Logical Fallacies that are Most Commonly Used in Arguments
I'm not one to get into political or religious debates (unlike most folks you'll run across on the internet), and the following list is one of the main reasons why. But for those of you who find yourselves always tangled up in that sort of thing, the following list may be useful for you to learn. After all, you never know when an argument may suddenly break out. Just because a random forum post is about the cheese making process doesn't mean that four pages in you won't find two people arguing about evolution or American foreign policy.
This is the Internet, and it always manages to happen some way or another.
Straw Man Argument
The Straw Man Argument is arguably (ha) the mother of all logical fallacies, as it is probably one of the most common ones you'll see. A debater sets out to prove his opponent wrong, but in the process of attacking said opponent, he instead accidentally attacks a "Man of Straw"--a position of his opponent that he has misunderstood his opponent to take, while his opponent stands unscathed. He then spends the majority of the debate disproving this opinion that the opponent doesn't even have. The Straw Man fallacy is perhaps one of the most infuriating of logical fallacies, because the supporters of the arguer who has used it will claim victory when, in fact, no true debate has happened at all.
Some examples of the Straw Man Argument in action:
A book "discrediting" evolutionary theory. [source: /r/atheism on Reddit]
Child: "Can we get a dog?"
Child: "It would protect us."
Parent: "Still, no."
Child: "Why do you want to leave us and our house unprotected?" [source]
Appeal to Probablity
You'll see this one often on conspiracy theory blogs and in countless forum posts throughout the ages. Someone arguing Appeal to Probability is saying that just because something can happen, it most definitely will happen. Paranoid Stereophonic individuals have trouble with this one, so if you see someone asserting a blatant Appeal to Probability, you should probably watch what you take seriously from them in the future.
There is an argument (again, ha) that suggests that "Appeal to Probability" may not be an appropriate name for this fallacy, and I am in agreement. Appeal to Probability makes it sound like this fallacy is stating that something is likely to happen, when in reality the term means that someone is stating that just because something can happen it most definitely will. For example, if you bash your head into a wall you are likely to get a concussion. You should listen to someone who tells you not to for that reason. However, if someone tells you that shouldn't go outside because the stars may start falling from the sky, you're probably safe to leave for work that morning. Sure, it can happen, but it isn't likely. The risks (dying in a meteor shower) far outweigh the benefits (going to work and not getting fired).
Sometimes the Appeal to Probability gives good advice (like the advice in the example below to use a firewall), but its fallacy is in that it states that something that is only probably is inevitable. Sometimes protecting yourself is good, but worrying yourself to death over something that only might happen is not worth the effort.
Now that I hope I've cleared up the meaning of the fallacy that appeals to probability (and it's confusing name), here are some examples:
"There are so many religions so one of them has to be correct." [source]
"There are many hackers that spread worms through the internet. Therefore, if you use the internet without a firewall, it is inevitable that you will be hacked sooner or later." [source]
Correlation Implies Causation
Here's another one for the conspiracy blogs. Correlation Implies Causation suggests that simply because one event happened before that second event was caused by the first. Everything that happens certainly does have a cause, but far too many events occur before other events for one to pick one event and run with it without first testing all of the other possibilities involving all of the other events. Arguers of Correlation Implies Causation generally do so to further their own agenda, ignoring any other possible causes of an event that do not disprove their own hypothesis.
This fallacy also tends to arise in poorly conducted scientific studies in which important variables are not being accurately controlled, or worse, studies that do not even have a control variable at all. Remember, kids: not all studies are created equal. Anyone can conduct one.
Examples of Correlation Implies Causation include:
Studies at one time showed that women taking HRT had less coronary heart diseases. For the longest time doctors took this to mean that HRT decreased an individual's chances of CHD. Further study, however, revealed that the women who took HRT also tended to eat healthier and exercise more often than those who did not. The HRT was coincidental evidence. [source]
The Church of the Flying Spaghetti Monster asserts that Global Warming is caused by a lack of pirates sailing on the open seas because of a graph that shows the temperature of the earth going up in response to a decline in the number of pirates. [source] I know...this one is a joke, but it's just too perfect.
The Ad hominem argument is when the person debating attacks the arguer, not the argument. I'll be you've heard this one a thousand times in televised political debates and advertisements. Senator Robert Poppycock knows nothing about how to fix the economy because of his past with alcoholism. These arguments get nobody anywhere at all, and should be avoided at all cost in the name of true, useful, and progressive debate.
Politicians are not the only practitioners of ad hominem, however. How many times have you gotten into an argument with a friend and heard (or said) something along the lines of, "You have nowhere to talk about healthy food because yesterday I saw you eating a candy bar."
In other words, if I tell you that it is unhealthy for you to eat so many candy bars yet ate one myself yesterday I am a hypocrite, yes, but my statement that candy bars are bad for you is no less true because I ate one myself.
"You can't believe Jon when he says the proposed policy would help the economy. He doesn't even have a job." [source]
Hitler Card (Reductio ad Hitlerum)
This one is pretty self explanatory.
The Hitler Card vexes me more than any other logical fallacy simply because it is used so much, can turn the tide so easily, and seems to make the least sense. Hitler was a horrible person who did a lot of bad things, and it is despicable to compare his terrible hate crimes to some guy raising taxes. It's a sad world when you can win (or at least pretend you won) any argument by saying, "Hitlerdunnittoo." It's like when you're arguing with a girl and she turns on the waterworks. It's over.
You can find an example for this one just by watching the news. Seriously. Every time you hear it, just remember that by the same logical you can say washing your hair is bad because Hitler washed his hair.
- Thou shalt not commit logical fallacies
Logical fallacies are often sneakily used by politicians and the media to fool people. Don't be fooled! This website has been designed to help you identify and call out dodgy logic wherever it may raise its ugly, incoherent head.
- RationalWiki's list of Logical Fallacies
I love Rational Wiki. This link simplifies Wikipedia's list.
- Wikipedia's List of Fallacies
An extensive list of logical fallacies, both formal and informal.