The list of possible fallacies that could occur in your speech could contain hundreds, but here are some of the more common fallacies and how to spot them in an argument.
Ad Hominem Fallacy
Those who commit this fallacy attack their opponent personally, and not their ideas. They use their opponent's behavior, character, or position to discredit the claim, rather than addressing the issue.
EX) Bob Jones is a better candidate for judge because he has a family and is happily married, while his competitor Ryan Smith was just kicked of his house by his wife.
Why is the example a fallacy? Ryan's family life may have nothing to do with his ability as a judge, and the person making this argument has attacked him and his behavior rather than his ability to be a judge.
Appeal to Belief Fallacy
The arguer states that because their claim is believed by many people to be true, it is true. This fallacy does not use logic to support it's claim, but rather just states that since so many have the belief that is is right, then it must be right.
EX) A poll conducted found that 85% of people believe in God. Therefore, God is real.
Why is the example a fallacy? Just because 85% of people believe that God exists does not prove that it is true. There is no evidence in this argument to support the claim that God is real.
Appeal to Common Practice Fallacy
This fallacy is committed by those who say that since most people do this certain action, it must be morally good. Basically, everyone is doing it so it must be OK.
EX) James drive 80 mph in a 65 mph zone. Even though he is speeding and breaking the law, James believes it is OK.
Why is the example a fallacy? James justifies his speeding by saying that everyone else is doing it as well. Just because it is common thing does not make it OK and is not good evidence to support the claim that what you are doing is OK.
Begging the Question Fallacy
An arguer who comes to a conclusion without providing sufficient support and evidence to support their claim has committed this fallacy. This fallacy is also referred to as the "circular reasoning", because speakers who use this fallacy use their claim to support their conclusion without other evidence (O'Hair and Wiemann 487).
EX) Taylor states the "people only watch The Vampire Diaries because Twilight was so awesome."
Why is the example a fallacy? Taylor has given no solid evidence to lead from her claim to her conclusion. Her only evidence is "Twilight was so awesome", which is not acceptable evidence to make a conclusion because it is subjective.
Burden of Proof Fallacy
A speaker who argues that a lack of evidence against their arguments signifies evidence for their argument has used the burden of proof fallacy.
EX) Ben tells Jenny that leprechauns exist. Jenny asks how he knows this, and Ben responds by saying "no one has proved that they don't exist, so they must."
Why is the example a fallacy? Ben's only support of his argument that leprechauns exist is that no one has proved that they don't. No evidence for the opposing argument is not evidence for Ben's argument.
Confusing Cause and Effect Fallacy
Speakers who assume that events that occur together must have caused one another have committed this fallacy. Correlation does not prove causation, and therefore just because Event A and Event B occur at the same time does not mean one made the other happen.
EX) Tyler tripped and fell at the same time that Maddy dropped her books. Maddy blames Tyler for making her drop her books.
Why is the example a fallacy? Tyler's falling had no impact on Maddy dropping her books. They may have happened at the same time, but they were two separate events that had no impact on the other whatsoever.
Red Herring Fallacy
According to popular myth, a red herring, a particularly smelly fish, can throw dogs off track when they are pursuing a scent (O'Hair and Wiemann 487). Similar to the fish, speakers use this fallacy to divert attention from the original topic to an irrelevant topic.
EX) Greg gets pulled over and says to the officer "why are you pulling me over for going 10 over in a 55? I saw a guy yesterday going 25 over on this road and swerving all over!"
Why is the example a fallacy? The person Greg saw driving the day before has nothing to do with Greg being pulled over. There may be worse drivers than Greg, but that doesn't change the fact that Greg was speeding and breaking the law.
Gambler's Fallacy
Someone who uses the gambler's fallacy assumes that since something hasn't happened in a long time, it should happen soon. It is known as the gambler's fallacy because gambler's use statistics to win money and some believe that if they lose a few times, their chances of winning next are higher because they haven't won in a while.
EX) Helen is watching David play the slots machine. He has played it several times and is frustrated because he hasn't won yet. As soon as he leaves, Helen starts playing the same slot machine under the belief that since it hasn't cashed out in a long while, it is bound to soon.
Why is the example a fallacy? Helen is mistaken because the odds of winning the slot machine are the same every time you play. Just because it has not cashed out in a while does not mean it will soon. If the odds of it cashing out are 1/50 for your first turn, they will still be 1/50 on your 100th turn.
Relativist Fallacy
A speaker rejects a claim by stating that it might be true for other people but it is not true for him. The speaker is under the impression that the opposing claim does not effect him because it is not relative to him.
EX) Michael has smoked for twenty years without contemplating any of the risks. His wife, Susan, reads an article that smoking can cause many medical issues and tells Michael this. Michael tells Susan that he has never had any medical issues since he started smoking.
Why is the example a fallacy? Michael has not had any outward issues because of smoking, so he does not believe that smoking is bad for him. In reality, he may be becoming very sick and probably has caused damage to his organs without noticing yet.
Slippery Slope Fallacy
Those who use this fallacy state that point A will inevitably lead to point B, but don't give evidence to support this claim and point B is usually drastically different than point A. A speaker attests that some event must clearly occur as a result of another event without showing any proof that the second event was caused by the first (O'Hair and Wiemann 489).
EX) Jacob claims that if United States passes a law to allow gay marriage, the next thing the U.S. will be doing is passing laws to let people marry animals and inanimate objects.
Why is the example a fallacy? Jacob does not give solid evidence to support his claim that passing a law to allow gay marriage (Point A) will lead to passing laws that allow people to marry animals and objects (Point B).
Two Wrongs Make a Right Fallacy
The arguer rationalizes his actions against someone by telling himself that the person would have done the same thing to them. Usually, the people have never been in a situation like this with the other person and are basing this claim off assumptions.
EX) Sally borrows Felicia's sweatshirt at the football game and forgets to give it back that night. She finds it the next morning and decides that it's really cute and she wants to keep it. Felicia justifies her decision to keep it by believing that Sally would've done the same thing.
Why is the example a fallacy? Felicia has no evidence or reason to believe that Sally would've done the same thing in her shoes.
Biased Sample Fallacy
The speakers draws statistics and evidence from a sample that is prejudice in some way and bases their conclusion off of these statistics.
EX) Eric is trying to prove that a majority of people in Oregon make more than $60,000 a year. He decides to conduct a survey and asks two hundred people their salary. The majority of the two hundred people he chose to survey lived in the gated community of Oregon.
Why is the example a fallacy? The sample Eric chose to survey was biased because they lived in the wealthier part of town. Instead of conducting a random sample and basing his argument off of that, he chose a sample that he knew would support his claim.
Referring to my last blog on Ethos, Pathos, and Logos, avoiding using fallacies in your argument goes a long way towards building your ethos. If you can gain the trust of your audience by not trying to deceive them by using fallacies, you will be more credible and respected. You want to rely on facts, research, and your presentation to persuade your audience. If you find yourself using fallacies to support your argument, their is a good chance you are lacking solid evidence and research for your topic (O'Hair and Wiemann 489).
For more information on logical fallacies and to research other types of fallacies, visit this website.
Works Cited
O'Hair, Dan, and Mary O. Wiemann. "Chapter 16: Persuasive Speaking." Real Communication: An Introduction with Mass Communication. Second ed. Boston/New York: Bedford/St. Martin's, 2012. N. pag. Print.