ALPHABETICAL LIST OF INFORMAL LOGICAL FALLACIES
Informal fallacies are arguments that follow valid logical forms but do not lead to conclusions that are necessarily true. The source of their ‘unsoundness’ lies in the argument's content e.g. All politicians are corrupt. Jim is a politician. Therefore, Jim is corrupt. The premise that all politicians are corrupt could be true, but is not necessarily true. Hence, Jim may in fact not be corrupt. The truth of the conclusion is not guaranteed.
Informal fallacies may be subdivided into categories, but these tend to overlap and a specific example may exhibit multiple fallacies or be interpreted in different ways. Also, it is common for one fallacy to have several names.
Some useful categories for study are fallacies of: relevance (intrusion), omission, ambiguity, presumption.
A
abusive fallacy
A subtype of ad hominem when it turns into name-calling rather than arguing about the originally proposed argument.
ad hominem (attacking the person, abusive fallacy, poisoning the well)
Instead of addressing the claims of an argument or position, you attack the person who is making the argument.
e.g. I will not answer your question because you are an idiot.
ambiguous middle term (See equivocation)
A common ambiguity in syllogisms in which the middle term is equivocated.
e.g. Man is the only rational animal. No woman is a man. Therefore, no woman is a rational animal.
amphiboly
Similar to equivocation, but instead of the definition of words being ambiguous, the confusion or deception comes from the structure of the grammar, so that one interpretation may be correct and another one incorrect.
e.g. The government says, ‘Save fuel and waste water.’ So fuel is valuable and water in oversupply.
appeal to authority (argumentum ab auctoritate, argumentum ad verecundiam, irrelevant authority, false attribution)
When someone uses the testimony of an authority in order to warrant their conclusion, but the authority is not an expert in the field in question. Alleged authorities should only be used when the authority is reporting on his or her field of expertise, there is agreement in their field on the issue, and the person can be trusted.
e.g. Matt Damon was seen wearing Ray Ban sunglasses, so they must be the best quality sunglasses.
appeal to common sense (argument from (personal) incredulity)
The argument that a proposition must be false because it contradicts one's personal expectations or beliefs, or is difficult to imagine.
e.g. Common sense tells us that if the earth were a sphere, people on the bottom would fall off.
appeal to consequences (argumentum ad consequentiam)
Where the conclusion is supported by a premise that asserts positive or negative consequences from some course of action in an attempt to distract from the initial discussion.
An argument that concludes an hypothesis (typically a belief) to be either true or false based on whether the premise leads to desirable or undesirable consequences. This may be an attempt to distract from the initial discussion (red herring) or an appeal to emotion — the desirability or not of a premise's consequences does not make the premise true or false. Argumentum ad baculum is a special instance of this form.
appeal to emotion (wishful thinking, appeal to fear, flattery, pity (misericordium), ridicule, spite, envy, hatred, superstition, pride etc.)
A general category of fallacies that use emotion in place of reason to attempt to win the argument. (A type of Red Herring.)
e.g. Roger didn't want to eat his brussel sprouts, but his father told him to think about the starving children in third world countries who had no food at all.
appeal to fear (argumentum ad metum, argumentum in terrorem)
A form of appeal to emotion where a person attempts to create support for an idea by attempting to increase fear towards an alternative. The appeal to fear is common in marketing and politics.
e.g. Quit smoking now or face a greusome death.
appeal to ignorance (argument from ignorance, argumentum ad ignorantium)
The argument that a conclusion must be true (or false), because there is no evidence against (or for) it. Shifts the burden of proof away from the person making the claim.
e.g. Since you haven't proven your innocence, you must be guilty.
e.g. It makes sense to believe in UFOs because no one can prove they don't exist.
appeal to motive
Where a premise is dismissed by calling into question the motives of its proposer. A form of Ad Hominem.
e.g. You claim that my girlfriend is cheating on me only because you want to date her yourself!
appeal to nature (argumentum ad novitam)
Where judgement is based solely on whether the subject of judgement is ‘natural’ or ‘unnatural’.
e.g. Cannabis is healthy because it is natural.
appeal to poverty (argumentum ad lazarum)
Where a conclusion is supported because the arguer is poor. (Opposite of appeal to wealth.)
e.g. The monks have forsworn all material possessions. They must have achieved enlightenment.
appeal to ridicule (reductio ad absurdum)
An argument is made by incorrectly presenting the opponent's argument in a way that makes it appear ridiculous. (A type of red herring or straw man.)
e.g. Evolution? Yes, I believe that my grandparents were monkeys — of course that makes sense.
appeal to tradition (argumentum ad antiquitam)
Where a conclusion is supported solely because it has long been held to be true.
e.g. The earth is flat.
appeal to wealth (argumentum ad crumenam, to the wallet or purse)
Assumes that money is a measure of rightness, and that those with money are more likely to be correct. (Opposite of appeal to poverty.) See appeal to emotion.
e.g. His economic forecast can't be wrong. He is a wealthy man.
appeal to worse problems (fallacy of relative privation, not as bad as fallacy)
Where an argument is dismissed due to what are perceived as more important, but unrelated, problems in the world.
This argument is fallacious when it tends towards ‘nothing matters if it's not literally the worst thing happening’, but there are reasonable uses of this form. Good discussion at rationalwiki.
argument from hidden premises
A hidden premise is a premise that is required in order to reach the stated conclusion, but is not stated clearly in the argument.
e.g. Raw cows' milk is unprocessed. So, everyone should drink it.
The unstated premise is: 'Consuming processed foods is bad for you'.
Having an unstated premis does not necessarily make an argument invalid, or its conclusion unsound. It is however, a device that is often used to deceive or dissemble fallacious reasoning.
argument from the negative
When it is assumed that something is true because the opposite is false. This is valid for binary operations, but most cases in reality have multiple possible resolutions. See false dilemma.
e.g. Summer is not the best season. Therefore, winter must be the best season. (Fails to consider spring and autumn.)
argument from repetition (argumentum ad nauseam)
A proposition that has been repeated so many times that nobody cares to discuss it anymore.
e.g.That movie, “Titanic” deserves the Oscar for best picture. There are other good movies, but not like that one. Others may deserve an honorable mention, but not the Oscar, because “Titanic” deserves the Oscar.
argument from silence (argumentum e silentio)
A fallacy of weak induction that treats the absence of evidence as evidence itself.
e.g. Marco Polo's travel journals don't mention the Great Wall of China, which is evidence that he never visited the country.
argument to moderation (false compromise, middle ground, golden mean fallacy)
Assuming that the compromise between two positions is always correct.
e.g.You say the sky is blue, while I say the sky is red. Therefore, the best solution is to compromise and agree that the sky is purple.
argumentum e contrario (argument from the contrary)
Denotes any proposition that is argued to be correct because it is not disproven by a certain case. It is the opposite of analogy. When analogy is allowed, e contrario is forbidden and vice versa. Arguments e contrario are often used in the legal system as a way to solve problems not currently covered by a certain system of laws. Although it might be used as a logical fallacy, arguments e contrario are not by definition fallacies.
e.g. Law X says that messages can be sent by letter or by telegraph. Therefore, messages cannot be sent by fax machines.
This argument is based on the fact that the law does not mention something (in this case, faxes), but concludes that they must therefore not be used. The belief that lawmakers intentionally excluded fax machines is less reasonable than the assumption that fax machines did not exist at this time and would have been included if the law was drafted today.
argumentum ad baculum (appeal to the stick, appeal to force, appeal to threat)
An argument made through coercion or threats of force to support position. Pointing out the negative consequences of holding the contrary position.
One form: If x accepts P as true, then Q. x acts to prevent Q and succeeds, so Q is not true. Therefore, P is not true.
This form of argument is an informal fallacy, because the attack on Q may not necessarily reveal anything about the truth value of the premise P.
e.g. Believe what I say, or I'll hit you.
argumentum ad invidiam (appeal to envy)
As well as it's specific meaning this term refers to a category of fallacies and rhetorical devices that appeal to undesirable human traits. See appeal to emotion.
e.g. Rich people make their money by ripping off the workers. They should be made to pay higher taxes.
argumentum ad metum (appeal to fear)
An argument that supports a proposition by attempting to generate fear of an alternative. A common tactic in marketing and politics. See appeal to emotion.
Logical form:
Either P or Q is true.
Q is frightening.
Therefore, P is true.
e.g. If you don't believe in God you will go to hell.
argumentum ad populum (appeal to widespread belief, bandwagon argument, appeal to the majority)
Where a proposition is claimed to be true or good solely because many people believe it to be so. A fallacy of relevancey similar to an appeal to authority.
e.g. Nine out of ten dentists recommend Listerine.
argumentum ad speculum See hypothesis contrary to fact.
association fallacy (guilt by association)
When a person, belief or group is attacked or defended on the basis that it has something in common with a positively or negatively viewed person, belief or group. Arguing that because two things share one thing in common, they must share everything in common.
e.g. Baptists are Christian fundamentalism. Roger is a Baptist. Therefore, Roger is a Christian fundamentalist.
B
begging the question (Also called circular reasoning.)
When an argument's premises assume the truth of the conclusion, instead of supporting it.
e.g. We know that the bible is divinely inspired because in the third chapter of II Timothy it says that all scripture is given by divine inspiration of God.
broken window fallacy
An argument which disregards lost opportunity costs (typically non-obvious, difficult to determine or otherwise hidden) associated with destroying property of others, or other ways of externalizing costs onto others.
A ‘fallacy of omission’.
Example: An argument that states breaking a window generates income for a window fitter, but disregards the fact that the money spent on the new window cannot now be spent on groceries.
burden of proof, shifting the See onus probandi.
Where the burden of proof is moved onto the person who denies or questions the assertion being made. The source of the fallacy is the assumption that something is true unless proven otherwise.
e.g. An employee goes to her boss and claims that she has been harassed at work. The boss asks her for evidence to support the claims. She argues that he needs to prove that she wasn't harassed.
C
cherry picking (suppressed evidence, incomplete evidence)
Act of pointing at individual cases or data that seem to confirm a particular position, while ignoring a significant portion of related cases or data that may contradict that position.
e.g. A survey of 50 dentists find that 8 recommend Sensodyne toothpaste. The data is reduced to 10 cases, 8 of which recomment Sensodyne. So the advertisement says: ‘4 out of 5 dentists recommend Sensodyne’.
chronological snobbery (ad annis, ‘to the years’)
Appealing to the age of something as proof or disproof of its truth.
e.g. A survey of 50 dentists find that 8 recommend Sensodyne toothpaste. THe data is reduced to 10 cases, 8 of which recomment Sensodyne. So the advertisement says: ‘4 out of 5 dentists recommend Sensodyne’.
circular reasoning (circulus in demonstrando, assuming the conclusion)
An argument that begins with premises that assume the truth of the conclusion. The argument may be logically valid but the premises are just as much in need of proof as the conclusion.
Logical form: X is true because of Y. Y is true because of X.
Closely related to begging the question, and in modern usage the two generally refer to the same thing.
circular cause and consequence
Where the consequence of the phenomenon is claimed to be its root cause. There are legitimate cause and effect feedback loops. The problem is identifying the root cause.
e.g. The question ‘which came first: the chicken or the egg?’ The problem is that all chickens hatch from eggs and chicken eggs are laid by chickens. The two statements suggest the answer to the question is 1. the egg and 2. the chicken. It is circular.
complex-question-fallacy (plurium interrogationum, many questions fallacy)
Where someone asks a question that presupposes something that has not been proven or accepted by all the people involved.
e.g. The question ‘Is your husband at home or at work?’ is fallacious because it restricts the possible responses to ‘at home’ or ’at work‘. If it is unreasonable for the person being questioned to be restricted in that way, the question is fallacious.
confusion of necessary with a sufficient condition
A necessary condition is a condition that must be present for an event to occur whilst a sufficient condition is a condition or set of conditions that will actually produce the event. This fallacy occurs when you assume that a necessary condition of an event is sufficient for the event to occur. A necessary condition must be there, but it alone does not provide sufficient cause for the event to occur.
e.g. I don't know why the car won't run, there is plenty of petrol in the tank.
continuum fallacy (sorites fallacy)
Improperly rejecting a claim because it is not as precise as one would like it to be. The Sorites paradox refers to situations where there are many discrete states while the continuum fallacy refers to situations where there is (or appears to be) a continuum of states, such as temperature. Is a room hot or cold?
Logical form:
P1: X is one extreme and Y is the opposite extreme.
P2: There is no definable point where X becomes Y.
C: Therefore, there is no difference between X and Y.
correlation proves causation (cum hoc ergo propter hoc)
A faulty assumption that correlation between two variables implies that one causes the other.
See questionable cause.
D
definition, fallacy of (definist fallacy, Socratic fallacy)
Where definitions can fail to adequately explain terms. They may: be overly broad, use obscure or ambiguous language, or contain circular reasoning.
Major classifications: overly broad, overly narrow, mutually exclusive definitions, incomprehensible definitions, circular definitions.
division, fallacy of
Assuming that something true of a thing must also be true of all or some of its parts.
Logical form:
e.g. Americans, on average, weigh more than Europeans. So, my European cousin who is visiting in a few weeks is going to be thinner than I am.
E
equivocation
When a key term or phrase in an argument is used in an ambiguous way, with one meaning in one portion of the argument and then another meaning in another portion of the argument.
e.g. Nothing is better than a cold beer but a warm beer is better than nothing. So a warm beer is better than a cold beer.
etymological fallacy
Maintaining that the original or historical meaning of a word or phrase is necessarily similar to its actual present-day meaning.
e.g. To claim that the verb ‘orient’ properly means ‘to arrange something to face east’.
F
fallacies of omission
Where contrary evidence is left out or ignored and only evidence that supports an argument is presented. Often the argument is directed away from the missing information.
See stacking the deck, appeal to ignorance,
hypothesis contrary to fact, loaded question, argument from the negative.
fallacy of accent
This refers to the subtle variations in meaning that are achieved through shades of intonation and the supra-segmental features of voice tone. First noted in Aristotle's ‘On Sophistical Refutations‘1*. These are difficult to render into written examples as written language lacks the repertoire of intonation that is available in speech.
Prosecutor: Where were you on the night of the 16th?
Without an accent on 'you' this is a straight-forward question. With a harsh and strident accent on the 'you' it is an violent accusation.
fallacy of Accident (destroying the exception, dicto simpliciter ad dictum secundum quid)
A deductively valid but unsound argument occurring in a statistical syllogism when an exception to a general rule is not recognised. The fallacy results from concluding that the scope of a generalization refers to uncharacteristic or incongruous examples.
This fallacy may occur when limited generalizations (‘some’, ‘sometimes’ and ‘somewhere’) are mixed with A-type categorical statements (‘all’, ‘always’ and ‘everywhere’), often when no quantifiers like ‘some’ or ‘many’ or qualifiers such as ‘rarely’ are used to mark off what is or may be excepted in the generalization.
Example:
Premise 1. Cutting people with knives is a crime.
Premise 2. Surgeons cut people with knives.
Conclusion. Surgeons are criminals.
fallacies of ambiguity
Where there is some confusion over meaning, specifically over the members referred to by a term or phrase used in an argument. An unstated premiss asserts a (false) relation between the two meanings of the confused term (usually a homonym).
e.g. All beetles have six legs. John Lennon is a Beatle, so John Lennon has six legs.
See equivocation, amphiboly, accent, figure of speech.
See a good article at researchgate.net.
fallacy of composition
To assume that something that is true of part of a whole must also be true of the whole.
e.g. Richard is the smartest student in our school. Richard is in my class, so my class must be the smartest in the school.
fallacies of intrusion
ad hominem, argument from authority.
fallacy of presumption
Where an unwarranted assumption is used to draw a conclusion.
Common examples of presumptive fallacies are begging the question, complex question, and false dichotomy.
fallacies of relevance
Using examples or appeals to evidence or people who are not relevant to the argument. The argument may be compelling psychologically but not necessarily rationally compelling. What makes something a fallacy is that it fails to be rationally compelling, once we have carefully considered it.
Specific fallacies of relevance: ad hominem, straw man, tu quoque, genetic fallacy, appeal to consequence, appeal to authority, red herring fallacy.
false analogy (false equivalence, faulty analogy, appeal to equality, apples and oranges)
To assume that because two things are alike in one or more respects, they are necessarily alike in another respect.
e.g. People who buy stocks are no different to people who bet on horse racing. They both risk their money with little chance of making any.
false attribution (appeal to authority)
Where an advocate appeals to an irrelevant, unqualified, unidentified, biased or fabricated source in support of an argument.
e.g. Pauline Hanson says that climate change is not affecting the Great Barrier Reef. Therefore, climate change is a myth.
false dilemma (false dichotomy, fallacy of bifurcation, black-or-white fallacy)
Reasoning from an either-or position whilst excluding other relevant possibilities.
e.g. There's nothing worth watching on TV tonight so I'll have to get drunk.
e.g. Are you gay or straight?
false equivalence (false analogy, apples and oranges)
An assertion is deemed true or false based on an assumed pretense of equality, where what exactly is ‘equal’ is not made clear, and not supported by the argument.
e.g. Many scientists believe that climate change is happening but many people think it's a hoax. So it's reasonable to remain undecided.
faulty generalisation
When we we make a generalization on the basis of insufficient evidence. Relying on too small of a sample or an unrepresentative sample to support a generalization. The premises are related to the conclusion but provide only support.
Often follows the format:
Proportion Q of the sample has attribute A.
Therefore, the proportion Q of the population has attribute A.
e.g. If one sees only white swans, one may think that all swans are white.
Other variants: Accident, No true Scotsman, Cherry picking, False analogy, Hasty generalization, Misleading vividness, Overwhelming exception, Pathetic fallacy, Thought-terminating cliché.
G
gambler's fallacy (Related to ludic fallacy)
The belief that separate, independent events, can affect the likelihood of another random event.
e.g. If a coin flip lands on heads 10 times in a row, the belief that it is ‘due to land on tails’.
genetic fallacy (fallacy of origins, fallacy of virtue)
Where a conclusion is based solely on someone's or something's history, origin, or source rather than its current meaning or context. This overlooks any difference to be found in the present situation, typically transferring the positive or negative esteem from the earlier context. Note: appeal to authority and ad hominem are types of genetic fallacy.
e.g. You can't believe him on health issues, he is overweight himself!
e.g. The Nazis developed Volkswagen. They must be terrible cars.
H
hasty generalization (fallacy of: pars pro toto, insufficient statistics, insufficient sample, the lonely fact, leaping to a conclusion, hasty induction, secundum quid, converse accident)
Basing a broad conclusion on a small sample. It involves drawing a conclusion about all or many instances of a phenomenon on the basis of one or a few instances of that phenomenon.
Example: Several Liberal politicians have been exposed conducting adulterous affairs. Therefore, all Liberal politicians are adulterers.
historian's fallacy
When one assumes that decision makers of the past viewed events from the same perspective and having the same information as those subsequently analyzing the decision.
Example&colon: The notion that Japan's surprise attack on Pearl Harbor should have been predictable because of the many indications that an attack was imminent, overlooks, the presence of innumerable conflicting signs which suggested possibilities other than an attack on Pearl Harbor.
homunculus fallacy
Where a ‘middle-man’ is used for explanation, without actually explaining the real nature of a function or a process. Instead, it explains the concept in terms of the concept itself, without first defining or explaining the original concept.
e.g. Explaining thought as something produced by a little thinker inside the head.
hypothesis contrary to fact (argumentum ad speculum)
Trying to prove something in reality using examples or arguments from a fantasy world. The idea is that hypothetically if A happened, then B would be the result of it. The validity of such an argument is directly proportional to the
probability of the imagined circumstance coming about.
e.g. If the Japanese had won the battle of the Coral Sea, we would all be speaking Japanese now.
I
incomplete comparison
An incomplete assertion that cannot possibly be refuted. Such as saying ‘Product x is better.’ without stating what it is better than.
inconsistency
When someone makes contradictory claims.
e.g. I'm all for equal rights for women. I just think a woman's place is in the home.
inconsistent comparison (false equivalence)
Where different methods of comparison are used, leaving one with a false impression of the whole comparison.
e.g. An advertisement might say: ‘product X is less expensive than product A, has better quality than product B, and has more features than product C’. This gives the impression that product X is better than products A, B, and C in all respects, but only says: ‘product X is not the most expensive, lowest quality, or fewest featured product on the market’.
inflation of conflict
Reasoning that because authorities cannot agree precisely on an issue, no conclusions can be reached at all, and minimizing the credibility of the authorities, as a result. This is a form of black-or-white thinking: either we know the exact truth, or we know nothing at all.
irrelevant conclusion (Ignoratio elenchi — ignoring refutation, missing the point)
An argument that may or may not be logically valid and sound, but (whose conclusion) does not address the issue in question. It falls into the broad class of relevance fallacies.
e.g. A: Does the law allow me to do that? B: The law should allow you to do that because of this and that.
The question was not if the law should allow, but if it does allow.
is ought (Naturalistic fallacy)
The assumption that because things are a certain way, they should be or are meant to be that way. Or if something is not happening now, then it should not occur. This fallacy asserts that the status quo should be maintained simply for its own sake.
e.g. If nature doesn't make it, we shouldn't have it.
J
K
kettle logic (Fr. la logique du chaudron)
A rhetorical device wherein one uses multiple arguments to defend a point, but the arguments are inconsistent with each other.
e.g.From an example used by Sigmund Freudin The ‘Interpretation of Dreams’. Freud relates the story of a man who was accused by his neighbour of having returned a kettle in a damaged condition. He offers three arguments in his defence :
That he had returned the kettle undamaged.
That it was already damaged when he borrowed it.
That he had never borrowed it in the first place.
Though the three arguments are inconsistent, Freud notes that even if one is found to be true then the man is exhonerated.
Freud believes kettle logic is often employed in dreams.
L
loaded question
A question is asked that presupposes something that has not been proven or accepted by all the people involved. This fallacy is often used rhetorically: the question attempts to limit direct replies to be those that serve the questioner's agenda.
e.g. The traditional example is the question ‘Have you stopped beating your wife?‘
ludic fallacy (games fallacy)
The belief that the outcomes of a non-regulated random occurrence can be encapsulated by a statistic. Fails to take into account unknown unknowns in determining the probability an event will take place.
e.g. Mistaking the randomness in casinos for that in real life.
M
mind projection fallacy
When someone thinks that the way they see the world reflects the way the world really is. Can go as far as accepting the real existence of imagined objects.
e.g. Someone thinks that because they enjoy chocolate, everyone else must like it too.
misleading vividness
When a small number of dramatic events are cited to claim that something is more prevalent than it actually is based on statistics.
Form: Dramatic or vivid event X occurs (not in accord with the majority of the statistical evidence).
Therefore events of type X are likely to occur.
moving the goalposts (raising the bar)
An argument in which evidence presented in response to a specific claim is dismissed and some other (often greater) evidence is demanded. The name is a metaphor derived from goal-based sports, that means to change the criterion of a process or competition while it is still in progress, in such a way that the new goal offers one side an advantage or disadvantage.
e.g. Birther movement people demanded the release of Barack Obama's birth certificate to prove his US citizenship.
After Obama released a short-form version of his birth certificate, they demanded the release of the long form version. Afte this was done they demanded college and school records, and even proof that his mother was in the hospital at the time.
N
nirvana fallacy (perfect solution fallacy)
When solutions to problems are rejected because they are not perfect. It can also refer to the tendency to assume there is a perfect solution to a particular problem.
e.g. Seat belts are a bad idea. People are still going to die in car crashes.
no true Scotsman (appeal to purity,)
Attempting to protect a universal generalization from a counter-example by tautologically (saying the same thing twice with different words) excluding the counter-example.
Rather than abandoning the universal generalization or providing evidence that would disqualify the counterexample, this fallacy involves offering a modified generalization to definitionally exclude the specific case and counterexamples like it by appeal to rhetoric as opposed to an objective criterion. The rhetoric takes the form of emotionally charged purity platitudes such as ‘true, pure, genuine, authentic, real’, etc.
Example:
Person A: ‘No Scotsman puts sugar on his porridge.’
Person B: ‘But my uncle Angus is a Scotsman and he puts sugar on his porridge.’
Person A: ‘But no true Scotsman puts sugar on his porridge.’
O
onus probandi (see burden of proof)
A particular case of the ‘argumentum ad ignorantiam’ fallacy, where the person contesting an assertion is asked to prove it false. From Latin ‘onus probandi incumbit ei qui dicit, non ei qui negat’ — the burden of proof is on the person who makes the claim, not on the person who denies or questions the claim.
e.g. I believe in ghosts. Can you prove they don't exist?
ought is
When you assume that the way you want things to be is the way they are. This is also called wishful thinking: believing what you want to be true is true, no matter the evidence.
e.g. I know there is a God. Life would be meaningless otherwise.
over-generalization
Another name for hasty generalization.
overwhelming exception
An accurate generalization that comes with qualifications which eliminate so many cases that what remains is much less impressive than the initial statement might have led one to assume. An informal fallacy of generalization.
e.g. Besides charitable works, community cohesion, rehabilitation, and helping children learn values, religion poisons everything.
P
pars pro toto fallacy (Latin for 'a part (taken) for the whole'.) A subset of hasty generalization or overgeneralisation.
Where the results of a few specific cases are applied to a larger group.
pathetic fallacy (reification fallacy.)
When an inanimate object is declared to have characteristics of animate objects. A specific type of personification.
e.g. The sun smiled on their happy occasion.
post hoc (post hoc ergo propter hoc — after this, therefore because of this.)
(Coincidental correlation, Correlation proves causation, False cause)
X happened then Y happened. Therefore X caused Y.
e.g. The rooster crows every morning before the sun comes up. The rooster crowing must cause the sun to rise.
proof by verbosity (argumentum verbosium, proof by intimidation, shotgun argumentation (
Making an argument purposely difficult to understand in an attempt to intimidate your audience into accepting it.
prosecutors fallacy
When the probability of innocence given the evidence is wrongly assumed to equal an infinitesimally small probability that that evidence would occur if the defendant was innocent.
e.g. The probability that this nurse's shifts would coincide with so many deaths and resuscitations by chance is 1 in 342 million, so she must be guilty.
psychogenetic fallacy (Bulverism)
Inferring some psychological reason why an argument is made, then assuming it is invalid as a result. It is wrong to assume that if the origin of an idea comes from a biased mind, then the idea itself must also be a false.
This is a combination of circular reasoning and the genetic fallacy.
Logical Form: Person 1 made argument X because of the psychological reason Y. ... Therefore, X is not true.
e.g. P1: White people are not racists. P2: You say that because you are white.
psychologist's fallacy
When an observer assumes that his or her subjective experience reflects the true nature of an event.
e.g. I didn't think that roller coaster was fun. That means that the roller coaster is not a fun ride.
Q
questionable Cause (coincidental correlation; correlation without causation)
Is a general type error with many variants. A causal connection is assumed because of association, especially sequential or simultaneouse occurrences. From Latin ‘Post hoc ergo propter hoc’ for ‘after this, therefore because of this’.
e.g. We never had a problem with this elevator until you moved into the building.
quoting out of context (contextomy)
The selective excerpting of words from their original context in a way that distorts the source's intended meaning.
Arguments based on this fallacy typically take a straw man form, to misrepresent an opponent's position or an appeal to authority form, where the authority is misquoted so as to apparantly support some position.
R
red herring (fallacies of misdirection)
When attention is diverted from the real issue by introducing a proposition or argument with little or no relevance to the first. In general, any logical inference based on fake arguments, intended to replace the lack of real arguments or to replace implicitly the subject of the discussion.
e.g. I don't support gay marriage among homosexuals. Anyway, taxes on married people are ridiculously high.
e.g. A politician is asked about a certain policy but discusses a related topic instead.
reductio ad absurdum
A form of argument that attempts to establish a claim by showing that the opposite scenario would lead to absurdity or contradiction. It can be used to disprove a statement by showing that it would inevitably lead to a ridiculous, absurd, or impractical conclusion, or to prove a statement by showing that if it were false, then the result would be absurd or impossible.
e.g. The Earth cannot be flat. Otherwise, we would find people falling off the edge.
referential fallacy (a version of reification fallacy)
An argument or proposition that assumes that all words refer to existing things and that the meaning of words reside in the things they refer to. This discounts the notion that words possibly refer to non-real objects (e.g. Pegasus) or that their meaning may come from how they are used.
e.g. ‘Nobody’ was coming up the stairs.
regression fallacy
Ascribing a cause where none exists. The flaw is failing to account for natural fluctuations. It is frequently a special kind of the post hoc fallacy.
e.g. A man suffering acute pain went to a doctor. After this the pain subsided a little. Therefore, the doctor's treatment relieved his pain.
reification (a version of referential fallacy, pathetic fallacy)
When an abstraction (abstract belief or hypothetical construct) is treated as if it were a concrete, real event or physical entity. In other words, it is the error of treating as a ‘real thing’ something which is not a real thing, but merely an idea.
relevance, fallacies of
Where irrelevant matters are brought into an argument. The arguments in whivch they occur have premises that are logically irrelevant to the conclusion, but seem to be relevant psychologically, and the conclusion seems to follow from the premises. the premises are connected to the conclusion emotionally or figuratively, but not logically.
Examples: argumentum ad baculum, argumentum ad hominem, tu quoque, argumentum ad ignorantiam, argumentum ad misericordiam, argumentum ad populum, appeal to authority, appeal to emotions, straw man, .
retrospective determinism
Reasoning that because something happened in given circumstances, it is bound to happen, and will always happen given those circumstances.
e.g. It should have been obvious that Alexander the Great could not conquer all of Asia. It is impossible to make that journey and not fall ill.
S
single cause fallacy (Causal oversimplification, Reduction fallacy)
Assuming that there is one, simple cause of an outcome when in reality it may have been caused by a number of only jointly sufficient causes.
e.g. X occurred after Y. Therefore, Y caused X (although X was also a result of A,B,C... etc.)
slippery slope (thin edge of the wedge)
A course of action is rejected because it is thought it will start a chain reaction resulting in undesirable consequences. It involves an acceptance that a succession of events will occur without conclusive evidence that this will happen. In essence it is an appeal to probability fallacy.
e.g. If we legalize marijuana, then that will lead to every drug in the world becoming legal.
special pleading (thin edge of the wedge)
Where a proponent of a position attempts to cite something as an exemption to a generally accepted rule or principle without justifying the exemption.
e.g. Everyone should wait their turn in line. But, I need to go to the front because I am in a hurry.
stacking the deck
The argument ignores evidence or examples that disagree or disprove their conclusion and only provide evidence in support of their case.
e.g. The ‘no true scotsman’ fallacy is a specific type of ‘stacking the deck’ that defines something so narrowly that it excludes obvious examples then says that those examples are not ‘truly’ a part of what is being defined because they don't meet the narrow definition.
straw man
Refute another person's argument by addressing only a weak or distorted version of it. The straw man is not the actual argument under discussion.
e.g. Pro-choice is absurd. How could anyone support killing an innocent human being?
suppressed correlative (fallacy of: lost contrast, suppressed relative.)
An argument that tries to redefine one of two mutually exclusive options so that one alternative encompasses the other.
Person 1: ‘Things are either mysterious or not mysterious. Exactly when an earthquake will strike is still a mystery, but how blood circulates in the body is not.’
Person 2: ‘Everything is mysterious. There are still things to be learned about how blood circulates.’
T
thought-terminating cliché
To end a debate with a commonly used phrase or cliché, sometimes passing as folk wisdom, to quell cognitive dissonance, and distract attention from the lack of cogent argument.
If the phrase is relevant it may not be a fallacy. But if not is a taype or red herring or relevance fallacy.
e.g. It is what it is.
e.g. The Lord moves in mysterious ways.
tu quoque (‘you too‘, ‘you also’, appeal to hypocrisy.).
A type of Ad Hominem that answers a criticism by claiming the same criticism applies to the opponent. Thus avoiding answering their criticism.
e.g. Councillor 1: You take bribes from developers. Councillor 2: So do you.
two wrongs
Where you justify an act or belief by pointing out in others a similar act or belief. Another form occurs when you dismiss a criticism of your action or belief, because your critic is acting or believing in a similar way.
e.g. I'm tailgating her, because she cut me off!
Big deal! Lots of people cheat too
U
V
W
wishful thinking
A specific type of appeal to emotion where a decision is made according to what might be pleasing to imagine, rather than according to evidence or reason.
wrong direction
Where cause and effect are said to be reversed. The problem behind the fallacy is that data correlation does not prove what caused what.
e.g. The tendency to violent behaviour may be directly proportional to the number of hours of TV watched per day. But what causes what can't be induced from the data: TV makes children more violent or violent children watch more TV than non-violent children.
X
Y
Z
1. Aristotle On Sophistical Refutations Part 4.
List of formal logical fallacies
List of informal logical fallacies