Fallacies

Negative conclusion from affirmative premises (illicit affirmative)

a categorical syllogism has a negative conclusion but affirmative premises.[12]

Affirmative conclusion from a negative premise (illicit negative)

a categorical syllogism has a positive conclusion, but at least one negative premise.[12]

Fallacy of four terms (quaternio terminorum)

a categorical syllogism that has four terms.[13]

Fallacy of exclusive premises

a categorical syllogism that is invalid because both of its premises are negative.[12]

Illicit major

a categorical syllogism that is invalid because its major term is not distributed in the major premise but distributed in the conclusion.[12]

Illicit minor

a categorical syllogism that is invalid because its minor term is not distributed in the minor premise but distributed in the conclusion.[12]

Ambiguous middle term

a common ambiguity in syllogisms in which the middle term is equivocated.[22]

Thought-terminating cliché

a commonly used phrase, sometimes passing as folk wisdom, used to quell cognitive dissonance, conceal lack of thought-entertainment, move on to other topics etc. but in any case, end the debate with a cliché—not a point.

Suppressed correlative

a correlative is redefined so that one alternative is made impossible.[19]

Special pleading

a proponent of a position attempts to cite something as an exemption to a generally accepted rule or principle without justifying the exemption.

Proof by assertion

a proposition is repeatedly restated regardless of contradiction; sometimes confused with argument from repetition (argumentum ad infinitum, argumentum ad nauseam)

Historical fallacy

a set of considerations is thought to hold good only because a completed process is read into the content of the process which conditions this completed result.[31]

Survivorship bias

a small number of successes of a given process are actively promoted while completely ignoring a large number of failures

Syllogistic fallacies

logical fallacies that occur in syllogisms.

Ludic fallacy

the belief that the outcomes of non-regulated random occurrences can be encapsulated by a statistic; a failure to take into account unknown unknowns in determining the probability of events taking place.[35]

Denying the antecedent

the consequent in an indicative conditional is claimed to be false because the antecedent is false; if A, then B; not A, therefore not B.[11]

Gambler's fallacy

the incorrect belief that separate, independent events can affect the likelihood of another random event. If a fair coin lands on heads 10 times in a row, the belief that it is "due to the number of times it had previously landed on tails" is incorrect.[55]

Intentionality fallacy

the insistence that the ultimate meaning of an expression must be consistent with the intention of the person from whom the communication originated (e.g. a work of fiction that is widely received as a blatant allegory must necessarily not be regarded as such if the author intended it not to be so.)[34]

Fallacy of the undistributed middle

the middle term in a categorical syllogism is not distributed.[14]

Inductive fallacy

A more general name to some fallacies, such as hasty generalization. It happens when a conclusion is made of premises that lightly support it.

Propositional fallacies

A propositional fallacy is an error in logic that concerns compound propositions. For a compound proposition to be true, the truth values of its constituent parts must satisfy the relevant logical connectives that occur in it (most commonly: <and>, <or>, <not>, <only if>, <if and only if>). The following fallacies involve inferences whose correctness is not guaranteed by the behavior of those logical connectives, and hence, which are not logically guaranteed to yield true conclusions.

Quantification fallacies

A quantification fallacy is an error in logic where the quantifiers of the premises are in contradiction to the quantifier of the conclusion.

Motte-and-bailey fallacy

The arguer conflates two similar positions, one modest and easy to defend (the "motte") and one much more controversial (the "bailey"). The arguer advances the controversial position, but when challenged, they insist that they are only advancing the more modest position.[23]

Inflation of conflict

The experts of a field of knowledge disagree on a certain point, so the scholars must know nothing, and therefore the legitimacy of their entire field is put to question.[33]

Post hoc ergo propter hoc (Latin for "after this, therefore because of this"; temporal sequence implies causation)

X happened, then Y happened; therefore X caused Y.[52]

Homunculus fallacy

a "middle-man" is used for explanation; this sometimes leads to regressive middle-men. Explains 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. Explaining thought as something produced by a little thinker, a sort of homunculus inside the head, merely explains it as another kind of thinking (as different but the same).[32]

Reification (concretism, hypostatization, or the fallacy of misplaced concreteness)

a fallacy of ambiguity, 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 that is not a real thing, but merely an idea.

Cum hoc ergo propter hoc (Latin for "with this, therefore because of this"; correlation implies causation; faulty cause/effect, coincidental correlation, correlation without causation)

a faulty assumption that, because there is a correlation between two variables, one caused the other.[51]

Prosecutor's fallacy

a low probability of false matches does not mean a low probability of some false match being found.

Fallacy of accent

a specific type of ambiguity that arises when the meaning of a sentence is changed by placing an unusual prosodic stress, or when, in a written passage, it's left unclear which word the emphasis was supposed to fall on.

Appeal to probability

a statement that takes something for granted because it would probably be the case (or might be the case).[5][6]

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.[47]

Overwhelming exception

an accurate generalization that comes with qualifications that eliminate so many cases that what remains is much less impressive than the initial statement might have led one to assume.[50]

False attribution

an advocate appeals to an irrelevant, unqualified, unidentified, biased or fabricated source in support of an argument.

False analogy

an argument by analogy in which the analogy is poorly suited.[48]

Existential fallacy

an argument that has a universal premise and a particular conclusion.[12]

If-by-whiskey

an argument that supports both sides of an issue by using terms that are selectively emotionally sensitive.

Accident

an exception to a generalization is ignored.[45]

Psychologist's fallacy

an observer presupposes the objectivity of their own perspective when analyzing a behavioral event.

Divine fallacy (argument from incredulity)

arguing that, because something is so incredible or amazing, it must be the result of superior, divine, alien or paranormal agency.[20]

Moving the goalposts (raising the bar)

argument in which evidence presented in response to a specific claim is dismissed and some other (often greater) evidence is demanded.

Informal fallacies

arguments that are fallacious for reasons other than structural (formal) flaws and usually require examination of the argument's content.[16]

Regression fallacy

ascribes cause where none exists. The flaw is failing to account for natural fluctuations. It is frequently a special kind of post hoc fallacy.

Referential fallacy[39]

assuming all words refer to existing things and that the meaning of words reside within the things they refer to, as opposed to words possibly referring to no real object or that the meaning of words often comes from how they are used.

Argument from ignorance (appeal to ignorance, argumentum ad ignorantiam)

assuming that a claim is true because it has not been or cannot be proven false, or vice versa.[57]

Fallacy of division

assuming that something true of a thing must also be true of all or some of its parts.[27]

Fallacy of composition

assuming that something true of part of a whole must also be true of the whole.[26]

Argument to moderation (false compromise, middle ground, fallacy of the mean, argumentum ad temperantiam)

assuming that the compromise between two positions is always correct.[17]

Conjunction fallacy

assumption that an outcome simultaneously satisfying multiple conditions is more probable than an outcome satisfying a single one of them.[9]

Argument from fallacy (also known as the fallacy fallacy)

assumption that if an argument for some conclusion is fallacious, then the conclusion is false.[7]

Hasty generalization (fallacy of insufficient statistics, fallacy of insufficient sample, fallacy of the lonely fact, hasty induction, secundum quid, converse accident, jumping to conclusions)

basing a broad conclusion on a small sample or the making of a determination without all of the information required to do so.[49]

Wrong direction (reverse causation)

cause and effect are reversed. The cause is said to be the effect and vice versa.[53] The consequence of the phenomenon is claimed to be its root cause.

Definitional retreat

changing the meaning of a word to deal with an objection raised against the original wording.[1]

Affirming a disjunct

concluding that one disjunct of a logical disjunction must be false because the other disjunct is true; A or B; A, therefore not B.[11]

Modal fallacy

confusing possibility with necessity.[15]

Double counting

counting events or occurrences more than once in probabilistic reasoning, which leads to the sum of the probabilities of all cases exceeding unity.

False equivalence

describing a situation of logical and apparent equivalence, when in fact there is none.

Inconsistent comparison

different methods of comparison are used, leaving a false impression of the whole comparison.

Appeal to the stone (argumentum ad lapidem)

dismissing a claim as absurd without demonstrating proof for its absurdity.[56]

Onus probandi

from the 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). It is a particular case of the argumentum ad ignorantiam fallacy, here the burden is shifted on the person defending against the assertion. Also known as "shifting the burden of proof".

Continuum fallacy (fallacy of the beard, line-drawing fallacy, sorites fallacy, fallacy of the heap, bald man fallacy)

improperly rejecting a claim for being imprecise.[18]

Ecological fallacy

inferences about the nature of specific individuals are based solely upon aggregate statistics collected for the group to which those individuals belong.[24]

Naturalistic fallacy fallacy[37] (anti-naturalistic fallacy)[38]

inferring an impossibility to infer any instance of ought from is from the general invalidity of is-ought fallacy, mentioned above. For instance, is {\displaystyle P\lor \neg P} P \lor \neg P does imply ought {\displaystyle P\lor \neg P} P \lor \neg P for any proposition {\displaystyle P} P, although the naturalistic fallacy fallacy would falsely declare such an inference invalid. Naturalistic fallacy fallacy is a type of argument from fallacy.

Naturalistic fallacy

inferring evaluative conclusions from purely factual premises[36] in violation of fact-value distinction. For instance, inferring ought from is (sometimes referred to as the is-ought fallacy) is an instance of naturalistic fallacy. Also, naturalistic fallacy in the stricter sense defined in the section "Conditional or questionable fallacies" (below) is a variety of this broader sense of naturalistic fallacy. Naturalistic fallacy is the inverse of moralistic fallacy.

Moralistic fallacy

inferring factual conclusions from purely evaluative premises in violation of fact-value distinction. For instance, inferring is from ought is an instance of moralistic fallacy. Moralistic fallacy is the inverse of naturalistic fallacy defined below.

Incomplete comparison

insufficient information is provided to make a complete comparison.

Misleading vividness

involves describing an occurrence in vivid detail, even if it is an exceptional occurrence, to convince someone that it is a problem.

Fallacy of the single cause (causal oversimplification[54])

it is assumed 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.

No true Scotsman

makes a generalization true by changing the generalization to exclude a counterexample.[46]

McNamara fallacy (quantitative fallacy)

making a decision based only on quantitative observations, discounting all other considerations.

Base rate fallacy

making a probability judgment based on conditional probabilities, without taking into account the effect of prior probabilities.[8]

Furtive fallacy

outcomes are asserted to have been caused by the malfeasance of decision makers.

Begging the question (petitio principii)

providing what is essentially the conclusion of the argument as a premise.[40][41][42][43]

Faulty generalization

reach a conclusion from weak premises. Unlike fallacies of relevance, in fallacies of defective induction, the premises are related to the conclusions yet only weakly buttress the conclusions. A faulty generalization is thus produced.

Etymological fallacy

reasoning that the original or historical meaning of a word or phrase is necessarily similar to its actual present-day usage.[25]

Fallacy of quoting out of context (contextotomy, contextomy; quotation mining)

refers to the selective excerpting of words from their original context in a way that distorts the source's intended meaning.[28]

Nirvana fallacy (perfect-solution fallacy)

solutions to problems are rejected because they are not perfect.

Fallacy of many questions (complex question, fallacy of presuppositions, loaded question, plurium interrogationum)

someone asks a question that presupposes something that has not been proven or accepted by all the people involved. This fallacy is often used rhetorically so that the question limits direct replies to those that serve the questioner's agenda.

Mind projection fallacy

subjective judgments are "projected" to be inherent properties of an object, rather than being related to personal perceptions of that object.

Affirming the consequent

the antecedent in an indicative conditional is claimed to be true because the consequent is true; if A, then B; B, therefore A.[11]

Retrospective determinism

the argument that because an event has occurred under some circumstance, the circumstance must have made its occurrence inevitable.

Historian's fallacy

the assumption that decision makers of the past viewed events from the same perspective and had the same information as those subsequently analyzing the decision.[30] (Not to be confused with presentism, which is a mode of historical analysis in which present-day ideas, such as moral standards, are projected into the past.)

Equivocation

the misleading use of a term with more than one meaning (by glossing over which meaning is intended at a particular time).[21]

Circular reasoning (circulus in demonstrando)

the reasoner begins with what he or she is trying to end up with; sometimes called assuming the conclusion.

Masked-man fallacy (illicit substitution of identicals)

the substitution of identical designators in a true statement can lead to a false one.[10]

False dilemma (false dichotomy, fallacy of bifurcation, black-or-white fallacy)

two alternative statements are held to be the only possible options when in reality there are more.[29]

Proving too much

using a form of argument that, if it were valid, could be used to reach an additional, invalid conclusion.

False authority (single authority)

using an expert of dubious credentials or using only one opinion to sell a product or idea. Related to the appeal to authority fallacy.

Kettle logic

using multiple, jointly inconsistent arguments to defend a position.[dubious - discuss]

Loaded label

while not inherently fallacious, use of evocative terms to support a conclusion is a type of begging the question fallacy. When fallaciously used, the term's connotations are relied on to sway the argument towards a particular conclusion. For example, an organic foods advertisement that says "Organic foods are safe and healthy foods grown without any pesticides, herbicides, or other unhealthy additives." Use of the term "unhealthy additives" is used as support for the idea that the product is safe.[44]