List of fallacies

Formal fallacies

• Appeal to probability – taking something for granted because it would probably be the case.
• Argument from fallacy – the assumption that, if a particular argument for a "conclusion" is fallacious, then the conclusion by itself is false.
• Base rate fallacy – making a probability judgement based on conditional probabilities, without taking into account the effect of prior probabilities.
• Conjunction fallacy – the assumption that an outcome simultaneously satisfying multiple conditions is more probable than an outcome satisfying a single one of them.
• nocat=y fallacy – where the conclusion does not logically follow from the premise.
• Masked-man fallacy – the substitution of identical designators in a true statement can lead to a false one.

  Propositional fallacies

• 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.
• 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.
• 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.

  Quantification fallacies

• Existential fallacy – an argument that has a universal premise and a particular conclusion.

  Formal syllogistic fallacies

• Affirmative conclusion from a negative premise – a categorical syllogism has a positive conclusion, but at least one negative premise.
• Fallacy of exclusive premises – a categorical syllogism that is invalid because both of its premises are negative.
• Fallacy of four terms – a categorical syllogism that has four terms.
• Illicit major – a categorical syllogism that is invalid because its major term is not distributed in the major premise but distributed in the conclusion.
• Illicit minor – a categorical syllogism that is invalid because its minor term is not distributed in the minor premise but distributed in the conclusion.
• Negative conclusion from affirmative premises – a categorical syllogism has a negative conclusion but affirmative premises.
• Fallacy of the undistributed middle – the middle term in a categorical syllogism is not distributed.
• Modal fallacy – confusing necessity with sufficiency. A condition X is necessary for Y if X is required for even the possibility of Y. X does not bring about Y by itself, but if there is no X, there will be no Y. For example, oxygen is necessary for fire. But one cannot assume that everywhere there is oxygen, there is fire. A condition X is sufficient for Y if X, by itself, is enough to bring about Y. For example, riding the bus is a sufficient mode of transportation to get to work. But there are other modes of transportation – car, taxi, bicycle, walking – that can be used.
• Modal scope fallacy – a degree of unwarranted necessity is placed in the conclusion.

  Informal fallacies

• Argument from incredulity – when someone can't imagine something to be true, and therefore deems it false, or conversely, holds that it must be true because they can't see how it could be false.
• Argument to moderation – assuming that a compromise between two positions is always correct.
• Continuum fallacy – improperly rejecting a claim for being imprecise.
• Correlative-based fallacies
• * Suppressed correlative – a correlative is redefined so that one alternative is made impossible.
• Divine fallacy – arguing that, because something is so phenomenal or amazing, it must be the result of superior, divine, alien or paranormal agency.
• 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.
• Ecological fallacy – inferring about the nature of an entity based solely upon aggregate statistics collected for the group to which that entity belongs.
• Equivocation – using a term with more than one meaning in a statement without specifying which meaning is intended.
• * Ambiguous middle term – using a middle term with multiple meanings.
• * Definitional retreat – changing the meaning of a word when an objection is raised. Often paired with moving the goalposts, as when an argument is challenged using a common definition of a term in the argument, and the arguer presents a different definition of the term and thereby demands different evidence to debunk the argument.
• * Motte-and-bailey fallacy – conflating two positions with similar properties, one modest and easy to defend and one more controversial. The arguer first states the controversial position, but when challenged, states that they are advancing the modest position.
• * Fallacy of accent – changing the meaning of a statement by not specifying on which word emphasis falls.
• * Persuasive definition – purporting to use the "true" or "commonly accepted" meaning of a term while, in reality, using an uncommon or altered definition.
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• Etymological fallacy – assuming that the original or historical meaning of a word or phrase is necessarily similar to its actual present-day usage.
• Fallacy of composition – assuming that something true of part of a whole must also be true of the whole.
• Fallacy of division – assuming that something true of a composite thing must also be true of all or some of its parts.
• False attribution – appealing to an irrelevant, unqualified, unidentified, biased or fabricated source in support of an argument.
• * Fallacy of quoting out of context – selective excerpting of words from their original context to distort the intended meaning.
• False authority – using an expert of dubious credentials or using only one opinion to promote a product or idea. Related to the appeal to authority.
• False dilemma – two alternative statements are given as the only possible options when, in reality, there are more.
• False equivalence – describing two or more statements as virtually equal when they are not.
• Feedback fallacy – believing in the objectivity of an evaluation to be used as the basis for improvement without verifying that the source of the evaluation is a disinterested party.
• Historian's fallacy – assuming that decision-makers of the past had identical information as those subsequently analyzing the decision. This is not to be confused with presentism, in which present-day ideas and perspectives are anachronistically projected into the past.
• Historical fallacy – believing that certain results occurred only because a specific process was performed, though said process may actually be unrelated to the results.
• * Baconian fallacy – supposing that historians can obtain the "whole truth" via induction from individual pieces of historical evidence. The "whole truth" is defined as learning "something about everything", "everything about something", or "everything about everything". In reality, a historian "can only hope to know something about something".
• Homunculus fallacy – using a "middle-man" for explanation; this sometimes leads to regressive middle-men. It explains a concept in terms of the concept itself without explaining its real nature.
• – arguing that, if experts in a field of knowledge disagree on a certain point within that field, no conclusion can be reached or that the legitimacy of that field of knowledge is questionable.
• If-by-whiskey – an argument that supports both sides of an issue by using terms that are emotionally sensitive and ambiguous.
• Incomplete comparison – insufficient information is provided to make a complete comparison.
• 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.
• Kettle logic – using multiple, jointly inconsistent arguments to defend a position.
• Ludic fallacy – failing to take into account that non-regulated random occurrences unknown unknowns can affect the probability of an event taking place.
• Lump of labour fallacy – the misconception that there is a fixed amount of work to be done within an economy, which can be distributed to create more or fewer jobs.
• McNamara fallacy – making an argument using only quantitative observations and discounting subjective information that focuses on quality.
• Mind projection fallacy – assuming that a statement about an object describes an inherent property of the object, rather than a personal perception.
• Moralistic fallacy – inferring factual conclusions from evaluative premises in violation of fact–value distinction. Moralistic fallacy is the inverse of naturalistic fallacy.
• Moving the goalposts – argument in which evidence presented in response to a specific claim is dismissed and some other evidence is demanded.
• Nirvana fallacy – solutions to problems are rejected because they are not perfect.
• Package deal – treating essentially dissimilar concepts as though they were essentially similar.
• Proof by assertion – a proposition is repeatedly restated regardless of contradiction; sometimes confused with argument from repetition.
• Prosecutor's fallacy – a low probability of false matches does not mean a low probability of false match being found.
• Proving too much – an argument that results in an overly generalized conclusion
• Psychologist's fallacy – an observer presupposes the objectivity of their own perspective when analyzing a behavioral event.
• Referential fallacy – assuming that 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 comes from how they are used.
• Reification – treating an abstract belief or hypothetical construct as if it were a concrete, real event or physical entity.
• Retrospective determinism – believing that, because an event has occurred under some circumstance, the circumstance must have made the event inevitable.
• Slippery slope – asserting that a proposed, relatively small, first action will inevitably lead to a chain of related events resulting in a significant and negative event and, therefore, should not be permitted.
• Special pleading – the arguer attempts to cite something as an exemption to a generally accepted rule or principle without justifying the exemption.