Fallacies

Introduction

Fallacies are errors or tricks of reasoning. A fallacy is an error of reasoning if it occurs accidentally; it is a trick of reasoning if a speaker or writer uses it to deceive or manipulate his audience. Fallacies can be either formal or informal.

Whether a fallacy is an error or a trick, whether it is formal or informal, its use undercuts the validity and soundness of any argument. At the same time, fallacious reasoning can damage the credibility of the speaker or writer and improperly manipulate the emotions of the audience or reader. This is a consideration you must keep in mind as a writer who is trying to maintain credibility (ethos) with the reader. Moreover, being able to recognize logical fallacies in the speech and writing of others can greatly benefit you as both a college student and a participant in civic life. Not only does this awareness increase your ability to think and read critically—and thus not be manipulated or fooled—but it also provides you with a strong basis for counter arguments.

Even more important, using faulty reasoning is unethical and irresponsible. Using logical fallacies can be incredibly tempting. The unfortunate fact is they work. Every day—particularly in politics and advertising—we can see how using faults and tricks of logic effectively persuade people to support certain individuals, groups, and ideas and, conversely, turn them away from others. Furthermore, logical fallacies are easy to use. Instead of doing the often difficult work of carefully supporting an argument with facts, logic, and researched evidence, writers routinely to the easy path of tricky reasoning. To be effective with college-level writing, you must recognize and avoid the logical fallacies.

Formal vs Informal Fallacies

Most formal fallacies are errors of logic: The conclusion does not really “follow from” (is not supported by) the premises. Either the premises are untrue, or the argument is invalid. Below is an example of an invalid deductive argument:

Premise: All black bears are omnivores.

Premise: All raccoons are omnivores.

Conclusion: All raccoons are black bears.

Bears are a subset of omnivores. Raccoons also are a subset of omnivores. But these two subsets do not overlap, and that fact makes the conclusion illogical. The argument is invalid—that is, the relationship between the two premises does not support the conclusion.

“Raccoons are black bears” is instantaneously recognizable as fallacious and may seem too silly to be worth bothering about. However, that and other forms of poor logic play out on a daily basis, and they have real world consequences. Below is an example of a common fallacious argument:

What Are Informal Fallacies?

Informal fallacies take many forms and are widespread in everyday discourse. Very often they involve bringing irrelevant information into an argument, or they are based on assumptions that, when examined, prove to be incorrect. Formal fallacies are created when the relationship between premises and conclusion does not hold up or when premises are unsound; informal fallacies are more dependent on misuse of language and of evidence.

It is easy to find lists of informal fallacies, but that does not mean that it is always easy to spot them.

How Can You Check for Logical Fallacies?

One way to go about evaluating an argument for fallacies is to return to the concept of the three fundamental appeals: ethos, logos, and pathos.

• Ethos is an appeal to ethics, authority, and/or credibility.
• Logos is an appeal to logic.
• Pathos is an appeal to emotion.

Classifying fallacies as fallacies of ethos, logos, or pathos will help you to understand their nature and to recognize them. Please keep in mind, however, that some fallacies may fit into multiple categories.

Fallacies of ethos relate to credibility. These fallacies may unfairly build up the credibility of the author (or his allies) or unfairly attack the credibility of the author’s opponent (or her allies). Some fallacies give an unfair advantage to the claims of the speaker or writer or an unfair disadvantage to his opponent’s claims. These are fallacies of logos. Fallacies of pathos rely excessively upon emotional appeals, attaching positive associations to the author’s argument and negative ones to his opponent’s position.

Summary

Key terms include:

• Formal fallacy – errors of logic
• Informal fallacy – irrelevant information
• Logical Fallacy – errors in reasoning

“Chapter 3 – Argument.” By Kirsten DeVries. Retrieved from: https://vwcceng111.pressbooks.com/chapter/chapter-3-argument/#arepositoryoflogical Licensed under: CC-BY-NC-SA

“Defining and Identifying Logical Fallacies.” By Lumen Learning. Retrieved from: https://courses.lumenlearning.com/olemiss-writing100/chapter/common-logical-fallacies/ Licensed under: CC BY-SA

“Logical Fallacies.” By Excelsior OWL. Retrieved from: https://owl.excelsior.edu/argument-and-critical-thinking/logical-fallacies/ Licensed under: CC-BY