Why fallacy is important

Try this: Show student examples of persuasive writing filled with loaded language or deeply emotional appeals like pity or disgust, then ask them about the logical basis for these arguments.

It can be eye-opening for students to see that these persuasive commercials often have little data or content. Instead, they rest their entire argument on our emotional connection with certain music and images. There are many ways to help older students improve their understanding of logical fallacies. The website Yourlogicalfallacyis.

By associating traditional logical fallacy concepts with images and easy explanations, the website helps students learn more complex fallacies like the straw man or hasty generalization. Rugnetta points out the most common fallacies and draws explanations to illustrate how they are committed, why they might seem acceptable, and why they are logical errors.

However students learn about fallacies, it is essential to get them past the theoretical and draw them into exercises identifying fallacies. I encourage them to bring these examples to class, where we discuss their findings — from the news to television to commercials.

As students begin to apply their theoretical knowledge, they develop a deeper sense of logical errors and their importance in argument building. For example:. All members of the National Rifle Association are ignorant yokels. No ignorant yokels are people whose opinions are worth considering.

Therefore, no members of the National Rifle Association are people whose opinions are worth considering. This argument is clearly valid and provably so, by standard rules of syllogism ; but, it is also clearly fallacious: it is an example of the Ad Hominem - Abusive fallacy. So, clearly, valid arguments can be fallacious. I think logicians have traditionally misunderstood the role that validity plays in the critique of reasoning.

We do not use validity to decide whether an argument is good or bad. Rather, I believe that the concept of validity serves merely to distinguish utterances that qualify as arguments from utterances that fail to qualify as arguments. The concept of validity in logic corresponds to the concept of grammaticality in grammar. A sentence that fails to be grammatical is not correctly structured, and so fails to be a sentence at all technically speaking.

Likewise, an argument that fails to be valid is not correctly structured for its type , and so fails to be an argument at all technically speaking. For Deductive arguments, the modern concept of validity tells us whether an utterance is a well-formed Deductive argument, not whether we should be persuaded by it.

A Deductive argument is well-formed when it is impossible for the premisses to be true while the conclusion is false. A doctrine of well-formedness can also be developed for Inductive and Retroductive arguments. My paper, "Deductively valid, inductively valid, and retroductively valid syllogisms," Transactions of the Charles S. Peirce Society , vol. In the extended sense, it would be true to say that all arguments, both fallacious and non-fallacious, are valid for their type , simply because any utterance that failed to be valid would fail to qualify as an argument of the specified type.

Having dispensed with the concept of validity as a criterion of good reasoning, it remains to consider what criteria should be used instead. In the above definition I have simply used the non-committal phrase "good reasoning," in the hope that it will stand in for whatever criteria we ultimately decide to adopt.

Good reasoning is reasoning that tends, in the long run, to produce true conclusions. In the end, the measure of good reasoning is that it tends to move us closer to the truth. However, a fallacy is not just any type of reasoning that might lead to a false conclusion. Even perfectly legitimate patterns of reasoning might lead to a false conclusion from time to time, simply because uncertainty is a necessary feature of the logical landscape.

Whenever we generalize from a sample Inductive reasoning we run the risk that our sample--however carefully we draw it--might not accurately represent the population from which it was drawn. Induction is notoriously unreliable, and Retroduction is worse! Even a Deduction guarantees a true conclusion only when its premisses are true.

However, for all their faults, Deduction, Induction and Retroduction, used with appropriate care, can lead us to the truth in the long run. Fallacies occur when something undermines or subverts this general tendency. Causal fallacies are informal fallacies that occur when an argument incorrectly concludes that a cause is related to an effect.

Think of the causal fallacy as a parent category for other fallacies about unproven causes. One example is the false cause fallacy, which is when you draw a conclusion about what the cause was without enough evidence to do so. Another is the post hoc fallacy, which is when you mistake something for the cause because it came first — not because it actually caused the effect. Crows must be the creators of the universe. A sunk cost fallacy is when someone continues doing something because of the effort they already put in it, regardless of whether the additional costs outweigh the potential benefits.

For example: Imagine that after watching the first six episodes of a TV show, you decide the show isn't for you. Those six episodes are your "sunk cost. No marriage. No kids. No steady job. But I've been with him for seven years, so I'd better stay with him. This is so tough, and it's not nearly as fun as I thought it would be, but I don't know.

I guess I'll finish it and get my degree. Appeal to authority is the misuse of an authority's opinion to support an argument. While an authority's opinion can represent evidence and data, it becomes a fallacy if their expertise or authority is overstated, illegitimate, or irrelevant to the topic. For example, citing a foot doctor when trying to prove something related to psychiatry would be an appeal to authority fallacy.

It's true. My computer science teacher says so. Equivocation happens when a word, phrase, or sentence is used deliberately to confuse, deceive, or mislead.

In other words, saying one thing but meaning another. When it's poetic or comical, we call this a "play on words. But my political party is planning strategic federal investment in critical programs. I said I'd never speak to my ex-girlfriend again. And I didn't. I just sent her some pictures and text messages. An appeal to pity relies on provoking your emotions to win an argument rather than factual evidence.

Appealing to pity attempts to pull on an audience's heartstrings, distract them, and support their point of view. Someone accused of a crime using a cane or walker to appear more feeble in front of a jury is one example of appeal to pity.

The appearance of disability isn't an argument on the merits of the case, but it's intended to sway the jury's opinion anyway. I know I only turned in a sentence and some clip art, but you have to understand, my grandmother suddenly died while traveling in the Northern Yukon, and her funeral was there so I had to travel, and my parents got divorced in the middle of the ceremony, and all the stress caused me to become catatonic for two weeks.

Have some pity — my grandmother's last wish was that I'd get an A in this class. I'd like to schedule a meeting with you to discuss how I can do better on our next assignment. The bandwagon fallacy assumes something is true or right or good because others agree with it. In other words, the fallacy argues that if everyone thinks a certain way, then you should, too. One problem with this kind of reasoning is that the broad acceptance of a claim or action doesn't mean that it's factually justified.