As skeptics, we strive to be as logical as possible. One of the best ways to do this is to learn what logical fallacies are and avoid using them. This is an excellent thing to do, however there is a problem: Many skeptics have diligently learned what the fallacies are, but end up incorrectly identifying them. These false positives are understandable, but we would all benefit from putting some extra effort into our analysis. Here are a few of the fallacies that I think fall into this trap.
No True Scotsman
What it is:
Someone commits this fallacy by shifting a definition of something in an attempt to side-step a counterexample that doesn’t support their conclusion.
The term derives from an example put out by Anthony Flew in which a Scotsman denies that a rapist could be Scottish because Scotsmen don’t do such things. No True Scotsman is a very tempting fallacy to fall prey to because we want to be the good guys. We want our team to be the one helping people, so it’s only natural to want to exclude people we disapprove of from our group.
What it looks like in the wild:
“The guy killed 70 people in cold blood, he clearly isn’t a True Christian.”
When it isn’t a fallacy:
If you are arguing a position that is tightly defined, an example deviating from that is fair to say is not applicable. When I pontificate about the awesomeness of triangles and someone says the worst kind of triangle is a circle, it’s fair to say they have it wrong. If the Christian you are talking to defines “Christian” in a particular way that excludes all murderers, that’s fine if they spell that out. But you are then free to point out that they are using a narrow definition that you haven’t seen before. Or you could ask them to define “Christian” from the outset.
It’s also not a fallacy if you have access to a Scotsman Detector or some kind of Scotsman centrifuge that can sort out the actual Scotsmen.
Ad Hominem
What it is:
An ad hominem attack is when you disparage a person’s character rather than the argument they made and infer from this that the person’s position is false. Suppose you are arguing with a believer in alternative medicine who is claiming that acupuncture cures deadly brain tumors. In a situation like that you should be addressing whether or not their claims match reality rather than their goofy haircut, even when it’s a really goofy haircut.
What it looks like in the wild:
“Don’t listen to Jenny McCarthy when she talks about vaccines. She’s just a dumbass.”
When it isn’t a fallacy:
Disparaging the character of a proponent of pseudoscience who is also a bad person, such as Stanislaw Burzynski, in addition to criticizing their faulty arguments is not a fallacy at all. Ineffectual treatments are one issue to criticize him on, but his lack of morals is another one that also needs to be addressed. A good rule of thumb is to see how the sentence works with “therefore” added to it. “Burzynski is a maggot infested ghoul who bullies teenagers, therefore don’t trust his claims about antineoplastons and cancer” doesn’t work but “All the scientific evidence and the consensus of the medical community goes against Burzynski’s claims, and he’s a shitty person to boot” works just fine.
In some debates the character of the participants is the very heart of the issue. Being patient and charitable with disagreements on values is a useful approach for some circumstances, and with some people, but there are occasions where you will meet people who are not deserving of a hand-holding, charitable walk-through of the issue. If someone is saying a bunch of racist garbage, sometimes the appropriate thing to do is to point out that their behavior is racist. This is a character flaw that they should be fixing. If you call them on it, you will be accused of using an ad hominem attack. But when the question is actually about the morality of that person, it is justified.
Argument from Authority
What it is:
Whenever someone invokes an expert to trump the analysis of their opponent.
What it looks like in the wild:
“My pastor said that evolution is a lie from Satan.”
When it isn’t a fallacy:
The problem with rejecting all arguments from authority is that we run the risk of falling into anti-intellectualism or becoming self-important know-it-alls. The fact is, there are people who know shit that you don’t know. I can read about medicine all damn day, but if an M.D. tells me I got it wrong, it may be reasonable to ask for a second opinion, but it is not reasonable to utterly reject their opinion as an mere argument from authority.
The easiest way that I’ve found to defer to people with expertise while not accepting claims on faulty grounds is three fold:
1. Make sure that the person is an expert on the subject in question. Don’t take an English professor’s word on whether or not the Big Bang was a thing. If that professor has opinions about semi-colons though…
2. Make sure that the field they are an expert in is a real thing. Alleged psychics are “experts” on talking to dead people. Is there a good reason to think that their field of expertise is describing something real though? This is actually a difficult task to do on the fly, but a shortcut could be to see what the experts in related fields think. For example, do the experts in the field of psychology or neurology tend to believe in psychic powers? Their fields would be impacted by such a thing being real. I’d go into more detail on how to determine the validity of a field, but that could easily become another post. Or even a full book.
3. Look at what the plurality of experts in that field think about the subject. You can find two or three geologists who think Noah’s Flood explains the Grand Canyon. Do the majority of other geologists share this view? (Hint:Fucking of course not) You will find that there are circumstances where a genuine field of study does not have a consensus on a subject. When this happens, the wisest thing to do is to remind yourself not to invest too much in any one conclusion. Then make some popcorn and watch the scientific process sort it out. This may take several years, so I would advise making at least two bags of popcorn.
Just remember that your entire life is full of claims that require you to–at least provisionally–accept the conclusion of experts.
Godwin’s Law
What it is:
According to the Mike Godwin, who coined the term, “As the length of an online discussion increases, the probability of a Hitler/Nazi comparison approaches 1.” As an informal fallacy, it is used to show that someone is using extremely hyperbolic comparisons and is in fact a common example of the aforementioned Ad Hominem.
What it looks like in the wild:
Pretty much every sentence about President Obama on World Net Daily and Breitbart.
When it isn’t a fallacy:
If the person in question is 1. Named Adolf, 2. Advocating for policies that that are very similar to that of Hitler’s, or 3. Currently invading Poland.
The Straw Man
What is it:
Mischaracterizing your opponent’s argument so that it’s easier to argue against.
What it looks like in the wild:
“You atheists are all a bunch of baby-eating communists who want to put Christians like me in prison camps!”
When it isn’t a fallacy:
Sometimes your arguments will aren’t so great. And I don’t mean “you” rhetorically, I mean that you, the reader of this sentence, will have terrible arguments. You’re human, that happens. If someone repeats your argument back to you, there can be a tendency to think, “But that’s just a Straw Man, my real opinion is way cooler than that!” If you have that reaction, take a moment to re-examine your position and make sure that the characterization is not valid before dismissing the criticism as a Straw Man. If you’ve ever seen a debate between a believer and an atheist, you’ve seen this fallacy announced inappropriately, probably from both parties at various points. I remember arguing with my best friend after Skepticon 2 about whether or not the Flying Spaghetti Monster or the Invisible Pink Unicorn were Straw Men. The only real difference between those views and real religious views is the tone. If people talked about the beer volcano in FSM heaven with the same seriousness of the boring alcohol geology-free Heaven, you’d see that as truth claims they are on equal footing. If you point out that the concepts within a religion are absurd, that isn’t a Straw Man, it’s perspective.
The takeaway from this is that enumerated fallacies are a great heuristic and can show you the flaws in your reasoning as well as the reasoning of others, but they are not a replacement for critical analysis nor are they a set of commandments handed down from Lord Planet-Maker.
Besides Wizards and Bees 