In fallacies of relevance the premises simply fail to support the conclusion—they are irrelevant to the conclusion being drawn. For example: “Mickey Mouse loves Camembert cheese; therefore you should buy some today!”
There are eight kinds of fallacies of relevance that we will consider.
The Ad Hominem Fallacy
The ad hominem The ad hominem (“personal attack”) fallacy occurs when there is an attack on another person (the source of an idea), instead of the person’s argument (the idea itself). fallacy occurs when there is an attack on another person (the source of an idea), instead of the person’s argument (the idea itself).
This can take the form of discrediting because of gender (“She’s a woman, what would she know about hockey?”), age (“You’re a college student, what would you know about Medicare?”), nationality or ethnicity (“Don’t pay attention to Raphael—he’s French—and undoubtedly ignorant about Chinese food”), or other aspects that are personal parameters.
The ad hominem circumstantial (“guilt by association”) fallacy involves an attack on a person’s credibility because of vested interests or social affiliations. Because of the circumstances, the person cannot possibly be impartial—or so it is implied.
Of course the representative from Prince Edward Island opposes the potato surcharge—he’s from the biggest producer of potatoes east of Ottawa. He’s bound to be in their pocket!
The fallacy of tu quo occurs when there’s an attack on a person because they don’t follow their own advice or “practice what they preach.”
Ahmad : Will you please slow down, Lisa? You’re driving 20 miles over the speed limit, which is dangerous in the rain. I’m scared!
Lisa: I don’t have to listen to you. You got a speeding ticket last month. Point your finger at me and four point back at you!
More FALLACIES OF RELEVANCE
Argumentum Ad Baculum
(Appeal to Force or Coercion)
The ad baculum fallacy occurs when force, threats, or coercion is used in an attempt to persuade. This includes verbal or sexual harassment, blackmail, extortion, or bribery.
“ Nice work Tim. Come to my hotel room tonight—we’ll discuss promotion options in a more intimate setting.”“No thanks, Marilou, and if you don’t give me a raise, I’ll make sure you live to regret it.”
(Irrelevant Appeal to Pity).
This fallacy occurs when there is an irrelevant appeal to pity or to sad circumstances to get a conclusion accepted.
“ Dr. Lee should get the Innovation in Engineering award—he’s a nice man and just lost his wife and two children in a freak accident in Fresno.
Ad Populum (Bandwagon fallacy)
This fallacy occurs when there is an attempt to persuade using popular appeal (“Most people eat donuts, why don’t you?”, the masses, or patriotism, rather than giving good reasons for the conclusion. A variation is “Snob appeal”—to be in with the “in-group”.
“ FOR EXAMPLE:
“ You shouldn’t be looking at Volvos—buy an American car and support your country!”
Argumentum Ad Verecundiam
(Improper Appeal to Authority).
This fallacy occurs when there is an attempt to persuade based on the endorsement of a celebrity or other not an expert in the field in question.
“ Keanu Reeves is a vegetarian—you should consider following his example !”
FALLACIES OF RELEVANCE continued
FALLACIES OF PRESUMPTION
This is the second category of fallacies. What makes fallacies of presumption unsound arguments is that they contain an unstated unwarranted assumption that causes the argument to sink.
Fallacy of Accident
The fallacy of accident occurs when a general rule or principle is applied to a special or exceptional case—where the rule simply does not apply. The unwarranted assumption is that the rule applies without exception.
FOR EXAMPLE: “My mother said I should always tell the truth, so that means I should tell my neighbor Myron that his diet isn’t working and he should get liposuction!”
(Appeal to Ignorance)
This fallacy occurs when it is argued that something is the case (either true or false) simply because you cannot prove otherwise. “if you can’t prove me wrong, then I must be right!”
My physics professor is an alcoholic—you have evidence that I'm wrong, so I must be right!
More FALLACIES OF PRESUMPTION
This fallacy occurs when a generalization or moral principle is drawn on the basis of too small a sample or an atypical case.
Twenty five nuns interviewed by the dietician preferred dairy to soy. Therefore, all nuns must prefer dairy to soy. Toss out the tofu!
The fallacy of biased statistics occurs when an inference is drawn on the basis of a sample that is not diverse enough. That is, the sample is not representative of the target population.
“ 85% of toddlers prefer a bottle of warm milk at bedtime. Therefore, 85% of all children prefer a bottle of warm milk at bedtime.”
Bifurcation (“False Dichotomy”)
The fallacy of bifurcation is a often called a false dichotomy by reducing a choice to only two options when, in fact, more options exist.
“ Either take the word of a madman or take action to defend the American people. “
Complex Question (Trick Question)
This fallacy takes the form of a question in which two questions are rolled into one. It is impossible to answer the question without, at the same time, answering a hidden, unasked question—or affirming an assumption that is being made.
“ Have you always been a blabbermouth?”
FALLACIES OF PRESUMPTION Con.
Post Hoc (“After This Therefore because of This”)
The post hoc fallacy asserts a causal connection that rests on something happening earlier in time. The fallacy goes like this: Because something precedes something else means that it must then cause the later thing to happen. No evidence given to support such a causal link.
Whenever the team is on a winning streak, Coach Sanders wears the same tie to each game. The Salmon Bellies won the last three games, so Coach Sanders’ lucky tie must be working!
This fallacy occurs when an irrelevant line of reasoning is intentionally used to divert people away from the topic at hand—e.g., when someone purposely shifts the subject of the conversation to avoid an incriminating line of questioning. It’s called a red herring , because a stinking little herring (fish) is an effective way to lead the hound dogs off the scent.
Amy: Honey, what's this love letter from your secretary that I found in your pocket?
Mike: Oh sugar, my sweet pea, you have made the most delicious pot roast I ever ate in my life—what ingredients did you put into this heavenly gravy? And how did you find such tasty blueberries
to accompany this feast?
More FALLACIES OF PRESUMPTION
Slippery Slope Fallacy
T his fallacy posits a causal chain—arguing that if we allow this to happen, a series of worse things will come about, taking the form of a downward spiral. The claim is that allowing the first things will lead to us down a slippery slope.
-> There is an unstated assumption that the first in the causal chain leads to the second and to the third, and so on.
If you punish students for cheating on exams, that will lead to punishment for misquoting authors, which, will lead to penalties for spelling errors or even one typo! There should be no university policy against cheating!
Straw Man Fallacy
The straw man fallacy involves unfairly diminishing or distorting the opposition so one can stand out in comparison. The comparison attempts to denigrate the opponent’s position so the audience would be crazy not to select the contrasting view!
It can take one of two different forms:
1. When an opponent's position is presented as so weak or extreme that it’s indefensible
2. When an attack is made on the weakest of a variety of arguments to contrast with one’s own, seemingly more defensible, position
Students these days object to being searched for drugs. We must realize, however, that if we don't search them, then students will be peddling drugs at school and drug abuse will be rampant.
And more… FALLACIES OF PRESUMPTION
Begging the Question
Begging the question is a fallacy consisting of circular reasoning: the speaker assumes what their trying to prove. So what happens is that the conclusion just reaffirms what has already been said, e.g., by rewording one of the premises or using a synonym for one of the terms.
People should get paid for studying for logic exams, because human beings deserve a salary for studying logic. [getting paid = getting a salary].
Even More … FALLACIES OF PRESUMPTION
Here, biased language stacks the deck with language slanted in one direction or another.
Question-begging epithets are either a euphemism (deck is stacked by praise) or a dyslogism (name-calling).
You should believe Mr. White on patriotism, because he is a hard-working American, with an appreciation of the sacrifices of others.
“ Professor Stewart’s ideas for rebuilding the downtown core seem off-base—he’s really not to be trusted—he’s too slimy for words. ”
Fallacy of Misleading Vividness:
This fallacy occurs when strong evidence is overlooked because of a very striking (vivid) counterexample. However, the personal anecdote or testimonial can be very persuasive.
Camille: “ Given the high rates of lung cancer among smokers, it seems obvious that smoking is the root cause.”
Naji: “Really? Uncle John smoked like a chimney and he lived to 93 years of age and died of a gangrenous foot. That shows you all those statistics don't mean nothing and you should smoke if you want to.”
False Analogies & Imperfect Analogies
The fallacy of false analogy occurs when a comparison is drawn between two different things, but there are few relevant similarities between them; thus creating the false analogy.
The strength of any analogy rests on the relative weight of the similarities and differences between the two things being compared. When there are only trivial similarities, the false analogy sinks the argument.
Be careful: There are usually some similarities between one thing and another; so you could think of this as an imperfect or very weak analogy, rather than completely false.
“ A good woman is just like a nice car; she is under your control and makes your life a lot easier.
A good man is like a bowl of buttered popcorn: he is comforting and doesn't talk back.”
FALLACIES OF AMBIGUITY
This fallacy occurs when different meanings of a word or phrase are used in argument.
The resulting ambiguity leads to an incorrect conclusion being drawn. This is also known as a semantic fallacy.
A special kind of equivocation has to do with “relative terms”— which have different meanings in different contexts (like “tall” or “big” or “small”).
We also see equivocation playing on the sound of a word.
Title of article in USA Today : “Ex-gymnastics stars understand flip side to expectations and glory”
How do you make antifreeze? Steal her blanket!
More FALLACIES OF AMBIGUITY
The fallacy of accent occurs when, because of the way a word or phrase is visually or verbally emphasized, we are led to drawing an incorrect conclusion.
This includes the repetition of a word or phrase that creates an ambiguity. Another way the fallacy of accent occurs is when someone misquotes or takes something out of context.
FREE MONTH’S RENT if you lease an apartment for 10 years.
This fallacy occurs when an ambiguity is created by a faulty grammatical structure of a sentence. Due to the ambiguous sentence, more than one interpretation is possible and, thus, an incorrect conclusion may be drawn.
This is also known as a fallacy of syntax.
Include your children when baking cookies. Kids make nutritious snacks. Drunks get nine months in violin case.
This fallacy occurs when it is inferred from what is true of the parts or members of something that is true of the whole thing (or organization).
Janet and Bill are each so nice! They should get married—they’d be a great couple!
The last of our FALLACIES OF AMBIGUITY
The fallacy of division occurs when we infer that what is true of a whole is also true of its parts or members. This is the opposite of composition.
The Lakers were great last night—that must mean team member Pau Gasol was in top form!
The Stomping Frog bluegrass band are the best. Therefore, Lulu Mae, the back up singer, is beyond reproach.
Fallacy of Affirming the Consequent
This fallacy starts with a conditional claim and then argues that, if the consequent is true then the antecedent is also true.
Its form is: If A then B. B is true. Therefore A is also true.
Fallacy of Denying the Antecedent
The fallacy of denying the antecedent starts with a conditional claim and then argues that, if the antecedent condition is false then the consequent effect cannot be true.
Its form is: If A then B. A is not true. Therefore, B is not true either.
Fallacy of Affirming the Consequent: If I eat too many donuts, my diet will be ruined. My diet was ruined. Therefore, I must have over did it on the donuts.
Fallacy of Denying the Antecedent: If Amanda runs around the block, she’ll be tired. Amanda didn’t run around the block, so she must not be tired.