Argumentation: Understanding and Classifying Logical Fallacies

Lesson Plan - Get It!

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When supporting a point in writing, it is important to build rational, reason-based arguments that cannot be easily dismissed or disproven due to errors in logic.

When an argument is invalid due to a flaw in the logical reasoning of the argument, that is called a logical fallacy.

When a writer commits a logical fallacy, the entire argument becomes invalid, regardless of the merit of the premise or inclusion of sound evidence. This is why writers should avoid logical fallacies in their writing at all times.

There are several common logical fallacies. Read about each one below:

Ad Hominem

Using an insult instead of offering solid support of the argument or point.

Strawman

Making up a non-starter argument or position defense based on a cheap, weak argument that the opposing viewpoint doesn't actually present or defend.

Think of it as a type of boogeyman: it isn't real, it's a false threat, and it holds no actual meaning.

Appeal to Ignorance

Using ignorance (lack of knowledge) as an argument in favor of or against something.

This doesn't (and can't) actually support a point because it only demonstrates a lack of knowledge or understanding on the part of the speaker or writer.

False Dichotomy

Creating a binary opposition of two points as if they are the only available considerations, or pairing two ideas as diametrically opposed when they actually are not.

Slippery Slope

Presenting increasingly risky, dangerous, or unlikely outcomes or scenarios as a result of an idea in lieu of an actual argument with supporting evidence and claims.

Think of this as skipping the argument altogether and rushing toward a worst-case scenario for which there is no basis.

Circular Reasoning

When an argument is used as both a point and its own support, it cannot come to any new conclusions. It is based on an erroneous assumption from the jump and continues to spin around in circles on that basis.

Hasty Generalization

Using assumptions, overstatements, or stereotypes as a means to skip ahead to reader agreement without building a well-supported argument.

Supporting points must be specific, verifiable, and directly related to the point. Some hasty generalizations include "all the time," "never," and "girls all like wearing pink puffy dresses".

Red Herring

Distracting the audience with a point that might seem relevant but is actually a loosely or unrelated off-topic point or idea.

Appeal to Hypocrisy

Attempting to point out perceived hypocrisy on the part of someone holding an opposing or differing viewpoint in order to distract from the lack of strong support for an argument.

Causal

• Have you ever heard someone say, "correlation is not causation"?

It is often said when people try to extrapolate meaning from data that may or may not be related.

Here's an odd example:

Between 1996 and 2000, the US Highway fatality rate dropped steadily. The rates at which lemons were imported from Mexico increased steadily in proportion.

A causal fallacy would be to assume or present this data as an explanation for why highway deaths declined during this period without strong evidence supporting that reasoning. (Spoiler: there isn't any.)

Fallacy of Sunk Costs

There was a meme going around recently that a lot of people seemed to relate to. It said: "Don't stay loyal to a mistake just because you've spent a long time making it."

This fallacy is like that -- committing to an idea, project, etc., because you've already come so far that you get tunnel vision about seeing it through. When something is no longer working, it's time to change tracks.

Appeal to Authority

Misusing authority as strong supporting evidence when it is not.

This can be done by citing irrelevant authorities, misrepresenting authority, or treating "experts" as if they must be correct by virtue of being considered an "expert" regardless of additional evidence that may discredit or disprove the support.

Equivocation

False equivalencies is the converse to false dichotomies.

Instead of erroneously creating diametric opposition between two ideas, this fallacy creates a relation or attempts to make two things equal that are not in reality.

Appeal to Pity

Exploiting the compassion of the audience in lieu of strong support for an argument.

While well-crafted emotional appeals are an important component of rhetoric, manipulating an audience's emotions is an invalid and illogical method of supporting an argument.

Bandwagon

Using the mistaken assumption that just because an idea is popular or many people favor it as support for an argument.

This is an important moment in time for this fallacy in terms of the current cultural climate: this is the appeal made by the social-media influencer industry.

Influencers make a career of collecting followers, and companies send them free things to promote to their followers. The brands are attempting to appeal to popularity.

How to Find Balance in Argumentation

There are a lot of concerns when constructing a strong, thoughtful argument.

Rhetoric calls for an appropriate balance of appeals to logic, credibility, and emotion; however, reviewing the common logical fallacies shows that there are pitfalls to avoid along each path.

• How can you be sure you're constructing strong arguments with solid, logical supports?

An important starting consideration is that you don't seek out evidence to support your conclusion, but rather let the evidence inform the conclusion you make. Once that has been done, you're starting in good faith with a more credible basis.

When identifying supports, consider your pool of data or information, how you determined the quality of that information, and what limitations to that information exist.

Use the best resources possible to construct arguments that are well-reasoned and avoid the errors above.

• Ready to assess how well you know these logical fallacies?

Click through to the Got It? section to find out!