Welcome to another edition of Logical Fallacy Bootcamp, wherein I explain a logical fallacy and give a few examples to enlighten readers. Hopefully this will help folks identify logical fallacies when they encounter them in the real world, and tighten up their own thinking and spot when they might themselves be using a logical fallacy.
Today’s fallacy: Non Sequitur
The non sequitur (from the Latin “it doesn’t follow” — philosophers introduced the phrase into the English lexicon in the early 1500’s) is a logical fallacy in which a conclusion or statement does not logically follow from the previous arguments or statements made. In common everyday usage, non sequitur has also come to mean any statement that appears to randomly come out of the blue from nowhere in particular. The non sequitur of this sort is often used in media for comedic effect.
In more formal usage, non sequitur can mean not only totally irrelevant statements to the argument, but conclusions that require massive leaps of faith or logic to get there based on previous discussion or available evidence (Think of it as “A,B, and C are true, so therefore Z” with no intervening steps elaborated upon.).
Non sequiturs often appear in arguments in order to derail or attempt to reframe discussion or confuse the opposition by introducing irrelevant information or statements into the argument. The more formal leaps of logic often appear because of sloppy thinking, or because the debater is attempting to assert a claim as true without doing the work of actually providing sufficient evidence to get to that conclusion.
Let’s get to the examples.
Underpants gnomes! Let’s use that as a well known example from the animated Comedy Network series South Park. The example runs like this:
Phase 1: Collect underpants.
Phase 2: ?
Phase 3: Profit
Pretty obvious leap of logic here where somehow, collecting underpants is going to lead to profit for the gnomes, but the intervening steps to get to that conclusion are, to understate the case, a bit lacking.
For the formal examples, we can continue with a few other leaps of logic:
“Border collies are good at herding sheep. Border collies are dogs. Therefore, all dogs are good at herding sheep.”
or,
“My friend Dave is an awesome cook. Therefore, all people named Dave are awesome cooks.”
These are examples where the leap of logic is pretty obvious and don’t require much elaboration, I think.
There are some less obvious examples, such as:
John drives a BMW. John must be rich.
That sounds pretty logical, but without any more information, there is actually a big leap of logic here. Driving a BMW may be a piece of evidence that John is rich, but falls short of being enough evidence to reach that conclusion by itself. For example, maybe John works for a car dealership and it’s a car belonging to the dealership. Maybe John is living far beyond his means, is massively in debt, and in a few weeks is going to get visit from the repo man. Maybe the car belongs to his parents. And so on. The evidence of driving an expensive car is just too slim of a volume of evidence, without other supporting evidence, to reach the stated conclusion.
And of course, the informal non sequiturs can stand out for being so random or absurd or out of place:
(With apologies to the Monty Python folks) here is an example from Monty Python’s Life of Brian:
Pontius Pilate: The little wascal has spiwit.
Centurion: Has what, sir?
Pontius Pilate: Spiwit.
Centurion: Yes, he did sir.
Pontius Pilate: No, no. Spiwit. Bwavado. A bit of dewwing-do.
Centurion: Oh. Uh, about eleven, sir.
The centurion’s confusion about what Pilate is talking about leads him into a non sequitur, with a response that makes no sense to the rest of the conversation.
That’s it for today, folks! Tune in next time when we visit the Appeal to Ignorance fallacy!
P.S. I am rapidly coming up on a major surgery scheduled for midweek next week that involves some major rearranging some plumbing and carving on some major organs (btw, did I mention that cancer SUX?). With that in mind, I’ve got some installments of my series already in the pipeline ready to go in the event that I’m indisposed to write them during my recovery. Or, worst case scenario, I could be speaking to you from The Great Beyond. If so, well, it’s been a pleasure folks, and either way I guess I can at least say “I’ll see you on the other side.”
Logical Fallacies Bootcamp is an ongoing series. If you’re a latecomer to the series or have missed a past post in the series, or simply want to revisit a past post, here are the posts in the series so far:
Logical Fallacies Bootcamp: The Strawman
Logical Fallacies Bootcamp: The Slippery Slope
Logical Fallacies Bootcamp: Begging the Question
Logical Fallacies Bootcamp: Poisoning the Well
Logical Fallacies Bootcamp: No True Scotsman!
Logical Fallacies Bootcamp: Ad Hominem
Logical Fallacies Bootcamp: False Dilemma