authority credible?
  • Why might a person’s status as an authority on the issue give extra credence to accepting that authority’s conclusion?

Fallacy of the Beard

This faulty reasoning strategy takes its name from a man with a beard. One could conceivably prove that no one has a beard (or, on the other hand, that everyone has a beard) using this reasoning strategy. The argument goes like this:

Person A: Does a person with one whisker have a beard?
Person B: No.
Person A: Well, what about a person with two whiskers?
Person B: Nope.
Person A: Three, four, five?
Person B: No, no, no!
Person A: Therefore, no one has a beard!

This reasoning is obviously faulty, though: one sees people with beards all the time. This faulty reasoning results from the questionable premise that because two things are not different because their exact numerical difference from one another is not known. Even though a precise number of whiskers does not separate a beard from a non-beard, there is still a difference between the extremes of clean-shaven and having a full beard.

Writers must use caution when discussing vague concepts such as how tall a person must be in order to be tall and similar issues. These issues could conceivably come up when discussing the legal age to drink or other public policy questions. It is important, however, not to confuse small differences at the margins with the large differences between the polar ends of an issue.

Slippery Slope

This fallacy usually involves a writer who takes the audience through a long string of consequences, often concluding with a very dire consequence, and uses it to argue that some other, comparatively minute action should be taken. One might claim the following:

“If we eat meat, then we disrespect animals. If we disrespect animals, we will disrespect all forms of life. But if we disrespect all forms of life, we will begin killing other humans. Eventually, we will kill everyone. Therefore, no one should ever eat meat.”

Usually, one of these causal relationships is overstated; there are insufficient grounds to accept that doing the first action will result in the dire consequences the argument predicts.

When writing, one will likely employ several linked consequences together. This by itself is legitimate, but one must take care to check that the linkages are indeed legitimate. When writing in this way, it may be helpful to ask oneself whether doing the first action really causes the last to occur.

Begging the Question

This fallacy, also known as circular reasoning, occurs when writers simply restate what they seek to prove as their conclusion. For example, one might say,

“This test is hard because it is so difficult!”

The reason offered, that it is very difficult, would certainly make the test hard, but this statement is circular because it does not address why the test is hard. In the editing process, writers will likely benefit from persistently asking themselves, “But why is this true?” If one looks for support for this answer and merely find a restatement of it, then the reasoning is circular. At this point, it becomes necessary to either support the point or to make the point less sweeping and then support it.


Equivocation occurs when a single word or phrase is used differently in at least two parts of an argument. Consider the following:

“If one does not weigh much, then one is light. Mark doesn’t weigh very much. Therefore, Mark is light. Thus, Mark cannot have dark skin.”

The equivocation occurs in the last statement: before this, “light” referred to Mark’s weight, not skin color. This reasoning is fallacious because Mark may indeed have dark skin and not weigh very much. While this example is rather obvious, it can sometimes be difficult to detect these shifts in word meanings, especially over a prolonged argument in a complicated subject. When using buzzwords or words which have multiple meanings, be sure that to examine them to ensure that you are using it in the same context each time. One method of doing this is to insert the definition of the word every time you use it in your argument.

Questionable Analogy

One primary form of argument writers rely upon is argument by analogy. If one thing is comparable to another, a similar action may be appropriate for both. However, not all analogies are appropriate. Specifically, the relevant characteristics may not be the subject of comparison, but rather a minute trait with little relevance on the appropriate action. For example,

“The speed of light can be reached! We didn’t think that anyone could run a four-minute mile or that the sound barrier could be broken, but we eventually did both. It stands to reason that the light barrier, which some people don’t think can be broken, will eventually be reached.”

Are running a four-minute mile, or reaching the speed of sound, really good analogies for traveling at 186,000 miles per second? The fallacy, of course, is that one may have credible reasons why the speed of light will not be reached. That some people did not think it was possible to run a four-minute mile or exceed the speed of sound are not sufficient grounds to conclude that reaching the speed of light will occur.

When writing, it thus becomes important to make sure analogies are – well, analogous. In other words, try to ensure that you are comparing the relevant parts of two different situations.

Ad hominem

Another Latin name, this fallacy translates, “To the person.” In other words, to make an ad hominem argument is to attack a person rather than the person’s argument. The following is an example of this:

“Sally says I should drive a more fuel efficient car, but her car gets even less mileage than mine; therefore, there is no reason for me to drive a more fuel efficient car.”

The conclusion the argument makes is simply too strong: it is not entirely clear that Sally is being hypocritical (she may not be able to afford a more fuel efficient car, for example); and even if she is hypocritical, it is not clear why her hypocrisy makes it bad for the author of the argument to drive a more fuel efficient car.

Writers should bear in mind two specific pieces of advice when critiquing others and their arguments.

1. Personal background is not always irrelevant. It may indeed be questionable to accept someone’s view that lying is always wrong if that person consistently lies and defends his or her dishonesty.
2. Remember the argument and not just the person making it. Often, it is more appropriate to address a person’s arguments and not the person’s personal behavior. In these cases, one should be sure to attack a person’s argument rather than the person.

Works Cited: Kahane, Howard and Cavender, Nancy. 1998. Logic and Contemporary Rhetoric. 8th edition. Belmont, CA: Wadsworth.

Back to 'Analysis and Argument'
Writer's Web
| Writing Center | Make an Appointment | Library

Copyright Info