Намеренные логические ошибки умышленно ошибочные рассуждения

   В
процессе рассуждения необходимо
соблюдать сформулированные логикой
правила. Непреднамеренное нарушение
их из-за логической небрежности,
недостаточной логической культуры
воспринимается как логическая ошибка.

Ошибки
в логике рассуждения

   В
судебной речи могут быть следующие
логические ошибки. Если оратор,
сформулировав мысль, забывает о ней и
непроизвольно переходит к принципиально
другому положению, то происходит потеря
тезиса. В результате выступающий может
потерять исходную мысль. Здесь нужен
самоконтроль. Случается и частичная
или полная подмена тезиса. Это бывает
в том случае, когда оратор, выдвинув
определенное положение, обосновывает
фактически другое. Нередко это случается,
когда основная мысль не была сформулирована
в начале выступления четко и определенно,
и затем она поправляется или уточняется
на протяжении всей речи.

   Логические
ошибки могут возникнуть в результате
неумелой аргументации. Если аргументы
недостоверны, обладают только вероятностью,
то с их помощью невозможно обосновать
достоверный вывод. Эта ошибка называется
основным заблуждением, когда в качестве
аргумента используется заведомо ложное
положение, несуществующий факт и тому
подобное в надежде, что этого никто не
заметит. Опытный оратор, обнаружив хотя
бы один непроверенный или сомнительный
аргумент в речи оппонента, может легко
опровергнуть всю систему его рассуждений.
Вспомните, как это сделал Я.С.Киселев в
речи по делу Бердникова: «В полуправду
вкраплены фактик, другой, а то и третий,
каждый из них чем-то подтвержден… Часть
фактов верна, значит, и другая верна. А
это вовсе не так» (см. с. 366).

   В
качестве аргументов не могут использоваться
недоказанные, высказанные кем-то
предположения, например, ложные показания
подсудимого, свидетелей. Не является
истинным аргумент в следующем примере:
Органами
следствия установлено /
что Соленкову /
был нанесен удар /
ножевое ранение /
в поясничную область потерпевшему //
Мой подзащитный отрицает /
то что у него был нож /
и поясняет /
он вообще ни у кого /
из находящихся с ним /
там /
Подкуйко и Ноготкова /
ножа не видел //
Я и считаю /
что этот эпизод /
совершенно не доказан //.

   Доказательство
несостоятельно и в том случае, когда
аргументы недостаточны для обоснования
тезиса: Вину
свою он признает частично /
мне и думается /
что она доказана частично //.
Недостаточны аргументы и в таком примере:
Вина
подсудимого /
также подтверждается /
заключением судебно-медицинской
экспертизы /
и другими материалами дела //,
так как нет конкретности из-за слова
другими.
Ошибка
порочный круг состоит в том, что тезис
обосновывается аргументами, а аргументы
выводятся из этого же тезиса.

   Ошибки
в демонстрации вызываются отсутствием
логической связи между аргументами и
тезисом. Это так называемое мнимое
следование.

Ошибки
в выборе языковых средств

   Логика
рассуждения находит выражение в
конкретных языковых средствах, и это
делает возможным определить типичные
логические ошибки, к которым ведет
неточный выбор языковых средств.

   Одной
из причин нелогичности высказывания
является употребление слов без учета
их значения, например: В
нагрудном кармане его брюк обнаружено
две фотокарточки (надо:
в
переднем кармане). Нечеткая
дифференциация понятий, подмена понятий
также нарушает логику изложения: Брак
изделий — сапоги яловые в количестве 19
штук —
возложить
на ответчиков. Или:
Возвращаясь
из рейса, Короткое задремал, что явилось
результатом его столкновения со стоящим
недалеко от обочины столбом (надо:
возмещение
стоимости бракованных сапог, в количестве
19 пар;…что явилось причиной его наезда
на стоящий…). Сочетание
слов не должно быть противоречивым.
Нарушение логических связей между
словами может создать непреднамеренный
комизм: Суд
не может удовлетворить просьбу умершего
о взыскании денег на погребение. Или:
Подсудимый
Миров продолжал вместе с умершей Мировой
злоупотреблять спиртными напитками
(надо:
Суд
не может удовлетворить просьбу
родственников умершего; подсудимый
Миров продолжал вместе с Мировой, ныне
покойной…).

   Невнимательное
отношение к выбору слов ведет к
возникновению в речи алогизма —
сопоставления несопоставимых понятий:
«Действия
Босняцкого
отличаются
от других
подсудимых
не
только объемом, но и последствиями».
Или: «Среди
предъявленных
мне девяти голов
я
признал
быка». Или:
«Причиной электротравмы явилось то,
что потерпевший не
проверил отсутствие наличия электросварки»
(надо: отличаются
от действий; я опознал голову быка; не
проверил отсутствия электросварки).

   Одной
из логических ошибок является неоправданное
расширение или сужение понятия,
возникающее в результате смешения
родовых и видовых понятий, а также
нечеткое разграничение конкретных и
отвлеченных понятий: «Из магазина была
совершена кража пылесоса
и другого медицинского оборудования».
Или:
«Когда мой подзащитный возвращался с
танцев, выпадали атмосферные
осадки». Или:
«Подозреваемый Шевцов показал, что 13
февраля 1991 года он дежурил
на мероприятии». Или:
«Воеводину вменяется в вину угон
автотранспорта» (надо:
кража
пылесоса и медицинского оборудования;
шел снег (или дождь); он дежурил на вечере;
угон автотранспортного средства).

   Нелогичность
высказывания, искажение его смысла
появляется в результате несоответствия
посылки и следствия: Рост
преступности зависит от того, насколько
упорно и эффективно ведется борьба с
правонарушителями. Или:
В
целях ограждения их от хулиганских
действий соседи Петухова просят
изолировать их от Петухова (надо:
снижение
преступности; изолировать Петухова от
общества). Еще
пример: «На основании изложенного
Солонин обвиняется
в том, что он был задержан за
управление автотранспортным средством
в нетрезвом состоянии» (надо: обвиняется
в том, что управлял автотранспортным
средством в состоянии алкогольного
опьянения). Подобные
ошибки снижают качество хорошей по
содержанию речи, к тому же свидетельствуют
о нежелании судебного оратора вдумываться
в значение употребляемых слов, о
неуважении к языку и людям, которым
приходится слушать данного оратора.

Софизмы

   Мы
рассмотрели непреднамеренные логические
ошибки, которые возникают из-за отсутствия
у оратора логической культуры. Намеренные
ошибки допускаются сознательно. Это
логические уловки, умышленно ошибочные
рассуждения, выдаваемые за истинные.
Называются они софизмами. Софизм (от
греч. sophisma, хитро придумываю) — рассуждение,
кажущееся правильным, но содержащее
скрытую логическую ошибку и придающее
ложному утверждению видимость истинности.
Это рассуждение, основанное на
преднамеренном нарушении законов
логики.

   Софисты
существовали еще в Древней Греции (от
греч. sophistes — искусник, мудрец) и составляли
софистское направление в ораторском
искусстве, цель которого была — убедить
слушателей в чем-либо во что бы то ни
стало. Для этого они употребляли
умозаключения, основанные на преднамеренно
неправильном подборе исходных положений,
аргументов. Примеры софизмов: «Все люди
суть разумные существа. Жители планет
не суть люди. Следовательно, они не суть
разумные существа»; «Закон Моисеев
запрещал воровство. Закон Моисеев
потерял свою силу. Следовательно,
воровство не запрещено»; «Все металлы
— простые тела. Бронза — металл.
Следовательно, бронза — простое тело».

   Систематический
анализ софизмов был дан впервые
Аристотелем в его заключительной части
«Органона». Софизм есть ложный вывод,
неправильность которого бывает
обусловлена троякого рода причинами:
1) логическими, 2) грамматическими и 3)
психологическими^[43].

   Софизмы
являются особым приемом интеллектуального
мошенничества, попыткой выдать ложь за
истину и тем самым ввести противника в
заблуждение. Употребление их с целью
обмана является некорректным приемом
аргументации.

A fallacy is the use of invalid or otherwise faulty reasoning in the construction of an argument^[1][2] which may appear to be a well-reasoned argument if unnoticed. The term was introduced in the Western intellectual tradition by the Aristotelian De Sophisticis Elenchis.^[3]

Fallacies may be committed intentionally to manipulate or persuade by deception, unintentionally because of human limitations such as carelessness, cognitive or social biases and ignorance, or potentially due to the limitations of language and understanding of language. These delineations include not only the ignorance of the right reasoning standard, but also the ignorance of relevant properties of the context. For instance, the soundness of legal arguments depends on the context in which the arguments are made.^[4]

Fallacies are commonly divided into «formal» and «informal.» A formal fallacy is a flaw in the structure of a deductive argument which renders the argument invalid, while an informal fallacy originates in an error in reasoning other than an improper logical form.^[5] Arguments containing informal fallacies may be formally valid, but still fallacious.^[3]

A special case is a mathematical fallacy, an intentionally invalid mathematical proof with a concealed, or subtle, error. Mathematical fallacies are typically crafted and exhibited for educational purposes, usually taking the form of false proofs of obvious contradictions.^[6]

Overview[edit]

Fallacies are defects that weaken arguments. According to The New Handbook of Cognitive Therapy Techniques, they include «unsubstantiated assertions that are often delivered with a conviction that makes them sound as though they are proven facts.»^[7] Informal fallacies in particular are found frequently in mass media such as television and newspapers.^[8] Understanding fallacies may allow one to recognize them in either one’s own or others’ writing. Avoiding fallacies may help improve one’s ability to produce sound arguments.^[9]

It can be difficult to evaluate whether an argument is fallacious, as arguments exist along a continuum of soundness and an argument that has several stages or parts might have some sound sections and some fallacious ones.^[10] Moreover, whether a specific argument is fallacious often depends on the content rather than the form of the argument. An example is a probabilistically valid instance of the formally invalid argument form of denying the antecedent or affirming the consequent. ^[11] Thus, «[f]allacious arguments usually have the deceptive appearance of being good arguments,» ^[12] because for most fallacious instances of an argument form, a similar but non-fallacious instance can be found. Evaluating an instance of an argument form as fallacious is therefore virtually always also a matter of evaluating the context of the argument.

Recognizing fallacies in everyday arguments may be difficult since arguments are often embedded in rhetorical patterns that obscure the logical connections between statements. Informal fallacies may also exploit the emotional, intellectual, or psychological weaknesses of the audience. Recognizing fallacies can develop reasoning skills to expose the weaker links between premises and conclusions to better discern between what appears to be true and what is true.

Argumentation theory provides a different approach to understanding and classifying fallacies. In the Pragma-dialectical theory, for instance, an argument is regarded as an interactive protocol between individuals who attempt to resolve their disagreement on the merits of a case.^[13] The protocol consists of normative rules of interaction, and violations of these rules are considered to be fallacies, because they frustrate the attempt at resolving the disagreement.

Fallacies are used in place of valid reasoning to communicate a point with the intention to persuade. Examples in the mass media today include but are not limited to propaganda, advertisements, politics, newspaper editorials and opinion-based news shows.^[14]

Systems of classification[edit]

Fallacies are generally classified strictly by either their structure or their content, such as classifying them as formal fallacies or informal fallacies, respectively. The classification of informal fallacies may be subdivided into categories such as linguistic, relevance through omission, relevance through intrusion, and relevance through presumption.^[15] Alternatively, fallacies may be classified by the process by which they occur, such as material fallacies (content), verbal fallacies (linguistic), and again formal fallacies (error in inference). In turn, material fallacies may be placed into the more general category of informal fallacies. Verbal fallacies may be placed in either formal or informal classifications: Compare equivocation, which is a word- or phrase-based ambiguity, to the fallacy of composition, which is premise- and inference-based ambiguity.^[16]

Greek logic[edit]

Greek philosopher Aristotle (384 – 322 BC) was the first to systematize logical errors into a list, to make it easier to refute an opponent’s thesis and thus win an argument.^[17]: 2 Aristotle’s «Sophistical Refutations» (De Sophisticis Elenchis) identifies thirteen fallacies. He divided them up into two major types, linguistic fallacies and non-linguistic fallacies, some which depend on language and others that do not.^[18][19] These fallacies are called verbal fallacies and material fallacies, respectively. A material fallacy is an error in what the arguer is talking about, while a verbal fallacy is an error in how the arguer is talking. Verbal fallacies are those in which a conclusion is obtained by improper or ambiguous use of words.^[20]
An example of a language dependent fallacy is given as a debate as to who in humanity are learners: the wise or the ignorant.^[17]: 3 A language-independent fallacy is for example:

1. «Coriscus is different from Socrates.»
2. «Socrates is a man.»
3. «Therefore, Coriscus is different from a man.»^[17]: 4

Indian logic[edit]

Indian logicians took great pains to identify fallacies in an argument. An influential collection of texts on logic and reason, the Nyāya Sūtras, attributed to Aksapada Gautama, variously estimated to have been composed between 6th-century BCE and 2nd-century CE, in its theory of inference lists five such reasons used in an argument which was further developed by later logicians.^[21][22][23]

1. Asiddha: It is the unproved reason that results in this fallacy. [Paksadharmata]
2. Savyabhichara: This is the fallacy of irregular reason.
3. Satpratipaksa: Here the reason is contradicted by another reason. If both have equal force, then nothing follows. ‘Sound is eternal, because it is audible’, and ‘Sound is non-eternal, because it is produced’. Here ‘audible’ is counterbalanced by ‘produced’ and both are of equal force.
4. Badhita: When another proof (as by perception) definitely contradicts and disproves the middle term (reason). ‘Fire is cold because it is a substance’.
5. Viruddha: Instead of proving something it is proving the opposite. ‘Sound is eternal because it is produced’.

Whately’s grouping[edit]

English scholar and theologian Richard Whately (1787 – 1863) defines a fallacy broadly as, «any argument, or apparent argument, which professes to be decisive of the matter at hand, while in reality it is not».^[17]: 8

Whately divided fallacies into two groups: logical and material. According to Whately, logical fallacies are arguments where the conclusion does not follow from the premises. Material fallacies are not logical errors because the conclusion does follow from the premises. He then divided the logical group into two groups: purely logical and semi-logical. The semi-logical group included all of Aristotle’s sophisms except ignoratio elenchi, petitio principii, and non causa pro causa, which are in the material group.^[24]

Other systems of classification[edit]

Other famous methods of classifying fallacies are those of Francis Bacon and J. S. Mill. Bacon (Novum Organum, Aph. 33, 38 sqq.) divided fallacies into four Idola (Idols, i.e. False Appearances), which summarize the various kinds of mistakes to which the human intellect is prone. J. S. Mill discussed the subject in book five of his Logic, and Jeremy Bentham’s Book of Fallacies (1824) contains valuable remarks.

Formal fallacy[edit]

A formal fallacy, deductive fallacy, logical fallacy or non sequitur (Latin for «it does not follow») is a flaw in the structure of a deductive argument which renders the argument invalid. The flaw can neatly be expressed in standard system of logic.^[1] Such an argument is always considered to be wrong.
The presence of the formal fallacy does not imply anything about the argument’s premises or its conclusion. Both may actually be true, or may even be more probable as a result of the argument, but the deductive argument is still invalid because the conclusion does not follow from the premises in the manner described.

Even non-deductive arguments can be said to be fallacious: for example, an inductive argument that incorrectly applies principles of probability or causality. But «since deductive arguments depend on formal properties and inductive arguments don’t, formal fallacies apply only to deductive arguments.»^[5]

A logical form such as «A and B» is independent of any particular conjunction of meaningful propositions. Logical form alone can guarantee that given true premises, a true conclusion must follow. However, formal logic makes no such guarantee if any premise is false; the conclusion can be either true or false. Any formal error or logical fallacy similarly invalidates the deductive guarantee. Both the argument and all its premises must be true for a conclusion to be true.

The term logical fallacy is in a sense self-contradictory, because logic refers to valid reasoning, whereas a fallacy is the use of poor reasoning. Therefore, the term formal fallacy is preferred. In informal discourse, however, logical fallacy is used to mean an argument which is problematic for any reason.

The term non sequitur denotes a general formal fallacy, often meaning one which does not belong to any named subclass of formal fallacies like affirming the consequent.

Common examples[edit]

Ecological fallacy[edit]

An ecological fallacy is committed when one draws an inference from data based on the premise that qualities observed for groups necessarily hold for individuals; for example, «if countries with more Protestants tend to have higher suicide rates, then Protestants must be more likely to commit suicide.»^[25]

Fallacy fork[edit]

Maarten Boudry^[26] and others^[27] have argued that formal, deductive fallacies rarely occur in real life and that arguments that would be fallacious in formally deductive terms are not necessarily so when context and prior probabilities are taken into account, thus making the argument defeasible and/or inductive. Boudry coined the term fallacy fork.^[26] For a given fallacy, one must either characterize it by means of a deductive argumentation scheme, which rarely applies (the first prong of the fork), or one must relax definitions and add nuance to take the actual intent and context of the argument into account (the other prong of the fork).^[26] To argue, for example, that one became nauseated after eating a mushroom because the mushroom was poisonous could be an example of the post hoc ergo propter hoc fallacy.^[26]

Informal fallacy[edit]

In contrast to a formal fallacy, an informal fallacy originates in a reasoning error other than a flaw in the logical form of the argument.^[5] A deductive argument containing an informal fallacy may be formally valid,^[3] but still remain rationally unpersuasive. Nevertheless, informal fallacies apply to both deductive and non-deductive arguments.

Though the form of the argument may be relevant, fallacies of this type are the «types of mistakes in reasoning that arise from the mishandling of the content of the propositions constituting the argument».^[28]

Faulty generalization[edit]

A special subclass of the informal fallacies is the set of faulty generalizations, also known as inductive fallacies. Here the most important issue concerns inductive strength or methodology (for example, statistical inference). In the absence of sufficient evidence, drawing conclusions based on induction is unwarranted and fallacious. With the backing of sufficient amounts of the right type of empirical evidence, however, the conclusions may become warranted and convincing (at which point the arguments are no longer considered fallacious).^[29]

Hasty generalization[edit]

Hasty generalization is described as making assumptions about a whole group or range of cases based on a sample that is inadequate (usually because it is atypical or just too small).
Stereotypes about people («frat boys are drunkards», «grad students are nerdy», «women don’t enjoy sports», etc.) are common examples of the principle.

Hasty generalization often follows a pattern such as:

X is true for A.

X is true for B.

Therefore, X is true for C, D, etc.

While never a valid logical deduction, if such an inference can be made on statistical grounds, it may nonetheless be convincing. This is because with enough empirical evidence, the generalization is no longer a hasty one.

Relevance fallacy[edit]

The fallacies of relevance are a broad class of informal fallacies, generically represented by missing the point: presenting an argument, which may be sound, but fails to address the issue in question.

Argument from silence[edit]

An argument from silence is a faulty conclusion that is made based on the absence of evidence rather than on the presence of evidence.

Examples of informal fallacies[edit]

Post hoc (false cause)[edit]

The post hoc fallacy assumes that because B comes after A, A caused B. It gets its name from the Latin phrase «post hoc, ergo propter hoc«, which translates as «after this, therefore because of this».

Sometimes one event really does cause another one that comes later—for example, if one registers for a class, and their name later appears on the roll, it’s true that the first event caused the one that came later. But sometimes two events that seem related in time are not really related as cause and event. That is, temporal correlation does not necessarily entail causation. For example, if one eats a sandwich and then gets food poisoning, that does not necessarily mean the sandwich caused the food poisoning. Something else eaten earlier might have caused the food poisoning.

Slippery slope[edit]

For an argument to be a slippery slope type of argument it must meet the requirements of that argumentation scheme. A slippery slope argument originates from a conversation or debate in which two actors take turns. It usually originates from one actor giving advice on a decision or act. Along the way, the actor must make additional choices on similar matters through which the actor enters the ‘grey area’ of the slippery slope. At this point, the actor potentially loses control over the direction of the arguments, thus leading to a ‘fatal’ outcome.^[30]

Such an argument is built up according to the following argumentation scheme: initial premise, sequential premise, indeterminacy premise, control premise, loss of control premise, catastrophic outcome premise and conclusion. Slippery slope arguments may be defeated by asking critical questions or giving counterarguments.^[31]

There are several reasons for a slippery slope to be fallacious: for example, the argument is going too far into the future, it is a too complex argument and its structure is hard to identify or the argument makes emotional appeals.^[32]

Care however has to be taken not to dismiss all aspects of the slippery slope arguments as a fallacy, especially if it can be argued that the projected future outcomes are reasonably probable.^[33]

False analogy[edit]

Informally known as the «apples and oranges» fallacy, a false analogy uses unsound comparisons.^[34]

Straw man fallacy[edit]

The straw man fallacy consists in presenting the standpoint of an opponent as more extreme, distorted or simplistic than it in fact is. Compared to criticizing the opponent’s actual standpoint, this allows the arguer to offer a seeming refutation of what however is not the actual standpoint.^[35] Such an argument involves two arguers, with one actor criticizing the perspective of the other.^[36] The reason for the straw man argument to be fallacious originates from the problem of how to deal with natural discourse. The opponent’s argument is not reflected by the arguments that are proposed by the speaker.^[37]

Measurement fallacy[edit]

Some of the fallacies described above may be committed in the context of measurement.
Where mathematical fallacies are subtle mistakes in reasoning leading to invalid mathematical proofs, measurement fallacies are unwarranted inferential leaps involved in the extrapolation of raw data to a measurement-based value claim. The ancient Greek Sophist Protagoras was one of the first thinkers to propose that humans can generate reliable measurements through his «human-measure» principle and the practice of dissoi logoi (arguing multiple sides of an issue).^[38][39] This history helps explain why measurement fallacies are informed by informal logic and argumentation theory.

Knowledge value measurement fallacy[edit]

The increasing availability and circulation of big data are driving a proliferation of new metrics for scholarly authority,^[40][41] and there is lively discussion regarding the relative usefulness of such metrics for measuring the value of knowledge production in the context of an «information tsunami.»^[42]

For example, anchoring fallacies can occur when unwarranted weight is given to data generated by metrics that the arguers themselves acknowledge are flawed. For example, limitations of the journal impact factor (JIF) are well documented,^[43] and even JIF pioneer Eugene Garfield notes, «while citation data create new tools for analyses of research performance, it should be stressed that they supplement rather than replace other quantitative-and qualitative-indicators.»^[44] To the extent that arguers jettison acknowledged limitations of JIF-generated data in evaluative judgments, or leave behind Garfield’s «supplement rather than replace» caveat, they court commission of anchoring fallacies.

A naturalistic fallacy can occur for example in the case of sheer quantity metrics based on the premise «more is better»^[42] or, in the case of developmental assessment in the field of psychology, «higher is better».^[45]

A false analogy occurs when claims are supported by unsound comparisons between data points. For example, the Scopus and Web of Science bibliographic databases have difficulty distinguishing between citations of scholarly work that are arms-length endorsements, ceremonial citations, or negative citations (indicating the citing author withholds endorsement of the cited work).^[40] Hence, measurement-based value claims premised on the uniform quality of all citations may be questioned on false analogy grounds.

As another example, consider the Faculty Scholarly Productivity Index of Academic Analytics. This tool purports to measure overall faculty productivity, yet it does not capture data based on citations in books. This creates a possibility that low productivity measurements using the tool commit argument from silence fallacies, to the extent that such measurements are supported by the absence of book citation data.

Ecological fallacies can be committed when one measures scholarly productivity of a sub-group of individuals (e.g. «Puerto Rican» faculty) via reference to aggregate data about a larger and different group (e.g. «Hispanic» faculty).^[46]

Intentional fallacy[edit]

Sometimes a speaker or writer uses a fallacy intentionally. In any context, including academic debate, a conversation among friends, political discourse, advertising, or for comedic purposes, the arguer may use fallacious reasoning to try to persuade the listener or reader, by means other than offering relevant evidence, that the conclusion is true.

Examples of this include the speaker or writer:^[47]

1. Diverting the argument to unrelated issues with a red herring (Ignoratio elenchi)
2. Insulting someone’s character (argumentum ad hominem)
3. Assuming the conclusion of an argument, a kind of circular reasoning, also called «begging the question» (petitio principii)
4. Making jumps in logic (non sequitur)
5. Identifying a false cause and effect (post hoc ergo propter hoc)
6. Asserting that everyone agrees (argumentum ad populum, bandwagoning)
7. Creating a false dilemma (either-or fallacy) in which the situation is oversimplified, also called false dichotomy
8. Selectively using facts (card stacking)
9. Making false or misleading comparisons (false equivalence and false analogy)
10. Generalizing quickly and sloppily (hasty generalization)
11. Using an argument’s connections to other concepts or people to support or refute it, also called «guilt by association» (association fallacy)
12. Claiming that a lack of proof counts as proof (appeal to ignorance)

In humor, errors of reasoning are used for comical purposes. Groucho Marx used fallacies of amphiboly, for instance, to make ironic statements; Gary Larson and Scott Adams employed fallacious reasoning in many of their cartoons. Wes Boyer and Samuel Stoddard have written a humorous essay teaching students how to be persuasive by means of a whole host of informal and formal fallacies.^[48]

When someone uses logical fallacies intentionally to mislead in academic, political, or other high-stakes contexts, the breach of trust calls into question the authority and intellectual integrity of that person.^[49]

Assessment: pragmatic theory[edit]

According to the pragmatic theory,^[50] a fallacy can be either a heuristic error or a ploy used intentionally to unfairly win an argument. There are always two parties to an argument containing a fallacy: the perpetrator and the intended victim.

The dialogue framework required to support the pragmatic theory of fallacy is built on the presumption that argumentative dialogue has both an adversarial component and a collaborative component. A dialogue has individual goals for each participant, but also shared goals that apply to all participants. A fallacy of the second kind is seen as more than simply violation of a rule of reasonable dialogue. It is also a deceptive tactic of argumentation, based on sleight-of-hand. Aristotle explicitly compared contentious reasoning to unfair fighting in athletic contest. But the roots of the pragmatic theory go back even further in history to the Sophists. The pragmatic theory finds its roots in the Aristotelian conception of a fallacy as a sophistical refutation, but also supports the view that many of the types of arguments traditionally labeled as fallacies are in fact reasonable techniques of argumentation that can be used, in many cases, to support legitimate goals of dialogue. Hence, under the pragmatic approach, each case needs to be analyzed individually to determine whether the argument is fallacious or reasonable.

See also[edit]

References[edit]

Further reading[edit]

• C. L. Hamblin, Fallacies, Methuen London, 1970. reprinted by Vale Press in 1998. ISBN 0916475247.
• Hans V. Hansen; Robert C. Pinto (1995). Fallacies: classical and contemporary readings. Penn State Press. ISBN 978-0271014173.
• Douglas N. Walton, Informal logic: A handbook for critical argumentation. Cambridge University Press, 1989.^{[ISBN missing]}
• Douglas, Walton (1987). Informal Fallacies. Amsterdam: John Benjamins.^{[ISBN missing]}
• Walton, Douglas (1995). A Pragmatic Theory of Fallacy. Tuscaloosa: University of Alabama Press.^{[ISBN missing]}
• Walton, Douglas (2010). «Why Fallacies Appear to Be Better Arguments than They Are». Informal Logic. 30 (2): 159–184. doi:10.22329/il.v30i2.2868.
• John Woods (2004). The death of argument: fallacies in agent based reasoning. Springer. ISBN 978-1402026638.
• Woods, John (2013). Errors of Reasoning: Naturalizing the Logic of Inference. London: College Publications. ISBN 978-1848901148
• Fearnside, W. Ward and William B. Holther, Fallacy: The Counterfeit of Argument, 1959.^{[ISBN missing]}
• Vincent F. Hendricks, Thought 2 Talk: A Crash Course in Reflection and Expression, New York: Automatic Press / VIP, 2005, ISBN 8799101378
• D. H. Fischer, Historians’ Fallacies: Toward a Logic of Historical Thought, Harper Torchbooks, 1970.^{[ISBN missing]}
• Warburton Nigel, Thinking from A to Z, Routledge 1998.^{[ISBN missing]}
• Sagan, Carl, «The Demon-Haunted World: Science As a Candle in the Dark«. Ballantine Books, 1997 ISBN 0345409469, 480 pgs. 1996 hardback edition: Random House, ISBN 039453512X, xv+457 pages plus addenda insert (some printings). Ch. 12.

Historical texts[edit]

• Aristotle, On Sophistical Refutations, De Sophistici Elenchi. library.adelaide.edu.au
• William of Ockham, Summa of Logic (c. 1323) Part III.4.
• John Buridan, Summulae de dialectica Book VII.
• Francis Bacon, the doctrine of the idols in Novum Organum Scientiarum, Aphorisms concerning The Interpretation of Nature and the Kingdom of Man, xxiii ff Archived 2020-02-14 at the Wayback Machine. fly.hiwaay.net
• Arthur Schopenhauer, The Art of Controversy | Die Kunst, Recht zu behalten – The Art Of Controversy (bilingual), (also known as «Schopenhauers 38 stratagems»). gutenberg.org
• John Stuart Mill, A System of Logic – Raciocinative and Inductive. Book 5, Chapter 7, Fallacies of Confusion. la.utexas.edu

External links[edit]

• Hansen, Hans. «Fallacies». In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
• Zalta, Edward N. (ed.). «Informal logic». Stanford Encyclopedia of Philosophy.
• «Fallacy». Internet Encyclopedia of Philosophy.
• Fallacy at PhilPapers
• Humbug! The skeptic’s field guide to spotting fallacies in thinking – textbook on fallacies. scribd.com
• List of fallacies with clear examples, infidels.org
• Interactive Syllogistic Machine A web based syllogistic machine for exploring fallacies, figures, and modes of syllogisms.
• Logical Fallacies and the Art of Debate, csun.edu
• Stephen Downes Guide to the Logical Fallacies, onegoodmove.org
• Explain fallacies, what they are and how to avoid them
• Fallacy Files
• Chisholm, Hugh, ed. (1911). «Fallacy» . Encyclopædia Britannica. Vol. 10 (11th ed.). Cambridge University Press. pp. 153–154.

A fallacy is the use of invalid or otherwise faulty reasoning in the construction of an argument^[1][2] which may appear to be a well-reasoned argument if unnoticed. The term was introduced in the Western intellectual tradition by the Aristotelian De Sophisticis Elenchis.^[3]

Fallacies may be committed intentionally to manipulate or persuade by deception, unintentionally because of human limitations such as carelessness, cognitive or social biases and ignorance, or potentially due to the limitations of language and understanding of language. These delineations include not only the ignorance of the right reasoning standard, but also the ignorance of relevant properties of the context. For instance, the soundness of legal arguments depends on the context in which the arguments are made.^[4]

Fallacies are commonly divided into «formal» and «informal.» A formal fallacy is a flaw in the structure of a deductive argument which renders the argument invalid, while an informal fallacy originates in an error in reasoning other than an improper logical form.^[5] Arguments containing informal fallacies may be formally valid, but still fallacious.^[3]

A special case is a mathematical fallacy, an intentionally invalid mathematical proof with a concealed, or subtle, error. Mathematical fallacies are typically crafted and exhibited for educational purposes, usually taking the form of false proofs of obvious contradictions.^[6]

Overview[edit]

Fallacies are defects that weaken arguments. According to The New Handbook of Cognitive Therapy Techniques, they include «unsubstantiated assertions that are often delivered with a conviction that makes them sound as though they are proven facts.»^[7] Informal fallacies in particular are found frequently in mass media such as television and newspapers.^[8] Understanding fallacies may allow one to recognize them in either one’s own or others’ writing. Avoiding fallacies may help improve one’s ability to produce sound arguments.^[9]

It can be difficult to evaluate whether an argument is fallacious, as arguments exist along a continuum of soundness and an argument that has several stages or parts might have some sound sections and some fallacious ones.^[10] Moreover, whether a specific argument is fallacious often depends on the content rather than the form of the argument. An example is a probabilistically valid instance of the formally invalid argument form of denying the antecedent or affirming the consequent. ^[11] Thus, «[f]allacious arguments usually have the deceptive appearance of being good arguments,» ^[12] because for most fallacious instances of an argument form, a similar but non-fallacious instance can be found. Evaluating an instance of an argument form as fallacious is therefore virtually always also a matter of evaluating the context of the argument.

Recognizing fallacies in everyday arguments may be difficult since arguments are often embedded in rhetorical patterns that obscure the logical connections between statements. Informal fallacies may also exploit the emotional, intellectual, or psychological weaknesses of the audience. Recognizing fallacies can develop reasoning skills to expose the weaker links between premises and conclusions to better discern between what appears to be true and what is true.

Argumentation theory provides a different approach to understanding and classifying fallacies. In the Pragma-dialectical theory, for instance, an argument is regarded as an interactive protocol between individuals who attempt to resolve their disagreement on the merits of a case.^[13] The protocol consists of normative rules of interaction, and violations of these rules are considered to be fallacies, because they frustrate the attempt at resolving the disagreement.

Fallacies are used in place of valid reasoning to communicate a point with the intention to persuade. Examples in the mass media today include but are not limited to propaganda, advertisements, politics, newspaper editorials and opinion-based news shows.^[14]

Systems of classification[edit]

Fallacies are generally classified strictly by either their structure or their content, such as classifying them as formal fallacies or informal fallacies, respectively. The classification of informal fallacies may be subdivided into categories such as linguistic, relevance through omission, relevance through intrusion, and relevance through presumption.^[15] Alternatively, fallacies may be classified by the process by which they occur, such as material fallacies (content), verbal fallacies (linguistic), and again formal fallacies (error in inference). In turn, material fallacies may be placed into the more general category of informal fallacies. Verbal fallacies may be placed in either formal or informal classifications: Compare equivocation, which is a word- or phrase-based ambiguity, to the fallacy of composition, which is premise- and inference-based ambiguity.^[16]

Greek logic[edit]

Greek philosopher Aristotle (384 – 322 BC) was the first to systematize logical errors into a list, to make it easier to refute an opponent’s thesis and thus win an argument.^[17]: 2 Aristotle’s «Sophistical Refutations» (De Sophisticis Elenchis) identifies thirteen fallacies. He divided them up into two major types, linguistic fallacies and non-linguistic fallacies, some which depend on language and others that do not.^[18][19] These fallacies are called verbal fallacies and material fallacies, respectively. A material fallacy is an error in what the arguer is talking about, while a verbal fallacy is an error in how the arguer is talking. Verbal fallacies are those in which a conclusion is obtained by improper or ambiguous use of words.^[20]
An example of a language dependent fallacy is given as a debate as to who in humanity are learners: the wise or the ignorant.^[17]: 3 A language-independent fallacy is for example:

1. «Coriscus is different from Socrates.»
2. «Socrates is a man.»
3. «Therefore, Coriscus is different from a man.»^[17]: 4

Indian logic[edit]

Indian logicians took great pains to identify fallacies in an argument. An influential collection of texts on logic and reason, the Nyāya Sūtras, attributed to Aksapada Gautama, variously estimated to have been composed between 6th-century BCE and 2nd-century CE, in its theory of inference lists five such reasons used in an argument which was further developed by later logicians.^[21][22][23]

1. Asiddha: It is the unproved reason that results in this fallacy. [Paksadharmata]
2. Savyabhichara: This is the fallacy of irregular reason.
3. Satpratipaksa: Here the reason is contradicted by another reason. If both have equal force, then nothing follows. ‘Sound is eternal, because it is audible’, and ‘Sound is non-eternal, because it is produced’. Here ‘audible’ is counterbalanced by ‘produced’ and both are of equal force.
4. Badhita: When another proof (as by perception) definitely contradicts and disproves the middle term (reason). ‘Fire is cold because it is a substance’.
5. Viruddha: Instead of proving something it is proving the opposite. ‘Sound is eternal because it is produced’.

Whately’s grouping[edit]

English scholar and theologian Richard Whately (1787 – 1863) defines a fallacy broadly as, «any argument, or apparent argument, which professes to be decisive of the matter at hand, while in reality it is not».^[17]: 8

Whately divided fallacies into two groups: logical and material. According to Whately, logical fallacies are arguments where the conclusion does not follow from the premises. Material fallacies are not logical errors because the conclusion does follow from the premises. He then divided the logical group into two groups: purely logical and semi-logical. The semi-logical group included all of Aristotle’s sophisms except ignoratio elenchi, petitio principii, and non causa pro causa, which are in the material group.^[24]

Other systems of classification[edit]

Other famous methods of classifying fallacies are those of Francis Bacon and J. S. Mill. Bacon (Novum Organum, Aph. 33, 38 sqq.) divided fallacies into four Idola (Idols, i.e. False Appearances), which summarize the various kinds of mistakes to which the human intellect is prone. J. S. Mill discussed the subject in book five of his Logic, and Jeremy Bentham’s Book of Fallacies (1824) contains valuable remarks.

Formal fallacy[edit]

A formal fallacy, deductive fallacy, logical fallacy or non sequitur (Latin for «it does not follow») is a flaw in the structure of a deductive argument which renders the argument invalid. The flaw can neatly be expressed in standard system of logic.^[1] Such an argument is always considered to be wrong.
The presence of the formal fallacy does not imply anything about the argument’s premises or its conclusion. Both may actually be true, or may even be more probable as a result of the argument, but the deductive argument is still invalid because the conclusion does not follow from the premises in the manner described.

Even non-deductive arguments can be said to be fallacious: for example, an inductive argument that incorrectly applies principles of probability or causality. But «since deductive arguments depend on formal properties and inductive arguments don’t, formal fallacies apply only to deductive arguments.»^[5]

A logical form such as «A and B» is independent of any particular conjunction of meaningful propositions. Logical form alone can guarantee that given true premises, a true conclusion must follow. However, formal logic makes no such guarantee if any premise is false; the conclusion can be either true or false. Any formal error or logical fallacy similarly invalidates the deductive guarantee. Both the argument and all its premises must be true for a conclusion to be true.

The term logical fallacy is in a sense self-contradictory, because logic refers to valid reasoning, whereas a fallacy is the use of poor reasoning. Therefore, the term formal fallacy is preferred. In informal discourse, however, logical fallacy is used to mean an argument which is problematic for any reason.

The term non sequitur denotes a general formal fallacy, often meaning one which does not belong to any named subclass of formal fallacies like affirming the consequent.

Common examples[edit]

Ecological fallacy[edit]

An ecological fallacy is committed when one draws an inference from data based on the premise that qualities observed for groups necessarily hold for individuals; for example, «if countries with more Protestants tend to have higher suicide rates, then Protestants must be more likely to commit suicide.»^[25]

Fallacy fork[edit]

Maarten Boudry^[26] and others^[27] have argued that formal, deductive fallacies rarely occur in real life and that arguments that would be fallacious in formally deductive terms are not necessarily so when context and prior probabilities are taken into account, thus making the argument defeasible and/or inductive. Boudry coined the term fallacy fork.^[26] For a given fallacy, one must either characterize it by means of a deductive argumentation scheme, which rarely applies (the first prong of the fork), or one must relax definitions and add nuance to take the actual intent and context of the argument into account (the other prong of the fork).^[26] To argue, for example, that one became nauseated after eating a mushroom because the mushroom was poisonous could be an example of the post hoc ergo propter hoc fallacy.^[26]

Informal fallacy[edit]

In contrast to a formal fallacy, an informal fallacy originates in a reasoning error other than a flaw in the logical form of the argument.^[5] A deductive argument containing an informal fallacy may be formally valid,^[3] but still remain rationally unpersuasive. Nevertheless, informal fallacies apply to both deductive and non-deductive arguments.

Though the form of the argument may be relevant, fallacies of this type are the «types of mistakes in reasoning that arise from the mishandling of the content of the propositions constituting the argument».^[28]

Faulty generalization[edit]

A special subclass of the informal fallacies is the set of faulty generalizations, also known as inductive fallacies. Here the most important issue concerns inductive strength or methodology (for example, statistical inference). In the absence of sufficient evidence, drawing conclusions based on induction is unwarranted and fallacious. With the backing of sufficient amounts of the right type of empirical evidence, however, the conclusions may become warranted and convincing (at which point the arguments are no longer considered fallacious).^[29]

Hasty generalization[edit]

Hasty generalization is described as making assumptions about a whole group or range of cases based on a sample that is inadequate (usually because it is atypical or just too small).
Stereotypes about people («frat boys are drunkards», «grad students are nerdy», «women don’t enjoy sports», etc.) are common examples of the principle.

Hasty generalization often follows a pattern such as:

X is true for A.

X is true for B.

Therefore, X is true for C, D, etc.

While never a valid logical deduction, if such an inference can be made on statistical grounds, it may nonetheless be convincing. This is because with enough empirical evidence, the generalization is no longer a hasty one.

Relevance fallacy[edit]

The fallacies of relevance are a broad class of informal fallacies, generically represented by missing the point: presenting an argument, which may be sound, but fails to address the issue in question.

Argument from silence[edit]

An argument from silence is a faulty conclusion that is made based on the absence of evidence rather than on the presence of evidence.

Examples of informal fallacies[edit]

Post hoc (false cause)[edit]

The post hoc fallacy assumes that because B comes after A, A caused B. It gets its name from the Latin phrase «post hoc, ergo propter hoc«, which translates as «after this, therefore because of this».

Sometimes one event really does cause another one that comes later—for example, if one registers for a class, and their name later appears on the roll, it’s true that the first event caused the one that came later. But sometimes two events that seem related in time are not really related as cause and event. That is, temporal correlation does not necessarily entail causation. For example, if one eats a sandwich and then gets food poisoning, that does not necessarily mean the sandwich caused the food poisoning. Something else eaten earlier might have caused the food poisoning.

Slippery slope[edit]

For an argument to be a slippery slope type of argument it must meet the requirements of that argumentation scheme. A slippery slope argument originates from a conversation or debate in which two actors take turns. It usually originates from one actor giving advice on a decision or act. Along the way, the actor must make additional choices on similar matters through which the actor enters the ‘grey area’ of the slippery slope. At this point, the actor potentially loses control over the direction of the arguments, thus leading to a ‘fatal’ outcome.^[30]

Such an argument is built up according to the following argumentation scheme: initial premise, sequential premise, indeterminacy premise, control premise, loss of control premise, catastrophic outcome premise and conclusion. Slippery slope arguments may be defeated by asking critical questions or giving counterarguments.^[31]

There are several reasons for a slippery slope to be fallacious: for example, the argument is going too far into the future, it is a too complex argument and its structure is hard to identify or the argument makes emotional appeals.^[32]

Care however has to be taken not to dismiss all aspects of the slippery slope arguments as a fallacy, especially if it can be argued that the projected future outcomes are reasonably probable.^[33]

False analogy[edit]

Informally known as the «apples and oranges» fallacy, a false analogy uses unsound comparisons.^[34]

Straw man fallacy[edit]

The straw man fallacy consists in presenting the standpoint of an opponent as more extreme, distorted or simplistic than it in fact is. Compared to criticizing the opponent’s actual standpoint, this allows the arguer to offer a seeming refutation of what however is not the actual standpoint.^[35] Such an argument involves two arguers, with one actor criticizing the perspective of the other.^[36] The reason for the straw man argument to be fallacious originates from the problem of how to deal with natural discourse. The opponent’s argument is not reflected by the arguments that are proposed by the speaker.^[37]

Measurement fallacy[edit]

Some of the fallacies described above may be committed in the context of measurement.
Where mathematical fallacies are subtle mistakes in reasoning leading to invalid mathematical proofs, measurement fallacies are unwarranted inferential leaps involved in the extrapolation of raw data to a measurement-based value claim. The ancient Greek Sophist Protagoras was one of the first thinkers to propose that humans can generate reliable measurements through his «human-measure» principle and the practice of dissoi logoi (arguing multiple sides of an issue).^[38][39] This history helps explain why measurement fallacies are informed by informal logic and argumentation theory.

Knowledge value measurement fallacy[edit]

The increasing availability and circulation of big data are driving a proliferation of new metrics for scholarly authority,^[40][41] and there is lively discussion regarding the relative usefulness of such metrics for measuring the value of knowledge production in the context of an «information tsunami.»^[42]

For example, anchoring fallacies can occur when unwarranted weight is given to data generated by metrics that the arguers themselves acknowledge are flawed. For example, limitations of the journal impact factor (JIF) are well documented,^[43] and even JIF pioneer Eugene Garfield notes, «while citation data create new tools for analyses of research performance, it should be stressed that they supplement rather than replace other quantitative-and qualitative-indicators.»^[44] To the extent that arguers jettison acknowledged limitations of JIF-generated data in evaluative judgments, or leave behind Garfield’s «supplement rather than replace» caveat, they court commission of anchoring fallacies.

A naturalistic fallacy can occur for example in the case of sheer quantity metrics based on the premise «more is better»^[42] or, in the case of developmental assessment in the field of psychology, «higher is better».^[45]

A false analogy occurs when claims are supported by unsound comparisons between data points. For example, the Scopus and Web of Science bibliographic databases have difficulty distinguishing between citations of scholarly work that are arms-length endorsements, ceremonial citations, or negative citations (indicating the citing author withholds endorsement of the cited work).^[40] Hence, measurement-based value claims premised on the uniform quality of all citations may be questioned on false analogy grounds.

As another example, consider the Faculty Scholarly Productivity Index of Academic Analytics. This tool purports to measure overall faculty productivity, yet it does not capture data based on citations in books. This creates a possibility that low productivity measurements using the tool commit argument from silence fallacies, to the extent that such measurements are supported by the absence of book citation data.

Ecological fallacies can be committed when one measures scholarly productivity of a sub-group of individuals (e.g. «Puerto Rican» faculty) via reference to aggregate data about a larger and different group (e.g. «Hispanic» faculty).^[46]

Intentional fallacy[edit]

Sometimes a speaker or writer uses a fallacy intentionally. In any context, including academic debate, a conversation among friends, political discourse, advertising, or for comedic purposes, the arguer may use fallacious reasoning to try to persuade the listener or reader, by means other than offering relevant evidence, that the conclusion is true.

Examples of this include the speaker or writer:^[47]

1. Diverting the argument to unrelated issues with a red herring (Ignoratio elenchi)
2. Insulting someone’s character (argumentum ad hominem)
3. Assuming the conclusion of an argument, a kind of circular reasoning, also called «begging the question» (petitio principii)
4. Making jumps in logic (non sequitur)
5. Identifying a false cause and effect (post hoc ergo propter hoc)
6. Asserting that everyone agrees (argumentum ad populum, bandwagoning)
7. Creating a false dilemma (either-or fallacy) in which the situation is oversimplified, also called false dichotomy
8. Selectively using facts (card stacking)
9. Making false or misleading comparisons (false equivalence and false analogy)
10. Generalizing quickly and sloppily (hasty generalization)
11. Using an argument’s connections to other concepts or people to support or refute it, also called «guilt by association» (association fallacy)
12. Claiming that a lack of proof counts as proof (appeal to ignorance)

In humor, errors of reasoning are used for comical purposes. Groucho Marx used fallacies of amphiboly, for instance, to make ironic statements; Gary Larson and Scott Adams employed fallacious reasoning in many of their cartoons. Wes Boyer and Samuel Stoddard have written a humorous essay teaching students how to be persuasive by means of a whole host of informal and formal fallacies.^[48]

When someone uses logical fallacies intentionally to mislead in academic, political, or other high-stakes contexts, the breach of trust calls into question the authority and intellectual integrity of that person.^[49]

Assessment: pragmatic theory[edit]

According to the pragmatic theory,^[50] a fallacy can be either a heuristic error or a ploy used intentionally to unfairly win an argument. There are always two parties to an argument containing a fallacy: the perpetrator and the intended victim.

The dialogue framework required to support the pragmatic theory of fallacy is built on the presumption that argumentative dialogue has both an adversarial component and a collaborative component. A dialogue has individual goals for each participant, but also shared goals that apply to all participants. A fallacy of the second kind is seen as more than simply violation of a rule of reasonable dialogue. It is also a deceptive tactic of argumentation, based on sleight-of-hand. Aristotle explicitly compared contentious reasoning to unfair fighting in athletic contest. But the roots of the pragmatic theory go back even further in history to the Sophists. The pragmatic theory finds its roots in the Aristotelian conception of a fallacy as a sophistical refutation, but also supports the view that many of the types of arguments traditionally labeled as fallacies are in fact reasonable techniques of argumentation that can be used, in many cases, to support legitimate goals of dialogue. Hence, under the pragmatic approach, each case needs to be analyzed individually to determine whether the argument is fallacious or reasonable.

See also[edit]

References[edit]

Further reading[edit]

• C. L. Hamblin, Fallacies, Methuen London, 1970. reprinted by Vale Press in 1998. ISBN 0916475247.
• Hans V. Hansen; Robert C. Pinto (1995). Fallacies: classical and contemporary readings. Penn State Press. ISBN 978-0271014173.
• Douglas N. Walton, Informal logic: A handbook for critical argumentation. Cambridge University Press, 1989.^{[ISBN missing]}
• Douglas, Walton (1987). Informal Fallacies. Amsterdam: John Benjamins.^{[ISBN missing]}
• Walton, Douglas (1995). A Pragmatic Theory of Fallacy. Tuscaloosa: University of Alabama Press.^{[ISBN missing]}
• Walton, Douglas (2010). «Why Fallacies Appear to Be Better Arguments than They Are». Informal Logic. 30 (2): 159–184. doi:10.22329/il.v30i2.2868.
• John Woods (2004). The death of argument: fallacies in agent based reasoning. Springer. ISBN 978-1402026638.
• Woods, John (2013). Errors of Reasoning: Naturalizing the Logic of Inference. London: College Publications. ISBN 978-1848901148
• Fearnside, W. Ward and William B. Holther, Fallacy: The Counterfeit of Argument, 1959.^{[ISBN missing]}
• Vincent F. Hendricks, Thought 2 Talk: A Crash Course in Reflection and Expression, New York: Automatic Press / VIP, 2005, ISBN 8799101378
• D. H. Fischer, Historians’ Fallacies: Toward a Logic of Historical Thought, Harper Torchbooks, 1970.^{[ISBN missing]}
• Warburton Nigel, Thinking from A to Z, Routledge 1998.^{[ISBN missing]}
• Sagan, Carl, «The Demon-Haunted World: Science As a Candle in the Dark«. Ballantine Books, 1997 ISBN 0345409469, 480 pgs. 1996 hardback edition: Random House, ISBN 039453512X, xv+457 pages plus addenda insert (some printings). Ch. 12.

Historical texts[edit]

• Aristotle, On Sophistical Refutations, De Sophistici Elenchi. library.adelaide.edu.au
• William of Ockham, Summa of Logic (c. 1323) Part III.4.
• John Buridan, Summulae de dialectica Book VII.
• Francis Bacon, the doctrine of the idols in Novum Organum Scientiarum, Aphorisms concerning The Interpretation of Nature and the Kingdom of Man, xxiii ff Archived 2020-02-14 at the Wayback Machine. fly.hiwaay.net
• Arthur Schopenhauer, The Art of Controversy | Die Kunst, Recht zu behalten – The Art Of Controversy (bilingual), (also known as «Schopenhauers 38 stratagems»). gutenberg.org
• John Stuart Mill, A System of Logic – Raciocinative and Inductive. Book 5, Chapter 7, Fallacies of Confusion. la.utexas.edu

External links[edit]

• Hansen, Hans. «Fallacies». In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
• Zalta, Edward N. (ed.). «Informal logic». Stanford Encyclopedia of Philosophy.
• «Fallacy». Internet Encyclopedia of Philosophy.
• Fallacy at PhilPapers
• Humbug! The skeptic’s field guide to spotting fallacies in thinking – textbook on fallacies. scribd.com
• List of fallacies with clear examples, infidels.org
• Interactive Syllogistic Machine A web based syllogistic machine for exploring fallacies, figures, and modes of syllogisms.
• Logical Fallacies and the Art of Debate, csun.edu
• Stephen Downes Guide to the Logical Fallacies, onegoodmove.org
• Explain fallacies, what they are and how to avoid them
• Fallacy Files
• Chisholm, Hugh, ed. (1911). «Fallacy» . Encyclopædia Britannica. Vol. 10 (11th ed.). Cambridge University Press. pp. 153–154.

В логике, философии и пр. науках, изучающих познание логическая уловка (англ. logical fallacy) — заведомо ошибочный способ обоснования тезиса, который в силу учёта психологических особенностей собеседника обладает убеждающим воздействием. Ошибочность обусловлена каким-либо логическим недочётом в доказательстве, что делает доказательство в целом неверным.

Виды логических ошибок

Эквивокация

Эквивокация — ошибка, заключающаяся в использовании одного и того же слова в разных значениях в одном рассуждении. Основана на омонимии (от греч. homos — одинаковый и onyma — имя) — свойстве языковых единиц иметь несколько значений или выражать несколько понятий, никак не связанных между собой; напр., слово лук -растение и лук-ручное оружие. Аналогичным термином является Полисемия.

Сообщение об этой логической уловке можно выразить русской поговоркой «Федот, да не тот».

Имеется специальная Категория:Многозначные термины

Подмена слов, тезиса

Подмена Тезиса — (лат. ignoratio elenchi) — логическая ошибка в доказательстве, состоящая в том, что начав доказывать некоторый тезис, постепенно в ходе доказательства переходят к доказательству другого положения, сходного с тезисом.

Логическая уловка отражена в русской поговорке «Я ему про Фому, а он мне про Ерёму».

Использование ложных и недоказанных аргументов, утверждений

Другая логическая ошибка — «предвосхищение основания» (petitio principii). Она заключается в том, что в качестве аргументов используются недоказанные, как правило, произвольно взятые положения: ссылаются на слухи, на ходячие мнения или высказанные кем-то предположения и выдают их за аргументы, якобы обосновывающие основной тезис. В действительности же доброкачественность таких доводов лишь предвосхищается, но не устанавливается с несомненностью.

Обычно подобные лже-аргументы сопровождаются фразами: «Как абсолютно всем известно…», «Кто же будет спорить с тем, что…», «Аксиомой, не требующей доказательств, является то, что…», «Само собой разумеется, что…», «Каждому известо, что…», дабы рассеять возможные сомнения у простого слушателя.

Мнимая логическая связь

Логическая уловка, при которой мнимая, желаемая логическая связь выдаётся за истинную.

Логическая уловка выражена русской поговоркой: «В огороде — бузина, а в Киеве — дядька»

После не значит «вследствие»

Логическая уловка, при которой отождествляется хронологическая, временная связь с причинно-следственной.

Приписывание неделанных утверждений

Логическая ошибка, которая заключается в приписывании одной стороной другой, утверждений, которые на самом деле другая сторона не делала, но которые, якобы вытекают из её предыдущих утверждений.

См. также

• Софизм
• Список парадоксов
• Проблема курицы и яйца
• Сепульки
• Омоним
• Полисемия
• Синонимы
• Полемика
• Риторика
• Прокруст
• Мышление
• Некритичность
• Догматизм

Ссылки

• Теория Аргументации
• Аристотель. Первая аналитика