August 2010

A List of Common Logical Fallacies in Propaganda and Debate
The majority of these descriptions are lifted from many pages across Wikipedia, and are condensed here. This page is intended as a quick and convenient reference for those who do not have the time to browse entire libraries.

Contents:

Ad Lapidem
Ad Lapidem is a logical fallacy where someone dismisses a statement as absurd without giving a reason why it is supposedly absurd.

Ad hominem
An ad hominem argument, also known as argumentum ad hominem (Latin: "argument to the person", "argument against the man") is a logical fallacy consisting of replying to an argument by attacking or appealing to the person making the argument, rather than by addressing the substance of the argument. It is most commonly used to refer specifically to the ad hominem abusive, or argumentum ad personam, which consists of criticizing or personally attacking an argument's proponent in an attempt to discredit that argument.

Affirming the consequent
Affirming the consequent is a logical fallacy that assumes that because a hypothetical situation would bear a certain effect, that the occurrence of said effect implies that the aforementioned situation occured.

Appeal to authority
An appeal to authority or argument by authority is a type of argument in logic, consisting on basing the truth value of an otherwise unsupported assertion on the authority, knowledge or position of the person asserting it. It is also known as argument from authority, argumentum ad verecundiam (Latin: argument to respect) or ipse dixit (Latin: he himself said it). It is one method of obtaining propositional knowledge, but a fallacy in regards to logic, because the validity of a claim does not follow from the credibility of the source. The corresponding reverse case would be an ad hominem attack: to imply that the claim is false because the asserter is objectionable.

Appeal to consequences
Appeal to consequences, also known as argumentum ad consequentiam, is an argument that concludes a premise (typically a belief) to be either true or false based on whether the premise leads to desirable or undesirable consequences.

Appeal to fear
An appeal to fear (also called argumentum ad metam or argumentum in terrorem) is a logical fallacy in which a person attempts to create support for her or his idea by increasing fear and prejudice toward a competitor.

Appeal to flattery
Appeal to flattery is a logical fallacy in which a person uses flattery, excessive compliments, in an attempt to win support for their side.

Flattery is often used to hide the true intent of an idea or proposal. Praise offers a momentary personal distraction that can often weaken judgment. Moreover, it is usually a cunning form of appeal to consequences, since the audience is subject to be flattered as long as they comply with the flatterer.

Appeal to nature
Appeal to nature is a simplified type of naturalistic fallacy in argument form. An appeal to nature fallacy consists of a claim that something is good or right because it is natural, or that something is bad or wrong because it is unnatural

Appeal to novelty
The appeal to novelty (also called argumentum ad novitatem) is a logical fallacy in which someone prematurely claims that an idea or proposal is correct or superior, exclusively because it is new and modern.

Appeal to pity
An appeal to pity (also called argumentum ad misericordiam) is a logical fallacy in which someone tries to win support for their argument or idea by exploiting their opponent's feelings of pity or guilt.

Appeal to probability
Appeal to probability is a logical fallacy, often used in conjunction with other fallacies. It assumes that because something could happen, it is inevitable that it will happen.

Appeal to spite
Appeal to spite (also called argumentum ad odium) is a logical fallacy in which someone attempts to win favor for an argument by exploiting existing feelings of bitterness, spite, or schadenfreude in the opposing party.

Appeal to tradition
Appeal to tradition, also known as appeal to common practice or argumentum ad antiquitatem or false induction is a common logical fallacy in which a thesis is deemed correct on the basis that it has a long standing tradition behind. Essentially: "This is right because we've always done it this way."

Argumentum ad baculum
Argumentum ad baculum (Latin: argument to the cudgel or appeal to the stick), 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.

Argumentum ad crumenam
An argumentum ad crumenam argument, also known as an argument to the purse is a logical fallacy of concluding that a statement is correct because the speaker is rich.

Argumentum ad lazarum
Argumentum ad lazarum or appeal to poverty is the logical fallacy of thinking a conclusion is correct because the speaker is poor.

Argumentum ad nauseam
Argumentum ad nauseam or argument from repetition or argumentum ad infinitum is a flawed argument, whereby some statement is made repeatedly (possibly by different people) until nobody cares to refute it anymore, at which point the statement is asserted to be true because it is no longer challenged.

Argumentum ad populum
An argumentum ad populum, appeal to the people, in logic, is a fallacious argument that concludes a proposition to be true because many or all people believe it; it alleges that "If many believe so, it is so." In ethics this argument is stated, "if many find it acceptable, it is acceptable."

Argument from fallacy
Also argumentum ad logicam - assumes that if an argument is fallacious, its conclusion must be false.

Argument from ignorance
The argument from ignorance, also known as argumentum ad ignorantiam or argument by lack of imagination, is a logical fallacy in which it is claimed that a premise is true only because it has not been proven false, or that a premise is false only because it has not been proven true.

Argument from silence
The argument from silence (also called argumentum a silentio in Latin) is that the silence of a speaker or writer about X proves or suggests that the speaker or writer is either ignorant of X or has a motive to remain silent about X. When used as a logical proof in pure reasoning, the argument is classed among the fallacies, but it may be valid circumstantial evidence in practical reasoning.

Association fallacy
An association fallacy is a type of logical fallacy which asserts that qualities of one are inherently qualities of another, merely by association.

Begging the question
Begging the question in logic, also known as circular reasoning and by the Latin name petitio principii, is an informal fallacy found in many attempts at logical arguments. An argument which begs the question is one in which a premise presupposes the conclusion in some way.

Biased sample
A biased sample is one that is falsely taken to be typical of a population from which it is drawn.

Bulverism
Bulverism is a logical fallacy coined by C. S. Lewis where rather than proving that an argument is wrong, a person instead assumes it wrong, and then goes on to explain why the other person held that argument.

Chronological snobbery
Chronological snobbery is the logical fallacy that the thinking, art, or science of an earlier time is inherently inferior when compared to that of the present.

Circular cause and consequence
Circular cause and consequence is a logical fallacy where the consequence of the phenomenon is claimed to be its root cause. This is also known as the the chicken or the egg fallacy.

Cum hoc ergo propter hoc
cum hoc ergo propter hoc (Latin for "with this, therefore because of this") (also known as false cause) is the logical fallacy by which two events that occur together are claimed to have a cause-and-effect relationship. By contrast, the fallacy post hoc ergo propter hoc requires that one event occur before the other and so may be considered a type of cum hoc. "Correlation does not imply causation" is a phrase used in science and statistics to emphasize that correlation between two variables does not automatically imply that one causes the other (though correlation is necessary for causation and can indicate possible causes or areas for further investigation). "More children in town A have leukemia than in town B. Therefore, there must be something wrong with town A."

Denying the antecedent
Denying the antecedent, a logical fallacy that assumes that because a hypothetical situation would bear a certain effect, that the absence of the hypothesised trigger situation means that the effect earlier described did not occur.

Etymological fallacy
An etymological fallacy is a linguistical misconception based on the idea that the etymology of a word or phrase is its actual meaning.

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 (or even of every proper part).

Fallacy of Relative Privation
The fallacy of relative privation, or appeal to bigger problems, is an informal fallacy in which an opponent's arguments about issues are minimized, deemed unimportant, or dismissed on the grounds that more important topics and issues exist, regardless of whether these problems are relevant to the question at hand or not. The use of the fallacy has also been referred to as "whataboutery". A well-known example of this fallacy is the response "but there are children starving in Africa," with the implication that any issue less serious is not worthy of discussion. Also "First World Problem", "think of the children" and the related "Nirvana Fallacy" and "perfect solution fallacy" (false dichotomy).

Fallacy of the single cause
The fallacy of the single cause, also known as joint effect or causal oversimplification, is a logical fallacy of causation that occurs when it is assumed that there is one, simple cause of an outcome when in reality it may have been caused by a number of only jointly sufficient causes.

False choice
The logical fallacy of false choice is a correlative-based fallacy in which options are presented as being exclusive when they may not be. It is often used to obscure the likelihood of one option or to reframe an argument on the user's terms.

False dilemma
The logical fallacy of false dilemma also known as falsified dilemma, fallacy of the excluded middle, black and white thinking, false dichotomy, false correlative, either/or fallacy and bifurcation involves a situation in which two alternative points of view are held to be the only options, when in reality there exist one or more other options which have not been considered.

Gambler's fallacy
"The roulette ball has landed on odd numbers eight times in a row. Therefore, it's more likely to land on an even number next time."

Genetic fallacy
The genetic fallacy is a logical fallacy based on the irrelevant appraisal of something based on its origin. It occurs when one attempts to reduce the significance of an idea, person, practice, or institution merely to an account of its origin (genesis) or earlier form. This overlooks any difference to be found in the present situation, typically transferring the positive or negative esteem from the earlier context.

Hasty generalization
Hasty generalization is the fallacy of examining just one or very few examples or studying a single case, and generalizing that to be representative of the whole class of objects or phenomena. (Hasty generalization, also known as fallacy of insufficient statistics, fallacy of insufficient sample, fallacy of the lonely fact, leaping to a conclusion, hasty induction, law of small numbers, unrepresentative sample or secundum quid, is the logical fallacy of reaching an inductive generalization based on too little evidence.)

Ignoratio elenchi
Ignoratio elenchi (also known as irrelevant conclusion) is the logical fallacy of presenting an argument that may in itself be valid, but which proves or supports a different proposition than the one it is purporting to prove or support.

Many questions
Many questions, also known as complex question, presupposition, loaded question, or plurium interrogationum (Latin, "of many questions"), is a logical fallacy. It is committed when someone asks a question that presupposes something that has not been proven or accepted by all the people involved. This fallacy is often used rhetorically, so that the question limits direct replies to those that serve the questioner's agenda.

Middle ground logical fallacy
The middle ground logical fallacy (also called argumentum ad temperantiam) asserts that a compromise between two positions is correct.

Misleading vividness
The logical fallacy of misleading vividness involves describing some occurrence in vivid detail, even if it is an exceptional occurrence, to convince someone that it is a problem.

Overwhelming exception
The overwhelming exception is related to the hasty generalization, but working from the other end. It is a generalization which is accurate, but tags on a qualification which eliminates enough cases (as exceptions); that what remains is much less impressive than what the original statement might have led one to assume.

Package deal
The logical fallacy of the package deal consists of assuming that things often grouped together by tradition or culture must always be grouped that way.

Perfect solution fallacy
The perfect solution fallacy is a logical fallacy that occurs when an argument assumes that a perfect solution exists and/or that a solution should be rejected because some part of the problem would still exist after it was implemented.

Poisoning the well
Poisoning the well is a logical fallacy where adverse information about someone is preemptively presented to an audience, with the intention of discrediting or ridiculing everything that person is about to say.

Post hoc ergo propter hoc
Post hoc ergo propter hoc, Latin for "after this, therefore because of this", is a logical fallacy (of the questionable cause variety) which 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, coincidental correlation or correlation not causation. It is subtly different from the fallacy cum hoc ergo propter hoc, in which the chronological ordering of a correlation is insignificant. Post hoc is a particularly tempting error because temporal sequence appears to be integral to causality. The fallacy lies in coming to a conclusion based solely on the order of events, rather than taking into account other factors that might rule out the connection.

Proof by example
Proof by example (also known as inappropriate generalisation) is a logical fallacy whereby one or more examples are claimed as "proof" for a more general statement.

Quoting out of context
The practice of quoting out of context, sometimes referred to as contextomy, is a logical fallacy and type of false attribution in which a passage is removed from its surrounding matter in such a way as to distort its intended meaning.

Slippery slope
In debate or rhetoric, the slippery slope is an argument for the likelihood of one event or trend given another. It suggests that an action will initiate a chain of events culminating in an undesirable event later.

Spotlight fallacy
The Spotlight fallacy is committed when a person uncritically assumes that all members or cases of a certain class or type are like those that receive the most attention or coverage in the media. This line of reasoning has the following form:

* Xs with quality Q receive a great deal of attention or coverage in the media. Therefore all Xs have quality Q.

Straw man
A straw man argument is a logical fallacy based on misrepresentation of an opponent's position. To "set up a straw man" or "set up a straw-man argument" is to create a position that is easy to refute, then attribute that position to the opponent.

Style over substance
The style over substance fallacy occurs when one emphasises the way in which the argument is presented, while marginalising (or outright ignoring) the content of the argument.

Tu quoque
Tu quoque (Latin for "You, too" or "You, also") is an argument that asserts or implies that a certain position is false and/or should be disregarded because its proponent fails to consistently act in accordance with that position; it attempts show that a criticism or objection applies equally to the person making it. It can be considered an ad hominem argument, since it focuses on the opposite party itself, rather than its positions.

Wishful thinking
Wishful thinking is the formation of beliefs and making decisions according to what might be pleasing to imagine instead of by appealing to evidence or rationality.

Wrong direction
Wrong direction is a logical fallacy of causation where cause and effect are reversed. The cause is said to be the effect and vice versa.

"Organizations frequently take action contrary to the desires of their members, and thereby defeat the very purpose they set out to achieve." --Dr. Jerry B. Harvey

The Abilene paradox is a paradox in which a group of people collectively decide on a course of action that is counter to the preferences of any of the individuals in the group. It involves a common breakdown of group communication in which each member mistakenly believes that their own preferences are counter to the group's and, therefore, does not raise objections. A common phrase relating to the Abilene paradox is a desire to not "rock the boat".

Origins

The Abilene paradox was introduced by management expert Jerry B. Harvey in his article The Abilene Paradox and other Meditations on Management. The name of the phenomenon comes from an anecdote in the article which Harvey uses to elucidate the paradox:

On a hot afternoon visiting in Coleman, Texas, the family is comfortably playing dominoes on a porch, until the father-in-law suggests that they take a trip to Abilene [53 miles north] for dinner. The wife says, "Sounds like a great idea." The husband, despite having reservations because the drive is long and hot, thinks that his preferences must be out-of-step with the group and says, "Sounds good to me. I just hope your mother wants to go." The mother-in-law then says, "Of course I want to go. I haven't been to Abilene in a long time."

The drive is hot, dusty, and long. When they arrive at the cafeteria, the food is as bad as the drive. They arrive back home four hours later, exhausted.

One of them dishonestly says, "It was a great trip, wasn't it?" The mother-in-law says that, actually, she would rather have stayed home, but went along since the other three were so enthusiastic. The husband says, "I wasn't delighted to be doing what we were doing. I only went to satisfy the rest of you." The wife says, "I just went along to keep you happy. I would have had to be crazy to want to go out in the heat like that." The father-in-law then says that he only suggested it because he thought the others might be bored.

The group sits back, perplexed that they together decided to take a trip which none of them wanted. They each would have preferred to sit comfortably, but did not admit to it when they still had time to enjoy the afternoon.

Groupthink

The phenomenon may be a form of groupthink. It is easily explained by social psychology theories of social conformity and social influence which suggest that human beings are often very averse to acting contrary to the trend of the group. Likewise, it can be observed in psychology that indirect cues and hidden motives often lie behind peoples' statements and acts, frequently because social disincentives discourage individuals from openly voicing their feelings or pursuing their desires.

The Abilene Paradox is related to the concept of groupthink in that both theories appear to explain the observed behavior of groups in social contexts. The crux of the theory is that groups have just as many problems managing their agreements as they do their disagreements. This observation rings true among many researchers in the social sciences and tends to reinforce other theories of individual and group behavior.

Applications of the theory

The theory is often used to help explain extremely poor business decisions, especially notions of the superiority of "rule by committee." A technique mentioned in the study and/or training of management, as well as practical guidance by consultants, is that group members, when the time comes for a group to make decisions, should ask each other, "Are we going to Abilene?" to determine whether their decision is legitimately desired by the group's members or merely a result of this kind of groupthink. This anecdote was also made into a short film[5] for management education.

See also (12 pages):

http://www.rmastudies.org.nz/documents/AbileneParadoxJerryHarvey.pdf

Daniel Dendy

Thursday, August 5, 2010

Argument and logic errors & problems

Sunday, August 1, 2010

The Prisoners' Dilemma

The Abilene paradox

The Pollyanna Principle (positive bias)