So, we are now moving on to more fallacies. It’s worthwhile to note here that not every fallacy can be ultimately defined, and the taxonomy presented in the book simply lists some of the most common fallacies. The idea is for you to recognize bad reasoning around you—in newspapers, online, etc.—not to rigorously memorize these fallacies. Still, you are going to have to be able to recognize examples of various fallacies for the exam. The important point is that you’re able to explain why you’ve chosen to call something a fallacy—this is what will get you the points.

Ad Hominem

As the book points out, this is one of the most common fallacies of all time. In Latin, ad hominem means “against the person.” This occurs when someone attacks the person stating a claim or making an argument rather than the claim or the argument itself. It might be true that someone is an idiot if you think he is, but it doesn’t follow that his argument is idiotic. Likewise, just because you think someone is brilliant it doesn’t follow that his argument is always brilliant (as a matter of fact, brilliant people can come up with some ridiculous ideas).

Here is a very simple example: “Maria can’t even spell so her claim about how much our country needs good healthcare must be false.” Do you see what’s happened? Maria’s claims about health care shouldn’t depend on whether or not she can spell. It’s true that a person’s circumstances can cause us to be skeptical about someone’s claim—if, say, someone with no education is making complex claims about weather patterns—but it should not cause us to reject the claim right off the bat.

There are a few varieties of ad hominem, but I will let you read about those in the text.

Straw Man

The straw man fallacy is also very common, particularly in political debates. Think about this one literally. A man made of straw is easy to push to the ground. A real man is harder to push to the ground. What happens in this fallacy is that someone builds up someone else’s position like it’s made of straw, then easily knocks it down. In other words, someone attributes a false position to an opponent, then easily attacks that false position. If he had described the true position, it wouldn’t be so easy to knock down.

Sometimes the straw man fallacy aims to make someone’s argument or claim look downright ridiculous. For example: “This is what communists actually believe…” “This is what republicans actually believe…”

Here’s a full example of a typical straw man: “Bill thinks God is in everything. But if God is in everything then my pencil is God and I should worship it. This is idiotic. So God can’t be in everything.” Here the belief that God is in everything is equated with the need to worship—this is a mischaracterization of pantheism, the belief that God is in everything.

False Dilemma

The false dilemma fallacy happens a lot in everyday conversation. Consider the following. You’re sitting at home watching TV. Your roommate comes home from work and asks you if you want to go out and get a few drinks. You tell him that you’re a bit tired and that you just want to stay in. He responds with this: “Look, either you can stay in for the night and be a loser or you can go out with me and have a good time.” What’s the problem with this statement? The problem is that your roommate has given you the illusion that there are only two choices: stay in and be a loser, go out with him and have fun. This is a false dilemma fallacy. Cleary, there are other options besides the ones your roommate has presented. You could stay in and not be a loser, or go out with someone else besides your roommate, or go to another friend’s house and play games.

The crux of the false dilemma is that only two options are presented when there are, in fact, other options. The problem with the false dilemma is that it’s an attempt to simplify the world in areas where the world is clearly complex. Here’s another common one that is often used by leaders: “Either you’re with us, or you’re against us.”

Note that there are cases where there are only two choices about something; such cases are not false dilemma fallacies. For example: “Either you are Paris Hilton or you are not.” There are only two possibilities here.

Note: There are two sub-varieties of the false dilemma discussed in the text.

Slippery Slope

My father used to tell me about something my grandmother (his mother) used to do when he was growing up. Anytime one of her sons would catch a cold, she’d assume the worst. She’d say, “Now that Bobby’s got a cold, he’s going to get pneumonia, then he’s going to go to the hospital, then we’ll be attending his funeral.” Now, this is my interpretation of what my father told me, but the point is that my grandmother always thought one thing would lead to another, and that thing would lead to another, etc.

This sort of thinking is what’s known as a slippery slope fallacy. It’s a fallacy because there is usually no reason to think that the chain of events given will occur. Typically, the first event is something simple, but then the ending event is something drastic: “If you start smoking, then you’re going to start drinking. If you start drinking, then you’re going to get into harder drugs. If you get into harder drugs, you’re going to get into heroine. If you get into heroine, then you’ll be addict and you won’t be able to function in society.”

Notice that, in some cases, there are reasons to accept that one event will lead to another. So the form of the typical slippery slope is not always a fallacy. But it is up to the person making the argument to explain how the events are linked. If it can’t be explained logically, then it’s a fallacy.

Misplaced Burden of Proof

What if you were to say this to your friend: “I think God exists and I can prove it using logic.” Then your friend were to say, “How could you possibly do that?” Then you were to say, “How? Well, how can you prove God doesn’t exist using logic?

What’s happened here is tricky, and it happens often in conversations without either person realizing it. If you make a claim about something, it is on you to prove that the claim is true. If you say something is the case, you must show how it’s the case. What happened above is that you shifted the burden of proof to your friend, when in fact it was on you. You claimed that you could prove God exists using logic, so it was on you to do so. Your friend never claimed that he could prove God didn’t exist.

This is misplacing the burden of proof. We make claims all the time about the world, and sometimes people ask us to explain how we know the claims we are making. When this happens, it is on us to explain it, not them. A common form of this argument is known as the appeal to ignorance. The appeal to ignorance basically says, “You can’t prove it’s false, so it must be true.” Or it says, “You can’t prove it’s true, so it must be false.”Again, if you make a claim that something is false, it’s on you to show how it’s false. The fact that someone else can’t prove your claim to be true doesn’t make it false. This fallacy exploits the things about the world that we don’t know.

Notice that both of the following are fallacies: “You can’t prove God doesn’t exist, so he must exist.” “You can’t prove that God does exist, so he must not exist.”

Often, people who understand logic well—like lawyers and politicians—will deliberately misplace the burden of proof to make their opponent look bad. They know the burden of proof is on them, but they want to shift focus away from themselves so they purposefully commit a burden of proof fallacy to catch their opponent off guard. Now that you’ve taken this class, you can arm yourself against such people!

Begging the Question

The begging the question fallacy is sometimes referred to as reasoning in a circle, or circularity. This is because, in this fallacy, the arguer tries to get you to accept the very thing he’s trying to prove. The failed argument essentially looks like this: “You should accept X because of X.” However, the terms used are typically clothed in different language so that it doesn’t seem to be repeating the same point. In logical terms, begging the question says the same thing in the premises as it does in the conclusion.

Here’s a common example: “God exists because the bible says so. And we know that the bible is an authoritative source of information, because it was divinely inspired.” It is implied that divine inspiration is the result of the existence of some sort of God. So this is basically saying, “We know God exists because God exists.” This is begging the question, reasoning in a circle, assuming what is trying to be proved.