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92 Cards in this Set
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Regular Ad Hominem
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1. A makes claim B;
2. there is something objectionable about A, 3. therefore claim B is false. It must be clear that the purpose of the characterization is to discredit the person offering the argument, and, specifically, to invite others to discount his arguments. In the past, the term ad hominem was sometimes used more literally, to describe an argument that was based on an individual, or to describe any personal attack. |
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Inverted Ad Hominem
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1. A makes claim B;
2. there is something desirable about A, 3. therefore claim B is true. |
aka appeal to authority
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Ad hominem abusive, argumentum ad personam
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Example 1: "Jack is wrong when he says there is no God because he is a convicted felon."
Example 2: Person A: "There is a God and archaeological records of the Middle East prove it." Person B: "Well, that's what I'd expect a fundamentalist Christian to say." |
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Ad hominem circumstantial
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Example: "Tobacco company representatives are wrong when they say smoking doesn't seriously affect your health, because they're just defending their own multi-million-dollar financial interests."
Not irrational, but not correct in logic, either. |
Mandy Rice-Davies
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Ad hominem tu quoque
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Example 1: "You say airplanes are able to fly because of the laws of physics, but this is false because earlier you said airplanes fly because of magic."
Example 2: "You cannot accuse me of libel because what you do is libel as well." |
Often a specific kind of the two wrongs make a right fallacy
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Genetic fallacy*
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When the origin of a belief, claim, or theory is confused with its justification. This fallacy is more often used to discredit a belief, though it may also be used to support one.
Example 1: "The Nazis were the first to practice eugenics. So it must be a bad idea." Example 2: "You only believe in God because your parents taught you to. So your belief must be false. (Correct form would be: You believe in God because your parents taught you to; you believe in your parents; therefore your belief in God is indirect.)" |
Related to reliabilism and appeal to authority and includes ad hominem, argumentum ad verecundiam and the bandwagon fallacy. Related to red herring and slippery slope also.
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Valid Ad Hominem
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1. A committed perjury when he said Q
2. We should not accept testimony for which perjury was committed 3. therefore, A 's testimony for Q should be rejected |
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Amphibology, amphiboly
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Teenagers shouldn't be allowed to drive. It's getting too dangerous on the streets.
From the above could be interpreted that teenagers shouldn't drive because they will be in danger, or that they shouldn't drive as they are causing all the danger. Dog for sale. Will eat anything. Especially fond of children. At our drugstore, we dispense with accuracy! (Professor to student, on receiving a fifty-page term paper): "I shall waste no time reading it." |
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Appeal to authority, argument from authority, argumentum ad verecundiam
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* Referring to the philosophical beliefs of Aristotle. "If Aristotle said it was so, it is so".
* Quotes from religious books such as the Bible. "The Bible says X, therefore X is the right thing". * Claiming that some crime is morally wrong because it is illegal. "It's against the law for stores to be open on weekends, therefore it's wrong for them to do so". * Referencing scientific research published in a peer reviewed journal. "Science (in the form of an article in a prestigious journal) says X, therefore X is so". * Believing what one is told by one's teacher. "My teacher said so, therefore it must be right." Only sometimes is an appeal to authority a logical fallacy, such as seen in marketing campaigns (Arthur C. Clarke promoting dental floss, etc.). Must meet conditions. |
Related to bandwagon fallacy
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Appeal to belief, appeal to the majority, argumentum ad populum
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1. Most people believe in some sort of God, so it must be true.
2. Most Americans hold that the Vietnam War was morally wrong. Therefore, the Vietnam War was morally wrong. 3. Southern segregationists didn't see anything wrong with what they were doing. Therefore, it must not have been wrong. (or: Therefore, it wasn't wrong to them.) 4. Throughout history, most people have believed in some sort of God. Therefore, you should also believe in God. Not a fallacy when considered as parts of social ettiquette and democratic processes. |
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Appeal to consequences, argumentum ad consequentiam
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* "You cannot believe that water companies should belong to the public. Think of all the utility shares our family owns!".
* "God must exist: so many people find happiness in religion." * "God must not exist: religious people still act badly." |
Related to argumentum ad baculum
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Appeal to emotion: appeal to fear, argumentum ad metum, argumentum in terrorem
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* "We must raise taxes or else even more hospitals will be closed"
* "You should stop drinking unless you want to die young like your father." * "If you don't graduate from high school you'll always be poor." * "The suspension of certain civil liberties is a necessary measure to combat terrorism" * "If we allow immigrants to move into our country they'll rob us of our jobs/drain our welfare system" |
Related to red herring and false dilemma fallacy
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Appeal to emotion: appeal to flattery
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"Surely a man as smart as you can see this is a brilliant proposal."
"I needed a beautiful woman to endorse my product, so naturally I thought of you." |
Related to red herring
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Appeal to emotion: appeal to pity, argumentum ad misericordiam
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* "I hope you like my proposal. It took me six years to write and I don't know what I'd do if you reject it."
* "Look at that poor homeless kitty. I bet it hasn't eaten in days. You should adopt it." |
Related to red herring
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Appeal to emotion: appeal to ridicule
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* If Einstein is right that would mean that when I drive my car it gets shorter and heavier. That's crazy!
* You can't have a cat called Fido. Calling a cat Fido would just be silly! |
Related to red herring
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Appeal to emotion: appeal to spite, argumentum ad odium
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* "By voting for my proposal instead of Jim's, you'll finally have a chance to get back at him for running over your dog!"
* "Bill Gates dumped you back in highschool. Therefore you should never buy any Microsoft products." |
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Appeal to emotion: wishful thinking
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* Economist Irving Fisher said that "stock prices have reached what looks like a permanently high plateau" a few weeks before Black Thursday in 1929, which helped to trigger the Great Depression.
* President John F. Kennedy believed that, if overpowered by Cuban forces, the CIA-backed rebels could "escape destruction by melting into the countryside" in the Bay of Pigs fiasco. * Paul Wolfowitz predicted "an explosion of joy will greet our soldiers" in the run-up to the 2003 Iraq War. |
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Appeal to motive
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* "That website recommended nVidia's graphics chip over ATI's. But they also display nVidia advertising on their site, so they were probably biased in their review." The thesis in this case is the website's evaluation of the relative merits of the two chips.
* "The only reason why she got the part in that movie is because her husband is the director." In this case, the thesis is less clear, but could be an assertion that the husband made in regard to his wife's acting ability. * "The referee comes from the same place as (a sports team), so his refereeing was obviously biased towards them." In this case, the thesis consists of the referee's rulings. A common occurrence in appeals to motive is that only the possibility of a motive (however small) is shown, without showing the motive actually existed. Indeed, it is often assumed that the mere possibility of motive is evidence enough. |
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Appeal to novelty, argumentum ad novitam
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* "Hovercars are the wave of the future! You should invest all your money in Hovercar stocks." (Hovercars may be futuristic, but that does not necessarily make them a sound financial investment.)
* "This computer was made in 2003, therefore it is far superior to that computer made in 2001." (Although computer speed is increasing, one should consider actual specifications rather than mere date-of-construction.) The so-called "Dot-com bust" of the early 2000s could easily be interpreted as a sign of the dangers of naïvely embracing new ideas without first viewing them with a critical eye. |
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Appeal to probability
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* "There are many hackers that use the internet. Therefore, if you use the internet without a firewall, it is inevitable that you will be hacked sooner or later."
* "AMD has been catching up to Intel in recent years. In a few years they will definitely take over Intel's position, and eventually put them out of business altogether." * "When soccer becomes popular in a town, hooliganism will become a major problem. Thus, if we allow a soccer team in our town, we will be overrun by hooligans." (also a False cause fallacy) |
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Appeal to tradition, appeal to common practice, argumentum ad antiquitam
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* "Our society has always ridden horses. It would be foolish to start driving cars." (rebuttal: we want to travel further and horses are no longer adequate for traveling such great distances)
* "Your invention is a bad idea because it has no historical precedent." (rebuttal: the fact that something has not been previously attempted does not guarantee it will ultimately fail) * "These rules were written 100 years ago and we have always followed them. Therefore, there is no need to change them." (rebuttal: the society in which the rules were written have changed, and thus are no longer applicable) |
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Argument from fallacy, argumentum ad logicam, fallacy fallacy
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"When I let go of this pencil, Angels from Heaven on high will push it downward. Therefore, it will accelerate towards the ground at 9.80665 meters per second per second."
Now, even if you could disprove that angels will exert downward pressure on your pencil, it would not follow that if you let go of the pencil then it would not fall to the ground. It just means that "angel theory" is not a sound way of reaching that conclusion, regardless of the conclusion's truth or falsity. |
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Argument from ignorance, argumentum ad ignorantium, argument by lack of imagination
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* I find it hard to imagine a way in which a thousand-ton piece of metal could fly through the air. Therefore, airplanes will never work.
* This city can't handle public transportation because we don't have room for any train tracks. (the speaker fails to consider alternative forms of public transportation, such as buses, as well as the city's ability to appropriate land) * I cannot imagine any ways for artists and inventors to earn a living without intellectual property laws * Therefore such methods cannot exist * Therefore intellectual property laws are necessary * The evolutionary purpose served by camouflage is protection from predators. * Polar bears have no predators. * Therefore, camouflage serves no evolutionary purpose in polar bears. * Polar bears have camouflage. * Therefore, some attributes exist in nature which exhibit no evolutionary purpose. * Therefore, the theory of evolution does not account for some observable facts in nature. |
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Argument from silence, argumentum e(x) silentio
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John: Do you know your wife's email password?
Jack: Yes, I do as a matter of fact. John: What is it? Jack: Hey, that's none of your business. If Jack continues to refuse to give John the password, John cannot reasonably conclude that he does not in fact know it. In other words, his ignorance is not the most plausible explanation for his silence In some legislative systems juries are explicitly instructed not to infer anything because of an accused silence, the right to silence. For example if an accused said that he was giving a lecture in Spanish at the time a crime was committed, but refused to speak any Spanish, the jury should not conclude that he couldn't speak Spanish and the alibi is false. This in effect bars the use of argument from silence. |
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Argumentum ad baculum, appeal to force
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Many young people in the United States who opposed the Vietnam War were told that they should not hold such a view, because they would face discrimination from potential employers.
A similar fallacy is the claim that one should believe in the validity of the Bible lest God strike you down! |
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Argumentum ad crumenam
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Example:
If you're so smart, why aren't you rich? I think Mary is a good role model. She's pretty rich so she must be doing something right. |
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Argumentum ad lazarum
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Example:
Hermits are wise, they are not distracted by possessions. |
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Argumentum ad nauseam, argument from repetition
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This logical fallacy is commonly used as a form of rhetoric by politicians, and it is one of the mechanisms of reinforcing urban legends. In its extreme form, it can also be a form of brainwashing. Though a logical fallacy, nonetheless it is convincing to people because, as one of history's main practitioners of this propaganda technique, Joseph Goebbels, observed, if something is repeated as true often enough, people will eventually come to believe it is true.
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Argumentum ad numerum, argument from numbers
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* Using a poll to justifiy the claims - Since 88% of the people polled believed in UFOs they must be true.
* Direct appeal to numbers - A vast majority of people thinks God exists, therefore he does. |
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Base rate fallacy, base rate neglect
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In some experiments, students were asked to estimate the Grade Point Averages of hypothetical students. When given relevant statistics about GPA distribution, students tended to ignore them if given descriptive information about the particular student, even if the new descriptive information did not seem to have anything to do with school performance.
This finding has been used to argue that interviews are an unnecessary part of the college admissions process because empirical evidence shows that interviewers are unable to pick successful candidates better than basic statistics. Similarly, economists argue that stock market brokers commit this mistake because market performance and the performance of any individual stock are indistinguishable from chance movement, and professionally-chosen portfolios do no better than those composed of stocks picked at random. |
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Bandwagon fallacy, appeal to the people, authority of the many, consensus gentium, argument by consensus, appeal to the gallery, appeal to popularity or argumentum ad populum
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* One could claim that smoking is a healthy pastime, since millions of people do it. However, knowing the dangers of smoking, we instead say that smoking is not a healthy pastime despite the fact that millions do it.
* One could claim that 13 is an unlucky number, since many or all people believe it to be. However, statistically 13 is no more unlucky than any other number. Of course, this only applies to 'something' with an objective criterion, such as the health effects of smoking. |
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Begging the question, petitio principii
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* Suppose Paul is not lying when he speaks.
* Paul is speaking. * Therefore, Paul is telling the truth. |
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Conjunction fallacy
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Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.
Which is more likely? 1. Linda is a bank teller. 2. Linda is a bank teller and is active in the feminist movement. 85% of those asked chose option 2. However, mathematically, the probability of two events occurring together (in "conjunction") will always be less than or equal to the probability of either one occurring alone. |
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Correlative based fallacies, fallacies of distraction: Fallacy of many questions, complex question, loaded question, or plurium interrogationum
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It is committed when someone asks a question that presupposes something that has not been proven or accepted upon by the people involved--i.e., a premise is included which is at least as dubious as the proposed conclusion.
The standard example of this is the question Have you stopped beating your wife? Whether the person asked answers yes or no, he will admit to having beaten his wife at some time in the past. Thus, that fact is presupposed by the question, and if it has not been agreed upon by the speakers before, the question is improper, and the fallacy of many questions has been committed. |
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Correlative based fallacies, fallacies of distraction: False dilemma, fallacy of the excluded middle, false dichotomy, either/or dilemma or bifurcation
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Either creationism must be true or Darwin's theory of evolution must be true. Therefore, if it is shown that Darwin's theory is false, then creationism must be true.
Will you re-elect Lyndon Johnson, or face nuclear holocaust? Are you with us, or with the terrorists? Either you go to college, or you will wind up flipping hamburgers for a living. |
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Correlative based fallacies, fallacies of distraction: Denying the correlative
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You say that you have shown that my client must have stolen the money, because no-one else had the opportunity to do so. But what if the money never existed?
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Correlative based fallacies, fallacies of distraction: Suppressed correlative
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Anne: "OK, I can prove that Ants are not small. To Bacteria they are large".
Bill: "OK, so Bacteria are small!". Anne: "No, because to a virus they are large. Everything is large to something, so nothing is really small!" * Well, I would give money to the poor, but I believe that the world is so wonderful and rich that nobody can really be poor. * All dogs are black when it is dark. Therefore, Lassie is a black dog. |
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Dicto simpliciter ad dictum secundum quid, Accident, destroying the exception
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1. Cars should never exceed the speed limit
2. Police cars are cars 3. Therefore, police cars should never exceed the speed limit 1. Cutting people with a knife is a crime. 2. Surgeons cut people with knives. 3. Surgeons are criminals. This fallacy may occur when we confuse generalizations ("some") for categorical statements ("always and everywhere"). It may be encouraged when no qualifying words like "some", "many", "rarely" etc. are used to mark the generalization. For example: Jews killed Jesus The premise above could be used in an argument concluding that all Jews or current Jews should be responsible for Jesus' death. Qualifying the first term: Some Jews killed Jesus |
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A dicto secundum quid ad dictum simpliciter, Converse accident
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If we allow people with glaucoma to use medical marijuana then everyone should be allowed to use marijuana.
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Equivocation
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A feather is light.
What is light cannot be dark. So a feather cannot be dark. |
Related to fallacy of four terms
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False analogy
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The universe is like an intricate watch.
A watch must have been designed by a watchmaker. Therefore, the universe must have been designed by some kind of creator. |
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False premise
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* Killing exists as a component of human behavior. (premise)
* Killing is insane. (false premise) * Therefore insanity is established in people who kill. (conclusion) |
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False compromise
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* Rush Limbaugh says there's no proof that global warming is happening. Radical environmentalists say the proof is clear-cut. The truth must lie somewhere in between.
* Bob is moving to a new city in order to take a job. If he gets an apartment in the city center, it will be too expensive for him to afford a car, but he will be able to walk to work and most things he needs. On the other hand, Bob could move to the country, where he could afford a car which he could drive into the city for work and services, but he will spend a great deal of time commuting. Unable to decide between the two alternatives, Bob compromises by moving to the suburbs, where it is too expensive to own a car, but where nothing is within walking distance. * Jim wants to go north, Fred wants to go south. West or east must be the right choice. * An organization is deciding where to build its new headquarters. One bloc wants to build it on the east side of the river. Another bloc wants to build it on the west side of the river. There must be some location that will make both blocs happy. |
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Fallacy of distribution: fallacy of composition
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"This fragment of metal cannot be broken with a hammer, therefore the machine of which it is a part cannot be broken with a hammer." This is clearly fallacious, because many machines can be broken into their constituent parts without any of those parts being so breakable.
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Fallacy of distribution: fallacy of division
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For example, if from the fact that a Boeing 747 can fly unaided across the ocean I infer that one of its jet engines can fly unaided across the ocean, I am guilty of the fallacy of division.
An application: Famously and controversially, in the philosophy of the Greek Anaxagoras (at least as it is discussed by the Roman Atomist Lucretius), it was assumed that the atoms constituting a substance must themselves have the salient observed properties of that substance: so atoms of water would be wet, atoms of iron would be hard, atoms of wool would be soft, etc. This doctrine is called homeomeria, and it plainly depends on the fallacy of division. |
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Ecological fallacy
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Example 1. A study is done that shows people from Springfield score higher on the SATs, on average, than people from North Haverbrook. Assuming that a randomly selected individual from Springfield scored higher on the SATs than a randomly selected individual from North Haverbrook is an ecological fallacy. Since the SAT scores given in the study were an average, it is indeed possible that the individual from Springfield scored in the bottom ten percent on the SATs and the individual from North Haverbrook just happened to score in the top 10%.
Example 2. Imagine two communities, Chiptown and Pittsville. Within each community there is a typical divide between the rich and poor, the rich living in gated communities on the hills and the poor living adjacent to the industrial districts that pump carcinogens into their backyards. In both communities, the poor people have a cancer incidence that is many times that of the wealthy people. In Chiptown, where the dominant industry is high-tech computer manufacturing, the overall salaries are higher for both rich and poor people, but the carcinogens spewed into the environment are particularly nasty, giving cancer to nearly all those exposed (poor people). Prof. Newbie comes along and decides to examine the risk factors for cancer. He looks up the cancer rates and median incomes of these two towns on the CDC and U.S. Census webpages. He finds, to everyone's surprise, that the cancer incidence is higher in the wealthier community. He concludes that higher income is a risk factor for cancer. In fact, we know that exactly the opposite is true. In fact, in the wealthier community of Chiptown, being poor is especially dangerous to one's health. |
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Faulty generalization: biased sample
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1. I wouldn't like to go to America because the of all the gun crime, we see it on the news all the time.
2. Doctor: "Why don't patients make some effort to look after themselves? My surgery is full of people who eat, drink, smoke and don't get any exercise". Of course she may have many more patients who do look after themselves and don't often turn up in her surgery. 3. Why do young people all take drugs and go around mugging old ladies? You read about it in the paper all the time! 4. Child "When I grow up I want to be a singer. Have you seen how much money those pop-stars make?!" |
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Faulty generalization: hasty generalization
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* "I loved the hit song, therefore I'll love the album it's on."
* "This Web site looks OK to me on my computer; therefore, it will look OK on your computer, too." * "In my lifetime, there has been a leap year every fourth year; therefore, every fourth year, past, present, and future, is a leap year." * "My dog is black. Therefore, all dogs must be black." |
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Faulty generalization: overwhelming exception
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* All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? (The attempted implication (fallaciously false in this case) is that the Romans did nothing for us). This is a quotation from Monty Python's Life of Brian.
* Our foreign policy has always helped other countries, except of course when it is against our National Interest... (The false implication is that our foreign policy always helps other countries). * All Americans are useless at foreign languages. Ok, I'll make an exception for those who live in multi-ethnic neighbourhoods, have parents who speak a foreign language, are naturally gifted in languages, have lived abroad or who went to a school with a good foreign language program, but the rest are absolutely useless at foreign languages. * All dogs are black, except for those which are other colours. (this is also a tautology) |
similar to a hasty generalization
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Faulty generalization: Statistical special pleading
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* Studies have shown that 5% of patients with foobar disease die within a year. We have shown that when patients are treated with supermed, only 3% of those aged 60 or younger die within a year. Therefore supermed is an effective treatment.
* A study of teen-age gang members has shown that 40% of those who are atheists have been convicted of a violent offence. This is hundreds of times the number of people in the general population who are convicted of such offences. This clearly shows that atheism leads to violence. |
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Faulty generalization: misleading vividness
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Anne: "I am giving up extreme sports now that I have children. I think I will take up golf".
Bill: "I wouldn't do that. Do you remember Charles? He was playing golf when he got hit by a golf-cart. It broke his leg, and he fell over, giving himself a concussion. He was in hospital for a week and still walks with a limp. I would stick to paragliding!" Bill: "Police marksmen should use tasers instead of guns when it's safe to do so.". Anne: "Can you imagine what would happen if those darts from the taser went into your eyes, piercing your eyeballs, and then if they sent the high voltage through your eyes and brain! It would probably kill you and be much worse than being shot." |
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Ignoratio elenchi, irrelevant conclusion
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* Defense Lawyer: "Tax fraud is not much of a crime, and it is unfair for my client to be subjected to this lengthy and stressful trial over such a minor offense." (This is irrelevant, the lawyer's job is to prove innocence.)
* There is a lot of violence in America's inner-cities. You should therefore support an increase to welfare funding. (One can agree with either of these statements without agreeing to the other. There is no proof one is relevant to the other.) * Baseball player Mark McGwire just retired. Clearly, he deserves to be in the Hall of Fame. After all, he's such a nice guy, and he gives a lot of money to all sorts of charities. (Charisma and charity are not qualifications for induction into the Hall of Fame, therefore they do not support the conclusion.) * The premier's tax policies may be popular, but I suspect he had an affair and is paying the woman to keep quiet. The media should investigate that! (This is an example of a red herring, as the speaker attempts to distract from tax policy with the unrelated matter of the alleged affair.) When this logical fallacy is used in an attempt to intentionally confuse or distract someone else, it is known as a "red herring". |
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If-by-whiskey
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"If by whiskey, you mean the water of life that cheers men's souls, that smooths out the tensions of the day, that gives gentle perspective to one's view of life, then put my name on the list of the fervent wets.
"But if by whiskey, you mean the devil's brew that rends families, destroys careers and ruins one's ability to work, then count me in the ranks of the dries." |
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Homunculus fallacy
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This fallacy accounts for a phenomenon in terms of the very phenomenon that it is supposed to explain.
"According to the legend, whenever an agent does anything intelligently, his act is preceded and steered by another internal act of considering a regulative proposition appropriate to his practical problem." "Must we then say that for the ..[agent's].. reflections how to act to be intelligent he must first reflect how best to reflect how to act? The endlessness of this implied regress shows that the application of the appropriateness does not entail the occurrence of a process of considering this criterion." |
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Historian's fallacy
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* Julius Caesar should not have seized power, because he would only be assassinated.
* World War I should not have been fought, because it accomplished nothing and led only to World War II. * Neville Chamberlain should not have attempted to deal with Adolf Hitler through diplomacy, since Hitler's ambitions would not stop and would lead to World War II. * It was a mistake for the United States to arm the mujahadeen in Afghanistan to fight the Soviet Union, because some of the mujahadeen would engage in terrorism against the United States twenty years later. |
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Honor by association
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1. George W. Bush will make a good president, because his father was a good president.
2. Alice is a lawyer, and Alice thinks highly of Bob. Therefore, Bob must know the law. |
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Guilt by association, bad company fallacy
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* Atheism must be wrong — Karl Marx and Stalin were atheists, and just look at them.
* Osama bin Laden is a Muslim, so Islam is an evil religion. * Catholic priests molest children, so Catholicism is evil. |
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Gambler's fallacy
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* A random event is more likely to occur because it has not happened for a period of time;
* A random event is less likely to occur because it has not happened for a period of time; * A random event is more likely to occur because it recently happened; and * A random event is less likely to occur because it recently happened. When flying on an airplane, a man decides to always bring a bomb with him. "The chances of an airplane having a bomb on it are very small," he reasons, "and certainly the chances of having two are almost none!" |
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Inverse gambler's fallacy
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You see a pair of fair dice rolled once, and the result is double-sixes. This is a quite improbable result, so you conclude that the dice were probably rolled many times before.
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Correlation implies causation
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Teenage boys eat lots of chocolate.
Teenage boys have acne. Therefore, chocolate causes acne. Ice-cream sales are strongly (and robustly) correlated with crime rates. Therefore, ice-cream causes crime. Gun ownership is correlated with crime. Therefore, gun ownership leads to crime. |
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Meaningless statement
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# A statement in argumentation may be considered meaningless because it draws a distinction without a difference, that is, asserts that two categories are disjoint without proposing a way to distinguish among them. For instance, the claim, "Pornography is different from erotica, but not in any particular way I can explain," may be considered to draw a distinction that makes no difference.
# "An orange is an apple which has many idiosyncratic features such as color, texture, taste, internal structure and chemical composition." # "I am wearing clothes made of totally unobservable fibers." |
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Middle ground, argumentum ad temperantiam
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The middle ground (also called argumentum ad temperantiam) between extreme points of view is often described as the logical place to find truth. This is a logical fallacy. The middle ground is most often invoked when there are sharply contrasting views which are deeply entrenched.
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Naturalistic fallacy
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Many people use the phrase "naturalistic fallacy" to characterize inferences of the form "This behavior is natural; therefore, this behavior is morally acceptable" or "This behavior is unnatural; therefore, this behavior is morally unacceptable".
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Negative proof
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"No one has produced an example of one; therefore it doesn't exist."
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Non sequitur: affirming the consequent
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1. If A then B. (e.g. If I am a cat, I am a mammal.)
2. B. (e.g. I am a mammal.) 3. Therefore, A. (Therefore, I am a cat.) |
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Non sequitur: denying the antecedent
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1. If A then B. (e.g. If I am in Tokyo, I am in Japan.)
2. Not A. (e.g. I am not in Tokyo.) 3. Therefore, not B. (e.g. Therefore, I am not in Japan.) |
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No true Scotsman
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Argument: "No Scotsman puts sugar on his porridge."
Reply: "But my uncle Angus likes sugar with his porridge." Rebuttal: "Ah yes, but no true Scotsman puts sugar on his porridge." |
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Package-deal fallacy
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My opponent is a conservative who voted against higher taxes and welfare, therefore he will also oppose gun control and abortion." (Usually the connection is made much more implicitly.)
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Pathetic fallacy
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# "Rwanda wants to punish the Congo!"
# "Ah, it is no good. That car just refuses to start!" # "the moving object, due to its mass, wants to keep going" # "Being heavier than air, water wants to go down more than air does, so it makes the air go up" # "X flies up to Y because positive and negative charges like one another" # "Iron likes a magnet" # "Nature abhors a vacuum" |
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Perfect solution fallacy
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This "terrorist safety net" is a bad idea. Terrorists will still be able to get through!
Yes, some terrorists would still be able to get through, but would it be worth stopping those terrorists that it would stop? These anti-drunk driving ad campaigns are not going to work. People are still going to drink and drive no matter what. It may not eliminate 100% of drunk driving, but is the amount by which it would reduce the total amount of drunk driving enough to make the policy worthwhile? |
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Poisoning the well
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Before you listen to my opponent, may I remind you that he has been in jail.
Don't listen to what he says, he's a lawyer. |
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Questionable cause, causal fallacies, non causa pro causa, false cause: Correlation implies causation, cum hoc ergo propter hoc
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Teenage boys eat lots of chocolate.
Teenage boys have acne. Therefore, chocolate causes acne. Ice-cream sales are strongly (and robustly) correlated with crime rates. Therefore, ice-cream causes crime. Gun ownership is correlated with crime. Therefore, gun ownership leads to crime. |
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Questionable cause, causal fallacies, non causa pro causa, false cause: fallacy of the single cause, joint effect, causal oversimplification
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For instance, after a school shooting, editorialists debate whether it was caused by the shooter's parents, TV violence, our culture, stress on students, Hollywood or the accessibility of guns. In fact many different causes including some of those may all have necessarily contributed.
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Questionable cause, causal fallacies, non causa pro causa, false cause: Joint effect
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At the root of this fallacy is that ice cream consumption and murder rates are highly correlated. Now, does ice cream incite murder or does murder increase the demand for ice cream? Neither: they are joint effects of a common cause, namely, hot weather during the summer season.
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Questionable cause, causal fallacies, non causa pro causa, false cause: Post hoc ergo propter hoc, post hoc, coincidental correlation
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* If event A causes event B, then A must have occurred before B.
* Event A occurred before event B. * Therefore, A must have caused B. For example, if a person sees a coin on the ground and picks it up, and later receives good news, that person may become convinced that finding the coin resulted in the good news, even though it was a mere coincidence. |
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Questionable cause, causal fallacies, non causa pro causa, false cause: Regression fallacy
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When his pain had gotten worse, he went to a witchdoctor, after which it subsided a little. Clearly, he benefitted from the witchdoctor's powers.
After the new President was elected, the country had far fewer terrorist attacks. The citizens applauded this bold initiative. The student did exceptionally poorly last semester, so I punished him. He did much better this semester. Clearly, punishment is effective in improving student's grades. -Towards the mean |
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Questionable cause, causal fallacies, non causa pro causa, false cause: Texas sharpshooter fallacy
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* Attempts to find cryptograms in the works of William Shakespeare, which tended to report results only for those passages of Shakespeare for which the proposed decoding algorithm produced an intelligible result.
* The roulette ball has landed on odd numbers eight times in a row now... there must be something wrong with it. (The belief that after eight odd numbers in a row the ball is more likely to land on an even number is an example of gambler's fallacy.) * More children in town A have leukemia than in town B. Therefore, there must be something wrong with town A. (If that fact is linked to another one, it may be an example of cum hoc ergo propter hoc or post hoc ergo propter hoc.) |
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Questionable cause, causal fallacies, non causa pro causa, false cause: Wrong direction
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For instance, a tobacco company executive once suggested that cancer caused smoking as a matter of pain relief, to explain the high correlation between them
Children that watch a lot of TV are the most violent. Clearly, TV makes children more violent. |
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Reification, hypostatisation
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* "That country doesn't have any democracy. We should give some of ours to them".
* "Just because we don't have any music, dance, paintings, drawings, or drama in this city doesn't mean we're devoid of art". -treating an abstract concept as if it were a real, concrete thing |
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Relativist fallacy, subjectivist fallacy
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A logical fallacy committed, roughly speaking, when one person claims that something may be true for one person but not true for someone else.
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Retrospective determinism
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When he declared himself dictator of the Roman Republic, Julius Caesar was bound to be assassinated sooner or later.
Caesar was assassinated when he declared himself dictator. Sic semper tyrannis: this just goes to show you that all dictators will eventually be overthrown by the people. |
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Slippery slope
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* If we allow women to abort their unborn children, then soon no life will be held sacred.
* If we forbid partial-birth abortion, soon all abortion will become illegal. * If we allow gun registration, then gun confiscation will follow. * Use of 'soft' drugs such as cannabis will inevitably lead to addiction to 'harder' drugs such as heroin. * If we allow gay marriage, people will soon want to marry children and animals as well. |
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Special pleading
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* Sure, my client may have stolen, but he is poor, therefore it is excusable.
* You may disagree with my tax plan, but I've taken many more economic classes than you so you should give me the benefit of the doubt. |
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Straw man
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1. Present only a portion of the opponent's arguments (often a weak one), refute it, and pretend that all of their arguments have been refuted.
2. Present the opponent's argument in weakened form, refute it, and pretend that the original has been refuted. 3. Present a misrepresentation of the opponent's position, refute it, and pretend that the opponent's actual position has been refuted. 4. Present someone who defends a position poorly as the defender, refute their arguments, and pretend that every argument for that position has been refuted. 5. Invent a fictitious persona with actions or beliefs that are criticised, and pretend that the person represents a group that the speaker is critical of. |
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Style over substance fallacy
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* Person 1: Who needs a smoke detector? No-one ever has a fire in their house, smoke detectors are a waste of money!
* Person 2: What?! You'd rather save a bit of money than ensure your family's safety? Don't you care whether they burn to death, you f***ing idiot? * Person 1: I don't have to take your insults! Go away! * Person 1: This website says that cars made by Ford do more miles to the gallon than cars made by Vauxhall. * Person 2: That website is amateurish - look at the way it's designed! This other website is much more professional-looking, so it's probably more accurate. |
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Syllogistic fallacy: affirming a disjunct
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Tomorrow it will either rain or the sun will shine.
The weather forecast said it would rain tomorrow. Therefore, the sun will not shine tomorrow. |
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Syllogistic fallacy: affirmative conclusion from a negative premise
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No fish are mammals, and no mammals can fly, therefore all fish can fly.
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Syllogistic fallacy: existential fallacy
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All trespassers will be prosecuted.
Therefore, some of those prosecuted will have trespassed. |
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Syllogistic fallacy: fallacy of exclusive premises
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Since no mammals are fish and some fish are not whales, it follows that some whales are not mammals.
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Syllogistic fallacy: fallacy of the undistributed middle
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All students carry backpacks.
My grandfather carries a backpack. Therefore, my grandfather is a student. |
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Syllogistic fallacy: illicit major
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All dogs are mammals. No cats are dogs. Therefore, no cats are mammals.
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Syllogistic fallacy: illicit minor
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All poodles are mammals. All poodles are pets. Therefore, All pets are mammals.
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