Logical Fallacies
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Estimated time to complete: 25-35 minutes (including quiz) Supported Objective: CO1: Develop three clearly-written, well-researched, persuasive papers which demonstrate both critical reading and critical thinking skills. |
In an argumentative paper, you make claims and support them with evidence, but the evidence alone is not enough. You must explain the relationship between the evidence and the conclusion you draw from it (remember ICE?), and in doing so, you need to be logical. Below are a few logical errors that are common in ESL118 papers.
Scare Tactics (aka Vice and Virtue Words, Loaded Words, Subjective Language):
Some words contain strong positive or negative connotations. As soon as you use them, you are reducing a complicated issue to a simple threat or exaggerating the danger (or benefit) well beyond its actual likelihood.
Because of the possibility of a terrorist hijacking or a mechanical failure, flying on a plane is too dangerous and should be avoided altogether.
It is widely accepted by reasonable people that free-trade has a positive effect on living standards, although some people ignorantly disagree with this.
Either/Or Choices (aka Oversimplification, Black and White Arguments):
Instead of acknowledging that a complicated question can be effectively answered in multiple different ways, the writer allows only two, diametrically opposed, possible answers.
Either you support the President in everything he says, or you are not a patriotic American.
Americans must either change their eating habits or they will die of diabetes and heart disease.
Bandwagon (aka Ad Populum):
Bandwagon appeals suggest that simply because a lot of other people are doing something, everyone should be doing it. The fact that many people believe something to be true does not make it true.
Most Americans believe that if their children participate in high school sports they will be more successful in life.
Everyone is buying the newest iPhone, so it’s a good idea for you to get one too.
Slippery Slope:
This means to greatly exaggerate the supposedly inevitable future consequences of an action by suggesting that one small step will initiate a process that will inevitably lead the way to a much bigger result.
If college students start drinking Soylent instead of eating regular meals, they will have no reason to spend time socializing with their friends and families and will become isolated and depressed and eventually commit suicide.
If we don’t all start consuming Soylent soon, agriculture, and especially the raising of animals for meat, will release so much greenhouse gas of various kinds into the atmosphere that we won’t be able to stop climate change. The coastal areas will flood, society will crumble and we will be plunged into chaos.
Faulty Causality (aka post hoc ergo propter hoc, confusing correlation and cause):
Sometimes writers confuse chronology with causality, and think that because one event happened before another, the first event caused the second event, or because two events co- occur that one must cause the other.
Many children have a genetic predisposition to become obese, so if they become obese, it’s not their parents’ fault.
Rob Rhinehart started drinking Soylent, and within a couple of weeks his skin had cleared up, his teeth were whiter, he was adding miles to his daily runs, and even his hair was healthier; therefore Soylent improved his health.
Overgeneralization (aka Sweeping Generalizations, Hasty Generalizations):
The writer makes a claim or judgement based on limited evidence. This happens often when writers use a single anecdote and try to generalize from it. Words such as all, always, and never, may come into play, but cannot be supported.
My father smoked four packs of cigarettes a day from the age of fourteen and lived to be seventy-nine. Therefore, smoking really cannot be that bad for you.
Fast food is fattening, so if you eat fast food, you are bound to become obese.
Cherry-Picking:
This is using only the evidence that supports the point of view that the writer holds and ignoring evidence that doesn’t. Statistics, in particular, are easily manipulated to give a biased view.
80% of the doctors surveyed in this study think the new procedure is too dangerous to use on children (while at the same time the writer ignored two other surveys of doctors who think the new procedure is probably perfectly safe).
Ignoring the Elephant in the Room:
An idea (often a counterargument) is so obvious and important that everyone who reads or thinks about the topic acknowledges that it cannot possibly be ignored, and yet it is not mentioned.
The main causes of obesity in the U.S. are watching TV, playing video games and the overuse of computers.
Here is a poster of more logical fallacies: SchoolOfThought_FallaciesPoster.pdf Download SchoolOfThought_FallaciesPoster.pdf
Fundamentals for Logical Analysis
- Always remember never to say always and never (and all, none, everyone, nobody). These lead to generalizations.
- Even if you are sure that one thing is the cause of another, it may not be the only cause. Consider other angles, and be careful not to oversimplify.
- Suspicious words like "undoubtedly" and "obviously" are often followed by hasty generalizations and oversimplifications.
- Any opinion you have must be qualified, hedged, and specified; and must be supported completely by facts, examples, or (when allowed) direct personal experience.
Take this low-stakes quiz and see whether you can identify the logical fallacy in each case: Logical Fallacies