Logical Fallacies (and a bit more) #
If you’ve been on the internet for more than about a quarter of a second, you’ve likely been accused of a whole host of logical fallacies. Unfortunately, most people really don’t understand what they’re saying and often use a lot of these incorrectly. On the other hand, you also likely encounter
politicians people using these fallacies on a regular basis as well, and it’s nice to be able to call them out on it. This page is going to cover a fair amount of the most common and attempt to give you examples of when they apply and when they don’t.
Almost all of the content on this page is ripped from Wikipedia, but there’s some YouTube videos and thoughts of my own in here too.
If you’d like something more visual, I recommend reading this Illustrated Book of Bad Arguments.
Argumentum ad populum #
Argumentum ad populum (Wikipedia) also know as the ‘Bandwagon fallacy’
In argumentation theory, an argumentum ad populum (Latin for “appeal to the people”) is a fallacious argument that concludes that a proposition must be true because many or most people believe it, often concisely encapsulated as: “If many believe so, it is so”.
Argument to moderation #
Inflation of conflict – arguing that, if experts in a field of knowledge disagree on a certain point within that field, no conclusion can be reached or that the legitimacy of that field of knowledge is questionable.
For example, if most of science says there’s 31 elementary particles, but some fringe scientists claim there are 42, that doesn’t mean the answer has to be somewhere in between.
Similarly, if most people think the Earth is flat, and some small fringe group of heathens think the earth is round, that doesn’t make make the popular opinion right.
Slippery slope #
“If we let the gays marry, what’s next, letting people marry horses!?”
The Slippery-er slope #
Not everything is a slippery slope. If there is actual evidence that one action may lead to future, worse action there is a good reason to take it seriously:
“If we allow the government to spy on suspected terrorists without a warrant, they may spy on everyone”
Begging the Question #
This is just a type of circular reasoning, think claims like
“Chocolate is an aphrodisiac because it makes people horny”
Well, no, you just restated the definition of aphrodisiac. That’s how most ‘begging the question’ works, by using the definition of a word to support a claim.
Cherry Picking #
Cherry picking, suppressing evidence, or the fallacy of incomplete evidence is the act of pointing to individual cases or data that seem to confirm a particular position while ignoring a significant portion of related and similar cases or data that may contradict that position.
Sampling Bias #
In statistics, sampling bias is a bias in which a sample is collected in such a way that some members of the intended population have a lower or higher sampling probability than others. It results in a biased sample, a non-random sample of a population (or non-human factors) in which all individuals, or instances, were not equally likely to have been selected.
Often, studies are WEIRD, that is people from a Western, Educated, Industrialized, Rich, and Democratic background are surveyed, this is a type of sampling bias, as the answers to a question might be different depending on if people from the US are surveyed or if people from Haiti are surveyed. Of course, the sampling bias can be much less obvious than that:
Say you wanted to study rates of COVID spread in a community, if you’re only looking at the population of people that go to get tested, the infection rate will look artificially high as if somebody doesn’t have symptoms why would they go get tested?
Survivorship Bias #
McGeddon, CC BY-SA 4.0, On Wikipedia
Survivorship bias or survival bias is the logical errorof concentrating on the people or things that made it past some selection process and overlooking those that did not, typically because of their lack of visibility. This can lead to some false conclusions in several different ways. It is a form of selection bias.
For example, if three of the five students with the best college grades went to the same high school, that can lead one to believe that the high school must offer an excellent education when, in fact, it may be just a much larger school instead. The question cannot be answered without looking at the grades of all the other students from that high school, not just the ones who made the top-five selection process.
Sunk Cost #
Escalation of commitment is a human behavior pattern in which an individual or group facing increasingly negative outcomes from a decision, action, or investment nevertheless continues the behavior instead of altering course. The actor maintains behaviors that are irrational, but align with previous decisions and actions.
Basically, people get determined and don’t want to feel like their prior time or money was wasted.
Pareto Principle #
The Pareto principle states that for many outcomes roughly 80% of consequences come from 20% of the causes (the “vital few”). Other names for this principle are the 80/20 rule, the law of the vital few, or the principle of factor sparsity.
Mathematically, the 80/20 rule is roughly described by a power law distribution (also known as a Pareto distribution for a particular set of parameters, and many natural phenomena have been shown to exhibit such a distribution. It is an adage of business management that “80% of sales come from 20% of clients”.
The Pareto Principle is derived from Zipf’s Law (Wikipedia),
Zipf’s law is an empirical law formulated using mathematical statistics that refers to the fact that many types of data studied in the physical and social sciences can be approximated with a Zipfian distribution, one of a family of related discrete power law probability distributions.
Ad hominem #
Typically this term refers to a rhetorical strategy where the speaker attacks the character, motive, or some other attribute of the person making an argument rather than attacking the substance of the argument itself. This avoids genuine debate by creating a diversion to some irrelevant but often highly charged issue. The most common form of this fallacy is “A makes a claim x, B asserts that A holds a property that is unwelcome, and hence B concludes that argument x is wrong”.
For example “Bob says that being gay is okay, but Bob is an atheist, so clearly he’s wrong”
Appeal to authority #
“God said it is true, so it is”
“If it’s illegal it’s immoral”
I’m entitled to my opinion #
I’m entitled to my opinion or I have a right to my opinion is a logical fallacy in which a person discredits any opposition by claiming that they are entitled to their opinion. The statement exemplifies a red herring or thought-terminating cliché. The logical fallacy is sometimes presented as “Let’s agree to disagree”. Whether one has a particular entitlement or right is irrelevant to whether one’s assertion is true or false. Where an objection to a belief is made, the assertion of the right to an opinion side-steps the usual steps of discourse of either asserting a justification of that belief, or an argument against the validity of the objection. Such an assertion, however, can also be an assertion of one’s own freedom or of a refusal to participate in the system of logic at hand.
This fallacy, is a bit different from the others as it’s not so much a breaking of logical rules so much as willful ignorance and stupidity. It’s often used to end arguments to avoid further conflict, which one one thing, but other times it’s used outright to stop decent and encourage people to stick to views without letting them be challenged, which is incredibly dangerous. It’s exactly what lets hate like homophobia and bad ideas, like anti-vax, spread.
Straw man #
The straw man fallacy occurs in the following pattern of argument:
- Person 1 asserts proposition X.
- Person 2 argues against a superficially similar proposition Y, falsely, as if an argument against Y were an argument against X.
[Person 1]: We should relax the laws on beer.
[Person 2]: No, any society with unrestricted access to intoxicants loses its work ethic and goes only for immediate gratification.
Whataboutism & Moving the Goalposts #
Whataboutism, also known as whataboutery, is a variant of the tu quoque logical fallacy that attempts to discredit an opponent’s position by charging them with hypocrisy without directly refuting or disproving their argument.
Moving the goalposts is an informal fallacy in which evidence presented in response to a specific claim is dismissed and some other (often greater) evidence is demanded. That is, after an attempt has been made to score a goal, the goalposts are moved to exclude the attempt. The problem with changing the rules of the game is that the meaning of the result is changed, too.
False Dichotomy/Dilemma #
A false dilemma (sometimes called false dichotomy) is a type of informal, correlative-based fallacy in which a statement falsely claims or assumes an “either/or” situation, when in fact there is at least one additional logically valid option.
“Either you’re against abortion or you love murdering babies!”
… or you’re just pro-choice but still don’t want anyone to be in a situation where the need an abortion in the first place.
Appeal to Ignorance #
Argument from Ignorance (Wikipedia), hand shortened version below:
Argument from ignorance also known as appeal to ignorance (in which ignorance represents “a lack of contrary evidence”), is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false or a proposition is false because it has not yet been proven true.
- “I took a placebo pill and now my symptoms are completely gone. The placebo cured my symptoms.”
Absence of evidence
These examples contain or represent missing information.
- Statements that begin with “I can’t prove it but …” are often referring to some kind of absence of evidence.
These examples have the potential for “false negative” results.
- When the doctor says that the test results were negative (a month later the test is positive).
Evidence of absence
These examples contain definite evidence that can be used to show, indicate, suggest, infer or deduce the non-existence or non-presence of something.
- One very carefully inspects the back seat of one’s car and finds no adult-sized kangaroos.
Arguments from ignorance
Draws a conclusion based on lack of knowledge or evidence without accounting for all possibilities
The Texas Sharpshooter #
The Texas sharpshooter fallacy is an informal fallacy which is committed when differences in data are ignored, but similarities are overemphasized. From this reasoning, a false conclusion is inferred. […] A Swedish study in 1992 tried to determine whether power lines caused some kind of poor health effects. The researchers surveyed persons living within 300 meters of high-voltage power lines over a 25-year period and looked for statistically significant increases in rates of over 800 ailments. The study found that the incidence of childhood leukemia was four times higher among those who lived closest to the power lines, and it spurred calls to action by the Swedish government. The problem with the conclusion, however, was that the number of potential ailments, i.e., over 800, was so large that it created a high probability that at least one ailment would exhibit the appearance of a statistically significant difference by chance alone, a situation known as the multiple comparisons problem. Subsequent studies failed to show any association between power lines and childhood leukemia.
Dog Whistle #
In politics, a dog whistle is the use of coded or suggestive language in political messaging to garner support from a particular group without provoking opposition.
Quoting Out Of Context #
Quoting out of context (sometimes referred to as contextomy or quote mining) is an informal fallacy in which a passage is removed from its surrounding matter in such a way as to distort its intended meaning. […] One of the most familiar examples of contextomy is the ubiquitous “review blurb” in advertising. The lure of media exposure associated with being “blurbed” by a major studio may encourage some critics to write positive reviews of mediocre movies. However, even when a review is negative overall, studios have few reservations about excerpting it in a way that misrepresents the critic’s opinion.
Occam’s Razor #
" The simplest explanation is usually the right one "
- William of Ockham, but not really?
Okay, so technically, this is a misquote. See the Wikipedia article: Occam’s Razor (Wikipedia) for more information on this. Regardless, this is what everybody means when they talk about Occam’s Razor
There’s a bit of a problem: “simplest” here is a bit crude. Does it mean simplest to describe or simplest to justify? For example, saying ‘God created the universe’ is very easily described, but to justify requires the proof that a supreme being exists, that it’s a singular supreme being, and if you mean the Christian God, that it’s that God specifically, then that that being didn’t exist prior to the universe. You get the idea.
If the question is more mundane, like “where is my phone?” the answer of ‘in your pocket’ is both much easier to describe and much easier to justify than ‘In the 5th dimension which may only be entered by accidental entry from between the couch cushions on the eve of a solstice’.
Basically, while you can’t rule out complex answers entirely, if there’s an unknown you should assume the simplest answer.
Tragedy of the commons #
The tragedy of the commons is a situation in a shared-resource system where individual users, acting independently according to their own self-interest, behave contrary to the common good of all users by depleting or spoiling the shared resource through their collective action.
The easiest way to see this is to talk about an example, so let’s assume the case of two criminals, arrested by the police and some weird judicial system where the following is possible:
The police don’t have enough evidence to get a large sentence on either perp, if neither fesses up, each gets 2 years in prison. But, they have an idea, they offer either of the criminals to only serve 1 year if they rat out the other, and then the other serves 10 years. If they both rat out each other, then both serve 10 years. Both criminals are given the same offer, but neither is given a chance to coordinate. Each of them, acting in their own self interest, would only have to serve 1 year, but if both do, each has to serve 10. If they chose to rat each other out, that’s an example of the tragedy of the commons.
This scales up too, everything from CO2 emissions causing climate change to vaccines can be seen as cases of this.
Vaccines do have some side effects, usually just a low fever and a sore arm, and very rarely something serious. It’s just that by having a high enough population vaccinated we can be safe from much much more likely threats like polio. Vaccinate your fucking kids, Karen. Don’t contribute to the tragedy of the commons.
Self-censorship is the act of censoring or classifying one’s own discourse. This is done out of fear of, or deference to, the sensibilities or preferences (actual or perceived) of others and without overt pressure from any specific party or institution of authority. Self-censorship is often practiced by film producers, film directors, publishers, news anchors, journalists, musicians, and other kinds of authors including individuals who use social media.
In authoritarian countries, creators of artworks may remove material that their government might find controversial for fear of sanction by their governments. In pluralistic capitalist countries, repressive judicial lawmaking can also cause widespread “rivercrabbing” of Western media.
Identity Politics: #
Doomscrolling is the act of consuming a large quantity of negative online news, typically without pause, to the detriment of the mental health of the person consuming it. Essentially, if the news is bad or depressing, one can ‘doomscroll’ it.
Chilling Effect #
In a legal context, a chilling effect is the inhibition or discouragement of the legitimate exercise of natural and legal rights by the threat of legal sanction.
A lawsuit initiated specifically for the purpose of creating a chilling effect may be called a Strategic Lawsuit Against Public Participation (“SLAPP”).
Streisand Effect #
The Streisand effect is a social phenomenon that occurs when an attempt to hide, remove, or censor information has the unintended consequence of further publicizing that information, often via the Internet.
Creeping Normality and the Overton Window #
Creeping normality (also called gradualism, or landscape amnesia) is a process by which a major change can be accepted as normal and acceptable if it happens slowly through small, often unnoticeable, increments of change. The change could otherwise be regarded as objectionable if it took place in a single step or short period.
The Overton window is the range of policies politically acceptable to the mainstream population at a given time. It is also known as the window of discourse. The term is named after Joseph P. Overton, who stated that an idea’s political viability depends mainly on whether it falls within this range, rather than on politicians' individual preferences.
Hanlon’s Razor #
" Never attribute to malice that which is adequately explained by stupidity "
- Robert J. Hanlon
Dunning-Kruger Effect #
The Dunning–Kruger effect is a cognitive bias in which people with low ability at a task overestimate their ability. It is related to the cognitive bias of illusory superiority and comes from people’s inability to recognize their lack of ability.
Basically, some people assume they know things when they really don’t.
The Ship of Theseus #
In the metaphysics of identity, the ship of Theseus is a thought experiment that raises the question of whether an object that has had all of its components replaced remains fundamentally the same object.
Think of The Children #
There is a whole class of fallacies in this group, as appeals to emotions like fear, flattery, being part of the in group, loyalty, etc. Covering all of them seems a bit excessive, so instead, just know to look out for any appeals to emotion that attempt to stand in for actual evidence.
“Think of the children” (also “What about the children?") is a cliché that evolved into a rhetorical tactic. Literally, it refers to children’s rights (as in discussions of child labor). In debate, however, it is a plea for pity that is used as an appeal to emotion, and therefore it becomes a logical fallacy.
Basically, people might use protecting children an an excuse to ban all porn or some other extreme measure under the assumption that if you try to disagree with their view you’ll look awful because you’re not thinking of the children.
Schrodinger’s Douchebag #
Other Resources #
Logicalfallacies.org covers many of these same fallacies, plus a few I didn’t touch on, and is hugely better written. Give it a look