Fallacies are typically considered errors in reasoning or logic. We could also consider shady practices, like willful deception, as fallacious. When a person comes to a conclusion about something, the expectation is that the steps to getting there should be clear and make reasonable sense, like showing answers in a math problem or making reasonable assumptions about what may or may not be true.
I could, for example, observe a squirrel on a lawn and, therefore, conclude that all lawns have squirrels. This may of may not be true. The point is: does it makes sense to claim that all lawns have squirrels because of one case. What follows is a list of typical fallacies that might be relevant to your own studies. I could also claim that windows are broken in riot, therefore if I encounter a broken window, a riot must have occurred (the fallacy of affirming the consequent).
Fallacies of Generalization and Causation:
Hasty Generalization: keywords: insufficiency, sample size, presumption. Coming to a conclusion based on a limited number of cases or examples or due to insufficient sample size, like the squirrel issue above. This kind of reasoning is behind prejudgement and can lead to poor and dangerous decisions.
Illustration. Let’s say you are an insurance person and you see someone with red or black hair smoking a cigarette on a street corner. You run back to the office and assert to your colleagues that the company should add hair color to their list of significant facts about people in order to determine who is at a higher risk for serious disease. We could say something like this: people with black hair engage in dangerous activity. A has black hair, therefore A engages in dangerous activity.
Post hoc ergo propter hoc (translation: after this, therefore because of this): keywords: false cause, causality, correlation. Attributing meaning or causality to an action or phenomenon because it follows another phenomenon in an observable sequence. C follows B in an observed sequence, therefore B caused C.
Illustration: First I saw the lightning, then I got hammered by the rain. Therefore, the lightning caused the rain. This is a trivial example. More significant examples might have to do with solutions to policy debates that depend on accurately determining the causes of problems, like planet warming or the reasons why squirrels hang out on lawns.
Slippery Slope: keywords: assumption, chain reaction, domino effect. D will likely happen if we do A. It is assumed that a negative event will follow from an action in this rendition of a causal fallacy. B will inevitably be the result of this or that.
Illustration: If we do as you say and ban walnuts from the party bread, next thing you know, the fruit will go next. In all seriousness, people will use the SS fallacy in real terms because in our experience A will follow B or has done so, but the argument must be as thorough as possible in support of the assertion to avoid the fallacy. We claim, for example, that “you give an inch, they take a mile.” The question to keep in mind is the potential for the appeal to fear or inevitability where things are not really so clear. Orin Cass might be onto something when he writes: “A UBI would undermine all this: Work by definition would become optional, and consumption would become an entitlement disconnected from production. Stripped of its essential role as the way to earn a living, work would instead be an activity one engaged in by choice, for enjoyment, or to afford nicer things” (par 10). However, he might also be on the slippery slope.
False dilemma: keywords: appeal to fear, insufficient choice. When only two choices are offered as a solution or outcome to a problem. Or confusing opposites with alternatives.
Illustration: We know that sometimes A is true and B is true. It could be true that removing restrictions to banned actions or substances will lead to the “destruction of the human race.” But this is not the same as saying: We can either keep this thing illegal or destroy the human race (which would you prefer?) or We can either keep drivers behind the wheel or legislate chaos onto the roads (which would you prefer?). In the false dilemma, the position is stated as an either/or not as an “if statement” or “set of” likely or reasonable consequences.
Begging the Question: keywords: circular reasoning. Asserting that something is true or right by asserting the thing itself as being true or right, asking that the audience simple accept the premise of the argument.
Illustration: We should legalize marijuana because doing so is good asserts the “position” in the place of the arguments that should follow and demonstrate that legalization is “good.” We should all eat kale because it’s just the right thing to do assumes the truth of the premise. Assuming that something is true and then moving onto something else is the simplest form of begging the question. A is A or A is B because of B.
Apples and Oranges or False or Week analogy: keywords: comparison. Often this is simply a matter of making a case that one thing is like another but there are major or significant differences that weaken the comparison or reason for making a case in the first place. If A and B are not equivalent or similar then A cannot be like B or vice versa. Or, if A requires that B and C be similar and if C and B are not similar then A is false.
Illustration: Company A, who makes soup, sees that Company B, who makes tires, has laid off 500 employees. Company A proposes to lay off 500 employees because they think this will put them into the stream of a trend. Good idea? What does soup have to do with tires? A is like B or A is B. B has property C, therefore A has property C. Is this true? Has the writer proven that A has the C property? If not, then be suspicious.
Fallacies of Diversion:
Ad Hominem: keywords: against the person, accusation as evidence. When a point or case or position is assessed as false because of the characteristics of the speaker or writer.
Illustration: Father Damien in The Exorcist is called in to removed the demon from Regan. He’s a smoker, though, therefore he’s not moral enough to do the job. Note that “smokers” are immoral people is a kind of fallacy, too, right?
Red Herring: keywords: distraction, diversion, obfuscation: Diverting away from a line of argument or heart of debate to pursue a side issue.
Illustration: We might want to make the case that texting leads to certain types of bad habits in communication. However, drawing from other potential bad habits in the language, such as repetitious “likes” or “Sos” in speech, might have nothing to do with the conventions of texting. One thing is irrelevant to other.
Ad Populum: keywords: bandwagon, populism. The attempt to sway an audience by claiming that an idea, position, or phenomenon is true or right because it is popular or commonly held. The demagogue’s favorite method and a favorite for peer pressure.
Illustration: The fallacy is usually at play when the writer or speaker lacks evidence but wants to appeal to the weight of opinion. If many people think that something is right or moral, does that make it so? If a policy is popular, a book a major money-maker, does that make the policy excellent, or the book amazing?
Straw Man: keywords: distraction, distortion, ad hominem. Appealing to an audience by asserting an easily refutable argument or position not truly held or expressed by another party. Distracting from the subject at hand by refuting an unrelated claim.
Illustration: We might argue, for example, that Person A who advocates for safer helmets in football is a person who advocates for brutality and violence to spread throughout the sports culture. Safer helmet advocates do not make the argument that they are encouraging violence. Claiming that they do invents an easily burnable argument.
Moral Equivalence: keywords: molehills, false comparison, obfuscation, ad hominem. Comparing–with insufficient evidence or over-generalization–a minor flaw or problem to a major flaw or problem . A is “as bad as” or “as good as” B where A must meet a false comparison standard.
Illustration: George Orwell wrote in the first part of his essay The Lion and the Unicorn: “An illusion can become a half-truth, a mask can alter the expression of a face. The familiar arguments to the effect that democracy is ‘just the same as’ or ‘just as bad as’ totalitarianism never take account of this fact. All such arguments boil down to saying that half a loaf is the same as no bread.” In addition, it is often the case that people will justify immoral or unethical behavior by claiming that A or B is worse, so there.
Misleading Vividness: keywords: diversion, obfuscation. Appealing to an audience by describing an action or event in exaggerated terms to convince that a problem exists.
Appeals to authority: keywords: the name drop, ad populem. Appealing to the audience by associating or relating the rightness or wrongness of assertions to experts or authorities who may not be experts or authorities in a specific area of study or profession.
Illustration: A product is argued as something special, effective, or useful. The evidence is an endorsement by a famous person. A strategy or solution is supported by one or several recognizable people as effective, good, ethical, or moral. Because “so n so” is on the side of the strategy or the policy, it must be good, because “so n so” is popular or good. Understanding the investment of true expertise is important in determining the possible soundness of an approach to problem solving or establishment of fact.
Appeals to emotion: keywords: diversion. Making a case by manipulating emotions, such as appealing to pity and fear and/or by using flattery or ridicule to sway.
You can find more fun with Fallacies at: the Fallacy Files.