If you’ve ever taken a logic and critical thinking course, you’ll have learned about logical fallacies. Logical fallacies are patterns of bad reasoning that occur so often they’re given their own special names.
Ad hominem arguments are directed at the person holding a position rather than at the position she holds. Ad populum or ‘bandwagon’ arguments claim something must be true since so many people believe it. Ad misericordium arguments, or appeals to pity, leverage support for a position by playing on another’s sympathy or guilt.
Logical fallacies can be highly persuasive, and so you’ll find them in abundance in advertising and political speeches. But they also occur in everyday conversations, including those of logicians!
Some people use logical fallacies intentionally to deceive others. But most use them inadvertently, because they sound, on the surface, quite reasonable. And they tend to work especially well for getting others to agree with some position. They’re just not reliable ways of getting at the truth.
This is not to say human reasoning is inherently defective, nor that logical fallacies are inherently deceptive. On the contrary, the human brain and its faculties work remarkably well for its purposes, which are some times social, other times evidential, and often some combination of both.
Consider this. The human brain sucks about a fifth of our glucose energy to drive slow, careful systematic thinking. As social animals living in busy environments, humans don’t have the time and energy to service this demand. And so we’re adept at using all kinds of mental short cuts. These short cuts, or heuristics, are prone to glitches, but, in familiar environments, they work well enough most of the time to disqualify us for a Darwin Award.
Logical fallacies are argument-patterns that exploit these mental shortcuts, making it all the more likely we’ll buy into a nasty piece of reasoning. But take heart. There is a defence against this fallacious reasoning, and that is to learn these patterns and practice spotting them until you can do so with very little effort. You’ll find plenty of resources via your search engine to this end.
But what I want to do here is talk about the lesser known logical fallacies, the ones you won’t find on your search engine. By ‘lesser known’ is not meant they occur less often; it just means we don’t pay them much attention. So let’s give them their due:
Arguments to Unintelligibility
Ad baffulum, appeal to incoherent speech. I can’t make heads or tails out of what you’re saying, therefore whatever you’re saying must be true.
Argument ad giggulum, appeal to the giggle. If one giggles when questioned, then whatever she says must be true.
Argument ad mumbulum, appeal to the inaudible. I’m tired of asking you to repeat yourself, or be more clear, therefore whatever you say must be true.
Arguments to Deflection
Argument ad shruggitoffulum, appeal to disinterestedness. The truth of my position is so obvious and banal that it’s not worth my explaining it to you.
Argument ad smugulum, appeal to superiority. I’m so clearly brilliant, in much the way you aren’t, that it’s not worth my breath to argue with you. Therefore whatever I say is true. (Closely related to the ad shruggitoffulum.)
Arguments to Distraction: Body Functions
Argument ad coughinum, appeal to the cough. One coughs or clears her throat incessantly until her opponent aborts the argument and accepts any conclusion as true.
Argument ad totallygrossinundum, appeal to unappealingness. One’s personal habits, such as nose picking or scab eating, causes another to accept a fallacious conclusion just to escape close personal contact.
Argument ad sputum , appeal to spit. Sometimes known as the “say it don’t spray it” fallacy. Canadian Prime Minister Justic Trudeau notes that some people “speak moistly”. Some people speak moistly as a diversionary tactic, forcing an opponent to accept her conclusion as true solely to avoid getting soaked. Covid has greatly reduced this fallacy thanks to widespread mask use.
I elucidated these ‘lesser known fallacies’ in an attempt to be funny. But are they? Each of the ‘fallacies’ I’ve sketched are not technically fallacies. However, they’re familiar patterns of behaviour. And they’re used both tactically and habitually to avoid thinking carefully about one or another’s position on some matter.
A persistent cough might be a medical condition. But it might also be a learned behaviour that has proven effective at keeping others at arms length when one doesn’t want to be challenged, and also at annoying people into acquiescence with one’s position. The beauty is few people will call someone out on her cough lest they themselves appear incompassionate jerks. Hence some little tic that has nothing to do with reasoning can have a big impact on reasoning.
I haven’t discovered anything new here. Avoidance, diversion, and deflection tactics are well-known strategic and psychological phenomena. What I’ve found interesting through this exercise is just how much influence very subtle cues have not on whether we employ bad reasoning but on whether we employ reason at all!
A raised eyebrow can be more of a deterrent to evaluating an argument than a raised fist. With a fist, I might ‘persuade’ one or, at most, a few. With a raised eyebrow, I might persuade a room. The argument ad eyebrow, appeal to disapproval. Don’t question my judgment, but you should question yours.
One take away here is that critical thinking courses might successfully teach students to recognize logical fallacies and invalid argument forms, but they’ll never arm students against the ubiquitous social behaviours that might do an end-run around such training. Hence we’re likely stuck with a lot of this near-enough, good-enough reasoning, which is only sometimes worse than no reasoning at all.