A fallacy is an argument which provides poor reasoning in support of its conclusion. Fallacies differ from other bad arguments in that many people (idiots) will mistakenly take a fallacious argument to provide good reasons to believe its conclusion.
Pointing out a logical fallacy is one of the greatest joys a person can experience. It has everything: someone you disagree with is told their argument is totally worthless, and you also get to almost say fellatio.
Fallacies are almost laughably easy to spot for anyone with even basic training in logic. For example, when people who were on the high school debating team for even a few days hear someone say "Beets are food. Food is delicious. Therefore beets are delicious," they know immediately not to trust the conclusion, because of their rudimentary logic skills. Others must depend on the basic common knowledge that beets are neither delicious nor food.
The ability to spot logical fallacies can be a blessing and a curse. A person seriously trained in logical thought is wracked with horror virtually every time one of their fellow humans makes a statement. In addition, every single celebrity, politician, and news personality ends up looking like this:
However, it typically takes some time for people who have received training in logic to realize how foolish they've been. At first, they notice only the blessing part of the abhorrent bless/curse combo that is Logic 101.
These junior philosophers revel in their new found power to spot lies of omission and accuse people they argue with of engaging in ad hominem attacks or of building "strawmen." However, they soon come to realize that now they can't not hear logical fallacies. This is unfortunate for them, as the ability to ignore logical fallacies counts as a survival skill in our society.
Someone who cannot ignore a logical fallacy will spend so much time pointing them out that they will have no time for holding down a job, finding a mate, finding a mate who holds down a job, masturbating, or holding down a mate while masturbating.
For example, both Glenn Beck and Chuck Norris commit logical fallacies at a rate of roughly 17 per minute, even while they are sleeping. Listening to both of them speak at the same time would probably make Aristotle's head explode (see Chuck Norris Roundhouse Kicks Politics (and Logic) on CNN).
They also soon notice that they are being repeatedly lied to in commercials. Luckily, this is something they can share with the rest of us, as advertisers are often ridiculously bad at concealing their fallacies (see As Seen on TV: The 10 Most Laughable Misleading Ads).
The overwhelming majority of us are not trained in logical thought and the detection of fallacious arguments. This makes us easy prey for advertising copywriters, politicians, and other professional liars.
There are a number of reasons people tend to avoid classes in logic as if they were practical seminars on the best way to shove an alligator up your ass. Some people are certain they already know how to think properly. They therefore believe that they do not need, in the words of famous dead historian Herodotus, "None of this here logic shit." It is easy to recognize one of these people. They typically look like this:
For many of us, however, the reason we do not take classes in logic is very simple: it looks boring as shit, and appears to be composed entirely of examples that even idiots with a single Masters degree can see through. Lists of logical fallacies abound in these courses, and they typically contain examples like this:
2. All of those people read the articles at Cracked.com.
3. Therefore, reading Cracked.com turns you into an idiot.
It's easy to spot the logical fallacy there. Even your slack-jacked mouth-breathing troglodyte cousin is well aware that all of those people were idiots to begin with.
However, logical fallacies in public life are rarely as straightforward as this. Instead, those wishing to sneak a logical fallacy into discourse use stealth, misdirection, and subterfuge. One extremely common method is to make relatively quotidian statements appear more interesting than they really are by the copious use of words that are both brobdingnagian and recherche.
We're not going to provide a list of logical fallacies here. There's dozens of the lousy things. If you want details on all of them, try hitting up Wikipedia.
There are a few logical fallacies that we will single out, because they're incredibly common. The first is...
Correlation Equals Causation
This is more properly termed Fallacy of False Cause. Essentially, it's any argument that asserts that one thing is definitely the cause of another, simply because the two things in question are close in either space or time.
Jenny McCarthy has recently provided many sterling examples of this in her relentless quest to break down herd immunity and kill children (see Don't Listen to Jenny McCarthy).
You Suck, and Therefore What You Say SucksOnce again, this is not the formal name. It's most commonly referred to as an ad hominem, or ad hominem attack. It is so commonly used in political circles that most politicians would have a heart attack and die if they stopped experiencing it for even one second.
Essentially, an ad hominen attacks an idea on the merits (or lack thereof) of the person making it, rather than on the argument itself. Its use in government is endemic to the point where we just wish everyone in Washington would die. But politicians break out the big guns during campaign season, allowing ad hominem attacks to reach truly transcendental (and retarded) heights (see 5 Presidential Elections Even Dumber Than This One (Somehow)).