Common Logical Fallacies in Argument Papers

(from Grammar Girl: Quick & Dirty Tricks)

5 Types of Fallacies You Don’t Realize You’re Using in Your Writing

 (By Lora Wegman, read by Mignon Fogarty)

The key to writing a strong argument is logic. Even writers who typically have sound logic, however, can fall into illogical conclusions when they are passionate about a topic and use unsound arguments—typically referred to as fallacies.

Here are a few tips for identifying the most common fallacies in writing and how to avoid them.


This fallacy, also called a “hasty generalization,” happens when the writer draws a conclusion about a group of people based on insufficient data. Often, these assumptions come from stereotypes and implicit biases, so these can sometimes be the trickiest fallacies to detect in your own writing. Perhaps you assume, for instance, that all members of a particular political party have the same stance on the death penalty, or you believe that all people who attend a certain school are wealthy. Basing an argument on unproven assumptions will ultimately make your position weaker and therefore easier to attack. As you’re reviewing your writing and come across an assumption, be sure to ask yourself, “Do I really know that this is true?”

Straw Man

A straw man argument oversimplifies an opponent’s position and then attacks it. This is often a big one for politicians, who might portray larger-picture views instead of nuance. For example, imagine that you are assigned to write an essay opposing school uniforms. If you state, “Requiring students to wear uniforms means they will lose all sense of individuality,” then you may be setting up a straw man argument. Instead of arguing for why students should be able to wear their own outfits, you instead take the argument to a simpler and perhaps more emotional conclusion, and then argue against that broader implication. When you’re listening to politicians, as yourself whether their argument is against what their opponents are actually suggesting, or have they thrown a straw man into the ring by misrepresenting their opponents’ position as something more extreme?

Ad Hominem

In ad hominem attacks, a position is attacked not through reasoning related to the argument itself, but instead by attacking the opponent’s personal character. For example, if Squiggly says we should have chocolate cake for dinner, and Aardvark responds by saying that  Squiggly is an idiot, he’s using an ad hominem attack—addressing only Squiggly’s character—and not making a logical argument about why chocolate cake for dinner is bad.

Closely related to the ad hominem attack is the tu quoque fallacy: This is when, instead of opposing an argument or a criticism, the speaker or writer responds by turning it back on the accuser. It’s essentially an argument that says, “Oh, yeah? What about you?” An example would be crafting an argument against doctors’ anti-smoking messages by pointing out statistics about how many doctors smoke. Those facts would have nothing to do with the anti-smoking argument itself but instead simply attack the behavior of those on the opposing side.

Post Hoc

A post hoc argument assumes one event caused another, based solely on the order of occurrence. The full Latin phrase—“post hoc, ergo propter hoc”—means “after this, therefore, because of this.” So, to use a historical example that was once believed to be fact: “People who spend time outside at night are more likely to catch malaria, therefore, night air causes malaria.” The fact that things happen in order doesn’t mean that one thing actually caused the next to happen. We now know that malaria is caused by a parasite transmitted by mosquitos, not by night air.

This is somewhat like the “slippery slope” fallacy. In these cases, you’re arguing against something with the assumption that it will lead to another undesirable outcome through a series of incremental steps. But in reality, the events may not actually be related if they do occur, or the first event might happen without the catastrophic result.

Red Herring

A red herring is a classic misdirection. We see this all the time in fiction, from Sherlock Holmes stories to modern-day thrillers. False clues are planted to throw the reader off. Similarly, a red herring fallacy can pop up in your writing when your argument veers into an area only tangentially related to the core topic. This may be purposeful, but it’s also easy to do without intending to. Here’s an example in which President Ronald Reagan used humor and diversion as a red herring in answering a debate question:

 Reporter: You already are the oldest president in history. … President Kennedy had to go for days on end with very little sleep during the Cuban missile crisis. Is there any doubt in your mind that you would be able to function in such circumstances?

Reagan: Not at all … and I want you to know that also I will not make age an issue of this campaign. I am not going to exploit, for political purposes, my opponent’s youth and inexperience.

So, how do you catch yourself using fallacies? Play devil’s advocate with your own writing. Ask yourself what the logical counter-argument is and whether yours holds up. Then, identify any stereotypes or biases you are inadvertently using to inform your position. This should help you identify holes in your logic and set you up for a stronger result.