In logic

Logic

In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

 and rhetoric

Rhetoric

Rhetoric is the art of discourse, an art that aims to improve the facility of speakers or writers who attempt to inform, persuade, or motivate particular audiences in specific situations. As a subject of formal study and a productive civic practice, rhetoric has played a central role in the Western...

, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor (appeal to emotion

Appeal to emotion

Appeal to emotion is a potential fallacy which uses the manipulation of the recipient's emotions, rather than valid logic, to win an argument. The appeal to emotion fallacy uses emotions as the basis of an argument's position without factual evidence that logically supports the major ideas endorsed...

), or take advantage of social relationships between people (e.g. argument from authority

Argument from authority

Argument from authority is a special type of inductive argument which often takes the form of a statistical syllogism....

). Fallacious arguments are often structured using rhetorical patterns that obscure any logical argument.

Fallacies can be used to win arguments regardless of the merits. Among such devices, discussed in more detail below, are: "ignoring the question" to divert argument to unrelated issues using a red herring, making the argument personal (argumentum ad hominem) and discrediting the opposition's character, "begging the question" (petito principi), the use of the non-sequitor, false cause and effect (post hoc ergo propter hoc), bandwagoning (everyone says so), the "false dilemma" or "either-or fallacy" in which the situation is oversimplified, "card-stacking" or selective use of facts, and "false analogy". Another favorite device is the "false generalization", an abstraction of the argument that shifts discussion to platitudes where the facts of the matter are lost. There are many, many more tricks to divert attention from careful exploration of a subject.

Fallacies can generally be classified as informal

Informal fallacy

An informal fallacy is an argument whose stated premises fail to support their proposed conclusion. The deviation in an informal fallacy often stems from a flaw in the path of reasoning that links the premises to the conclusion...

 (premises fail to support the proposed conclusion, but the argument is structured properly) or formal

Formal fallacy

In philosophy, a formal fallacy is a pattern of reasoning that is always wrong. This is due to a flaw in the logical structure of the argument which renders the argument invalid...

 (logical structure is flawed).

Material Fallacies

The taxonomy of material fallacies is based on that of Aristotle

Aristotle

Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

's body structure Organon

Organon

The Organon is the name given by Aristotle's followers, the Peripatetics, to the standard collection of his six works on logic:* Categories* On Interpretation* Prior Analytics* Posterior Analytics...

 (Sophistici elenchi). This taxonomy is as follows:

Fallacy of accident or sweeping generalization

Accident (fallacy)

The logical fallacy of accident is a deductive fallacy occurring in statistical syllogisms when an exception to a rule of thumb is ignored. It is one of the thirteen fallacies originally identified by Aristotle...

• Fallacy of accident or sweeping generalization
  Accident (fallacy)
  The logical fallacy of accident is a deductive fallacy occurring in statistical syllogisms when an exception to a rule of thumb is ignored. It is one of the thirteen fallacies originally identified by Aristotle...
  
  : a generalization that disregards exceptions.
  • Example

    Argument: Cutting people is a crime. Surgeons cut people, therefore, surgeons are criminals.

    Problem: Cutting people is only sometimes a crime.

    Argument: It is illegal for a stranger to enter someone's home uninvited. Firefighters enter people's homes uninvited, therefore firefighters are breaking the law.

    Problem: The exception does not break nor define the rule; a dicto simpliciter ad dictum secundum quid (where an accountable exception is ignored).

Converse fallacy of accident or hasty generalization

Converse accident

The logical fallacy of converse accident is a deductive fallacy that can occur in a statistical syllogism when an exception to a generalization is wrongly called for.For example:The inductive version of this fallacy is called hasty generalization...

• Converse fallacy of accident or hasty generalization
  Converse accident
  The logical fallacy of converse accident is a deductive fallacy that can occur in a statistical syllogism when an exception to a generalization is wrongly called for.For example:The inductive version of this fallacy is called hasty generalization...
  
  : argues from a special case to a general rule.
  • Example

    Argument: Every person I've met speaks English, so it must be true that all people speak English.

    Problem: Those who have been met are a representative subset of the entire set.

  • Also called reverse accident, destroying the exception, a dicto secundum quid ad dictum simpliciter

Irrelevant conclusion

Ignoratio elenchi

Ignoratio elenchi is the informal fallacy of presenting an argument that may in itself be valid, but does not address the issue in question...

• Irrelevant conclusion
  Ignoratio elenchi
  Ignoratio elenchi is the informal fallacy of presenting an argument that may in itself be valid, but does not address the issue in question...
  
  : diverts attention away from a fact in dispute rather than addressing it directly.
  • Example

    Argument: Billy believes that war is justifiable, therefore it must be justifiable.

    Problem: Billy can be wrong. (In particular this is an appeal to authority.)

  • Special cases:
    • purely personal considerations (argumentum ad hominem
      Ad hominem
      An ad hominem , short for argumentum ad hominem, is an attempt to negate the truth of a claim by pointing out a negative characteristic or belief of the person supporting it...
      
      ),
    • popular sentiment (argumentum ad populum—appeal to the majority; appeal to loyalty
      Appeal to loyalty
      The appeal to loyalty is a logical fallacy committed when the premise of an argument uses a perceived need for loyalty of some sort to distract from the issue being discussed.Example:...
      
      .),
    • fear (argumentum ad baculum
      Argumentum ad baculum
      Argumentum ad baculum , also known as appeal to force, is an argument where force, coercion, or the threat of force, is given as a justification for a conclusion...
      
      ),
    • conventional propriety (argumentum ad verecundiam—appeal to authority)
    • to arouse pity for getting one's conclusion accepted (argumentum ad misericordiam
      Appeal to pity
      An appeal to pity is a fallacy in which someone tries to win support for an argument or idea by exploiting his or her opponent's feelings of pity or guilt. It is a specific kind of appeal to emotion....
      
      )
    • forwarding the proposition under dispute without any certain proof (argumentum ad ignorantiam)
    • assuming a perceived defect in the origin of a claim discredits the claim itself (genetic fallacy
      Genetic fallacy
      The genetic fallacy is a fallacy of irrelevance where a conclusion is suggested based solely on something or someone's origin 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...
      
      )
  • Also called Ignoratio Elenchi
    Ignoratio elenchi
    Ignoratio elenchi is the informal fallacy of presenting an argument that may in itself be valid, but does not address the issue in question...
    
    , a "red herring
    Red herring
    A red herring is a deliberate attempt to divert attention.Red herring may refer to:* Red herring , the informal fallacy of presenting an argument that may in itself be valid, but does not address the issue in question....
    
    "

Affirming the consequent

Affirming the consequent

Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:#If P, then Q.#Q.#Therefore, P....

• Affirming the consequent
  Affirming the consequent
  Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:#If P, then Q.#Q.#Therefore, P....
  
  : draws a conclusion from premises that do not support that conclusion by confusing necessary and sufficient conditions.
  • Example:

    Argument: If people have the flu, they cough. Torres is coughing. Therefore, Torres has the flu.

    Problem: Other things, such as asthma, can cause someone to cough. The argument treats having the flu as a necessary condition of coughing; in fact, having the flu is a sufficient condition of coughing, but it is not necessary to have the flu for one to cough.

    Argument: If it rains, the ground gets wet. The ground is wet, therefore it rained.

    Problem: There are other ways by which the ground could get wet (e.g. someone spilled water).

Denying the antecedent

Denying the antecedent

Denying the antecedent, sometimes also called inverse error, is a formal fallacy, committed by reasoning in the form:The name denying the antecedent derives from the premise "not P", which denies the "if" clause of the conditional premise....

• Denying the antecedent
  Denying the antecedent
  Denying the antecedent, sometimes also called inverse error, is a formal fallacy, committed by reasoning in the form:The name denying the antecedent derives from the premise "not P", which denies the "if" clause of the conditional premise....
  
  : draws a conclusion from premises that do not support that conclusion by confusing necessary and sufficient conditions.
  • Example

    Argument: If it is raining outside, it must be cloudy. It is not raining outside. Therefore, it is not cloudy.

    Problem: There does not have to be rain in order for there to be clouds. Rain is a sufficient condition of cloudiness, but it is not necessarily true that clouds mean it is raining.

Begging the question

Begging the question

Begging the question is a type of logical fallacy in which the proposition to be proven is assumed implicitly or explicitly in the premise....

• Begging the question
  Begging the question
  Begging the question is a type of logical fallacy in which the proposition to be proven is assumed implicitly or explicitly in the premise....
  
  : demonstrates a conclusion by means of premises that assume that conclusion.
  • Example

    Argument: Billy always tells the truth, I know this because he told me so.

    Problem: Billy may be lying.

  • Also called Petitio Principii, Circulus in Probando, arguing in a circle, assuming the answer. Begging the question does not preclude the possibility that the statement is incorrect, and it is not sufficient proof in and of itself.

Fallacy of false cause

Non sequitur (logic)

Non sequitur , in formal logic, is an argument in which its conclusion does not follow from its premises. In a non sequitur, the conclusion could be either true or false, but the argument is fallacious because there is a disconnection between the premise and the conclusion. All formal fallacies...

• Fallacy of false cause
  Non sequitur (logic)
  Non sequitur , in formal logic, is an argument in which its conclusion does not follow from its premises. In a non sequitur, the conclusion could be either true or false, but the argument is fallacious because there is a disconnection between the premise and the conclusion. All formal fallacies...
  
   or non sequitur
  Non sequitur (logic)
  Non sequitur , in formal logic, is an argument in which its conclusion does not follow from its premises. In a non sequitur, the conclusion could be either true or false, but the argument is fallacious because there is a disconnection between the premise and the conclusion. All formal fallacies...
  
  : incorrectly assumes one thing is the cause of another. Non Sequitur is Latin for "It does not follow."
  • Example

    Argument: I hear the rain falling outside my window; therefore, the sun is not shining.

    Problem: The conclusion is false because the sun can shine while it is raining

    Sunshower

    A sunshower or sun shower is a meteorological phenomenon in which rain falls while the sun is shining. These conditions often lead to the appearance of a rainbow, if the sun is at a low enough angle. Although used in the United States, Canada, Australia, New Zealand, Ireland, and parts of Britain,...

    
    .

  • Special cases
    • post hoc ergo propter hoc
      Post hoc ergo propter hoc
      Post hoc ergo propter hoc, Latin for "after this, therefore because of this," is a logical fallacy that states, "Since that event followed this one, that event must have been caused by this one." It is often shortened to simply post hoc and is also sometimes referred to as false cause,...
      
      : believing that temporal succession implies a causal relation.
      • Example

        Argument: After Billy was vaccinated he developed autism, therefore the vaccine caused his autism.

        Problem: This does not provide any evidence that the vaccine was the cause. The characteristics of autism may generally become noticeable at the age just following the typical age children receive vaccinations.

    • cum hoc ergo propter hoc: believing that correlation implies a causal relation.
      • Example

        Argument: More cows die in India in the summer months. More ice cream is consumed in summer months. Therefore, the consumption of ice cream in the summer months is killing Indian cows.

        Problem: No premise suggests the ice cream consumption is causing the deaths. The deaths and consumption could be unrelated, or something else could be causing both, such as summer heat.

        Also called causation

        Causation

        Causation may refer to:* Causation , a key component to establish liability in both criminal and civil law* Causation in English law defines the requirement for liability in negligence...

        
         versus correlation

        Correlation

        In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....

        
        .

Fallacy of many questions

Fallacy of many questions

A loaded question is a question which contains a controversial assumption such as a presumption of guilt.Such questions are used rhetorically, so that the question limits direct replies to be those that serve the questioner's agenda...

• Fallacy of many questions
  Fallacy of many questions
  A loaded question is a question which contains a controversial assumption such as a presumption of guilt.Such questions are used rhetorically, so that the question limits direct replies to be those that serve the questioner's agenda...
  
   or loaded question: groups more than one question in the form of a single question.
  • Example

    Argument: Have you stopped beating your wife?

    Problem: A yes or no answer will still be an admission of guilt to beating your wife at some point. (See also Mu.)

  • Also called Plurium Interrogationum
    Complex question
    Complex question, trick question, multiple question or plurium interrogationum is a question that has a presupposition that is complex. The presupposition is a proposition that is presumed to be acceptable to the respondent when the question is asked. The respondent becomes committed to this...
    
    and other terms

Straw man

Straw man

A straw man is a component of an argument and is an informal fallacy based on misrepresentation of an opponent's position, twisting his words or by means of [false] assumptions...

• Straw man
  Straw man
  A straw man is a component of an argument and is an informal fallacy based on misrepresentation of an opponent's position, twisting his words or by means of [false] assumptions...
  
  : A straw man argument is an informal fallacy based on misrepresentation of an opponent's position.
  • Example

    Person A: Sunny days are good.

    Person B: If all days were sunny, we'd never have rain, and without rain, we'd have famine and death. Therefore, you are wrong.

    Problem: B has misrepresented A's claim by falsely suggesting that A claimed that only sunny days are good, and then B refuted the misrepresented version of the claim, rather than refuting A's original assertion.

Same Team Fallacy

• Same Team Fallacy: A case where an arguer knows the main criticisms of their argument, and then asserts that the counter argument should have the same criticisms (based on a genetic fallacy
  Genetic fallacy
  The genetic fallacy is a fallacy of irrelevance where a conclusion is suggested based solely on something or someone's origin 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...
  
   of its arguer). It is often characterized by the fallacy of dismissal after the distinctions and differences are brought out, and the fallacy of repetition thereafter.
  • Example

    Argument I: Skeptics are as religious as any theist, and have just as much faith as well.

    Argument II: Science is just as dogmatic and religious as any other religious institution.

    Conclusion: Skeptics believe through faith, and science is a religion.

    Problem: The member being asked (skeptics, science) to join the team (religion) is not a member by induced fallacies such as conflation

    Conflation

    Conflation occurs when the identities of two or more individuals, concepts, or places, sharing some characteristics of one another, become confused until there seems to be only a single identity — the differences appear to become lost...

    
    , equivocation

    Equivocation

    Equivocation is classified as both a formal and informal logical fallacy. It is the misleading use of a term with more than one meaning or sense...

    
    , spurious similarity, or bad analogy.

    Simplified: Ice cream and shampoo are the same, they both have egg as an ingredient.

(Note in the simplified version the absence of the genetic fallacy

Genetic fallacy

The genetic fallacy is a fallacy of irrelevance where a conclusion is suggested based solely on something or someone's origin 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...

, exposing the basic fault of the argument.)

Verbal Fallacies

Verbal fallacies are those in which a conclusion is obtained by improper or ambiguous use of words. They are generally classified as follows.

Equivocation

Equivocation

Equivocation is classified as both a formal and informal logical fallacy. It is the misleading use of a term with more than one meaning or sense...

• Equivocation
  Equivocation
  Equivocation is classified as both a formal and informal logical fallacy. It is the misleading use of a term with more than one meaning or sense...
  
   consists in employing the same word in two or more senses, e.g. in a syllogism
  Syllogism
  A syllogism is a kind of logical argument in which one proposition is inferred from two or more others of a certain form...
  
  , the middle term being used in one sense in the major and another in the minor premise, so that in fact there are four not three terms.

Example Argument: All heavy things have a great mass; Jim has a "heavy heart"; therefore Jim's heart has a great mass.

Problem: Heavy describes more than just weight. (Jim is sad.)

Connotation fallacies

• Connotation fallacies occur when a dysphemistic
  Dysphemism
  In language, dysphemism, malphemism, and cacophemism refer to the usage of an intentionally harsh, rather than polite, word or expression; roughly the opposite of euphemism...
  
   word is substituted for the speaker's actual quote and used to discredit the argument. It is a form of attribution fallacy
  False attribution
  The fallacy of a false attribution occurs when an advocate appeals to an irrelevant, unqualified, unidentified, biased or fabricated source in support of an argument...
  
  .

Apophasis

Apophasis

Apophasis refers, in general, to "mention by not mentioning". Apophasis covers a wide variety of figures of speech.-Apophasis:...

 and argument by innuendo

• Argument by innuendo
  Innuendo
  An innuendo is a baseless invention of thoughts or ideas. It can also be a remark or question, typically disparaging , that works obliquely by allusion...
  
   involves implicitly suggesting a conclusion without stating it outright. For example, a job reference that says a former employee "was never caught taking money from the cash box" In this example the overly specific nature of the innuendo implies that the employee was a thief, even though it does not make (or justify) a direct negative statement.

Amphiboly

• Amphiboly is the result of ambiguity of grammatical structure.

Example: The position of the adverb "only" in a sentence starting with "He only said that" results in a sentence in which it is uncertain as to which of the other three words the speaker is intending to modify with the adverb.

Fallacy of composition

Fallacy of composition

The fallacy of composition arises when one infers that something is true of the whole from the fact that it is true of some part of the whole...

• Fallacy of composition
  Fallacy of composition
  The fallacy of composition arises when one infers that something is true of the whole from the fact that it is true of some part of the whole...
  
   "From each to all". Arguing from some property of constituent parts, to the conclusion that the composite item has that property. This can be acceptable (i.e., not a fallacy) with certain arguments such as spatial arguments (e.g. "all the parts of the car are in the garage, therefore the car is in the garage").

Example Argument: All the musicians in a band (constituent parts) are highly skilled, therefore the band itself (composite item) is highly skilled.

Problem: The band members may be skilled musicians but lack the ability to function properly as a group.

Division

Fallacy of division

A fallacy of division occurs when one reasons logically that something true of a thing must also be true of all or some of its parts.An example:# A Boeing 747 can fly unaided across the ocean.# A Boeing 747 has jet engines....

• Division
  Fallacy of division
  A fallacy of division occurs when one reasons logically that something true of a thing must also be true of all or some of its parts.An example:# A Boeing 747 can fly unaided across the ocean.# A Boeing 747 has jet engines....
  
  , the converse of the preceding, arguing from a property of the whole, to each constituent part.

Example Argument: "The university (the whole) is 700 years old, therefore, all the staff (each part) are 700 years old".

Problem: Each and every person currently on staff is younger than 700 years. The university continues to exist even when, one by one, each and every person on the original staff leaves and is replaced by a younger person. See Theseus' Ship paradox.

Example Argument: "This cereal is part of a nutritious breakfast therefore the cereal is nutritious."

Problem: Simply because the breakfast taken as a whole is nutritious does not necessarily mean that each part of that breakfast is nutritious.

Proof by verbosity

• Proof by verbosity, sometimes colloquially referred to as argumentum verbosum - a rhetorical technique that tries to persuade by overwhelming those considering an argument with such a volume of material that the argument sounds plausible, superficially appears to be well-researched, and it is so laborious to untangle and check supporting facts that the argument might be allowed to slide by unchallenged.

Accent

• Accent, which occurs only in speaking and consists of emphasizing the wrong word in a sentence. e.g., "He is a fairly good pianist", according to the emphasis on the words, may imply praise of a beginner's progress or insult of an expert pianist.

• "He is a fairly good pianist." This argument places emphasis on the fact that "He", as opposed to anyone else, is a fairly good pianist.
• "He is a fairly good pianist." This is an assertion that he "is" a good pianist, as opposed to a poor one.
• "He is a fairly good pianist." This is an assertion that his ability as a pianist is fair, perhaps in need of improvement.
• "He is a fairly good pianist." This is isolating his ability as only being good in the field of musical instruments, namely, the piano, and possibly excludes the idea that he is good at anything else.
• "I killed my wife?" in response to a police officer asking if he killed his wife. In court, the police officer states his reply to his question was "I killed my wife."

Figure of Speech

• Figure of Speech, the confusion between the metaphorical and ordinary uses of a word or phrase.

Example: The sailor was at home on the sea.

Problem: The expression 'to be at home' does not literally mean that one's domicile is in that location.

Fallacy of misplaced concreteness

• Fallacy of misplaced concreteness, identified by Whitehead in his discussion of metaphysics, this refers to the reification
  Reification (fallacy)
  Reification is a fallacy of ambiguity, when an abstraction 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...
  
   of concepts which exist only in discussion.

Example 1

Timmy argues:

1. Billy is a good tennis player.
2. Therefore, Billy is 'good', that is to say a morally good person.

Here the problem is that the word good has different meanings, which is to say that it is an ambiguous

Ambiguity

Ambiguity of words or phrases is the ability to express more than one interpretation. It is distinct from vagueness, which is a statement about the lack of precision contained or available in the information.Context may play a role in resolving ambiguity...

word. In the premise, Timmy says that Billy is good at some particular activity, in this case tennis. In the conclusion, Timmy states that Billy is a morally good person. These are clearly two different senses of the word "good". The premise might be true but the conclusion can still be false: Billy might be the best tennis player in the world but a rotten person morally. However, it is not legitimate to infer he is a bad person on the ground there has been a fallacious argument on the part of Timmy. Nothing concerning Billy's moral qualities is to be inferred from the premise. Appropriately, since it plays on an ambiguity, this sort of fallacy is called the fallacy of equivocation

Equivocation

Equivocation is classified as both a formal and informal logical fallacy. It is the misleading use of a term with more than one meaning or sense...

, that is, equating two incompatible terms or claims.

Example 2

One posits the argument:

1. Nothing is better than eternal happiness.
2. Eating a hamburger is better than nothing.
3. Therefore, eating a hamburger is better than eternal happiness.

This argument has the appearance of an inference that applies transitivity

Transitive relation

In mathematics, a binary relation R over a set X is transitive if whenever an element a is related to an element b, and b is in turn related to an element c, then a is also related to c....

 of the two-placed relation is better than, which in this critique we grant is a valid property. The argument is an example of syntactic ambiguity. In fact, the first premise semantically does not predicate an attribute of the subject, as would for instance the assertion

Nothing is better than eternal happiness.

In fact it is semantically equivalent to the following universal quantification

Universal quantification

In predicate logic, universal quantification formalizes the notion that something is true for everything, or every relevant thing....

:

Everything fails to be better than eternal happiness.

So instantiating this fact with eating a hamburger, it logically follows that

Eating a hamburger fails to be better than eternal happiness.

Note that the premise A hamburger is better than nothing does not provide anything to this argument. This fact really means something such as

Eating a hamburger is better than eating nothing at all.

Thus this is a fallacy of equivocation.

Deductive Fallacy

In philosophy

Philosophy

Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

, the term logical fallacy properly refers to a formal fallacy: a flaw in the structure of a deductive

Deductive reasoning

Deductive reasoning, also called deductive logic, is reasoning which constructs or evaluates deductive arguments. Deductive arguments are attempts to show that a conclusion necessarily follows from a set of premises or hypothesis...

 argument which renders the argument invalid

Validity

In logic, argument is valid if and only if its conclusion is entailed by its premises, a formula is valid if and only if it is true under every interpretation, and an argument form is valid if and only if every argument of that logical form is valid....

.

However, it is often used more generally in informal discourse to mean an argument which is problematic for any reason, and thus encompasses informal fallacies as well as formal fallacies.

The presence of a formal fallacy in a deductive argument does not imply anything about the argument's premises or its conclusion (see fallacy fallacy). Both may actually be true, or even more probable as a result of the argument (e.g., appeal to authority), but the deductive argument is still invalid because the conclusion does not follow from the premises in the manner described. By extension, an argument can contain a formal fallacy even if the argument is not a deductive one; for instance an inductive argument that incorrectly applies principles of probability

Probability

Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...

 or causality

Causality

Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....

 can be said to commit a formal fallacy.

Formalisms and frameworks used to understand fallacies

A different approach to understanding and classifying fallacies is provided by argumentation theory

Argumentation theory

Argumentation theory, or argumentation, is the interdisciplinary study of how humans should, can, and do reach conclusions through logical reasoning, that is, claims based, soundly or not, on premises. It includes the arts and sciences of civil debate, dialogue, conversation, and persuasion...

; see for instance the van Eemeren, Grootendorst. In this approach, an argument is regarded as an interactive protocol

Protocol (diplomacy)

In international politics, protocol is the etiquette of diplomacy and affairs of state.A protocol is a rule which guides how an activity should be performed, especially in the field of diplomacy. In diplomatic services and governmental fields of endeavor protocols are often unwritten guidelines...

 between individuals which attempts to resolve a disagreement. The protocol is regulated by certain rules of interaction, and violations of these rules are fallacies. Many of the fallacies in the list above are best understood as being fallacies in this sense.

Other systems of classification

Of other classifications of fallacies in general the most famous are those of Francis Bacon and J. S. Mill

John Stuart Mill

John Stuart Mill was a British philosopher, economist and civil servant. An influential contributor to social theory, political theory, and political economy, his conception of liberty justified the freedom of the individual in opposition to unlimited state control. He was a proponent of...

. Bacon (Novum Organum

Novum Organum

The Novum Organum, full original title Novum Organum Scientiarum, is a philosophical work by Francis Bacon, written in Latin and published in 1620. The title translates as new instrument, i.e. new instrument of science. This is a reference to Aristotle's work Organon, which was his treatise on...

, 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. With these should be compared the Offendicula of Roger Bacon, contained in the Opus maius, pt. i. J. S. Mill discussed the subject in book v. of his Logic, and Jeremy Bentham

Jeremy Bentham

Jeremy Bentham was an English jurist, philosopher, and legal and social reformer. He became a leading theorist in Anglo-American philosophy of law, and a political radical whose ideas influenced the development of welfarism...

's Book of Fallacies (1824) contains valuable remarks. See Rd. Whateley's Logic, bk. v.; A. de Morgan, Formal Logic (1847) ; A. Sidgwick, Fallacies (1883) and other textbooks.

See also

• Attacking Faulty Reasoning
  Attacking Faulty Reasoning
  Attacking Faulty Reasoning is a textbook on logical fallacies by T. Edward Damer that has been used for many years in a number of college courses on logic, critical thinking, argumentation, and philosophy. It explains 60 of the most commonly committed logical fallacies. Each of the fallacies is...
  
  
• Cognitive distortion
  Cognitive distortion
  Cognitive distortions are exaggerated and irrational thoughts identified in cognitive therapy and its variants, which in theory perpetuate certain psychological disorders. The theory of cognitive distortions was first proposed by Aaron T. Beck. Eliminating these distortions and negative thoughts is...
  
  
• Evidence
  Evidence
  Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either presumed to be true, or were themselves proven via evidence, to demonstrate an assertion's truth...
  
  
• List of cognitive biases

• List of fallacies
• List of paradoxes
• Sophistry
• Straight and Crooked Thinking
  Straight and Crooked Thinking
  Straight and Crooked Thinking, first published in 1930 and revised in 1953, is a book by Robert H. Thouless which describes, assesses and critically analyses flaws in reasoning and argument. Thouless describes it as a practical manual, rather than a theoretical one.-Synopsis:*No. 3. proof by...
  
  
• Truth
  Truth
  Truth has a variety of meanings, such as the state of being in accord with fact or reality. It can also mean having fidelity to an original or to a standard or ideal. In a common usage, it also means constancy or sincerity in action or character...
  
  

Further reading

• C. L. Hamblin, Fallacies, Methuen London, 1970. reprinted by Vale Press in 1998 as ISBN 0916475247.
• Douglas N. Walton, Informal logic: A handbook for critical argumentation. Cambridge University Press
  Cambridge University Press
  Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...
  
  , 1989.

Historical texts

• Aristotle
  Aristotle
  Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
  
  , On Sophistical Refutations, De Sophistici Elenchi. library.adelaide.edu.au
• William of Ockham
  William of Ockham
  William of Ockham was an English Franciscan friar and scholastic philosopher, who is believed to have been born in Ockham, a small village in Surrey. He is considered to be one of the major figures of medieval thought and was at the centre of the major intellectual and political controversies of...
  
  , Summa of Logic (ca. 1323) Part III.4.
• John Buridan, Summulae de dialectica Book VII.
• Francis Bacon
  Francis Bacon
  Francis Bacon, 1st Viscount St Albans, KC was an English philosopher, statesman, scientist, lawyer, jurist, author and pioneer of the scientific method. He served both as Attorney General and Lord Chancellor of England...
  
  , the doctrine of the idols in Novum Organum Scientiarum, Aphorisms concerning The Interpretation of Nature and the Kingdom of Man, XXIIIff. fly.hiwaay.net
• Arthur Schopenhauer
  Arthur Schopenhauer
  Arthur Schopenhauer was a German philosopher known for his pessimism and philosophical clarity. At age 25, he published his doctoral dissertation, On the Fourfold Root of the Principle of Sufficient Reason, which examined the four separate manifestations of reason in the phenomenal...
  
  , The Art of Controversy | Die Kunst, Recht zu behalten - The Art Of Controversy (bilingual), (also known as "Schopenhauers 38 stratagems"). gutenberg.net
• John Stuart Mill
  John Stuart Mill
  John Stuart Mill was a British philosopher, economist and civil servant. An influential contributor to social theory, political theory, and political economy, his conception of liberty justified the freedom of the individual in opposition to unlimited state control. He was a proponent of...
  
  , A System of Logic - Raciocinative and Inductive. Book 5, Chapter 7, Fallacies of Confusion. la.utexas.edu

External links

• SEP entry on informal logic has a section on fallacy theory
• Appeal to Authority Appeal to Authority Logical Fallacy
• FallacyFiles.org contains categorization of fallacies with examples.
• 42 informal logical fallacies explained by Dr. Michael C. Labossiere (including examples), nizkor.org
• 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
• LogicalFallacies.Info
• An Informal Fallacy Primer, acontrario.org
• Stephen Downes Guide to the Logical Fallacies, onegoodmove.org
• "Love is a Fallacy", a short story written by Max Shulman
  Max Shulman
  Max Shulman was an American writer and humorist best known for his television and short story character Dobie Gillis, as well as for best-selling novels.-Early life and career:...
  
  . WebCitation archive.