Tag Archives: logical fallacy

Special Pleading

Special pleading is a form of inconsistency in which the reasoner doesn’t apply his or her principles consistently. It is the fallacy of applying a general principle to various situations but not applying it to a special situation that interests the arguer even though the general principle properly applies to that special situation, too.

Example:

Everyone has a duty to help the police do their job, no matter who the suspect is. That is why we must support investigations into corruption in the police department. No person is above the law. Of course, if the police come knocking on my door to ask about my neighbors and the robberies in our building, I know nothing. I’m not about to rat on anybody.

In our example, the principle of helping the police is applied to investigations of police officers but not to one’s neighbors.

Source: The Internet Encyclopedia of Philosophy

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Appeal to the minority

by Tim Harding

Alternative things have been ‘cool’ since the 1960s. They include alternative music, alternative lifestyles and of course, so-called ‘alternative medicine’. At least part of the appeal of such alternatives is the rejection of majority views perceived as mainstream or conservative.                   

An appeal to the minority is a logical fallacy that occurs when something is asserted to be true because most people don’t believe it. It is the opposite of an appeal to popularity where an advocate asserts that because the great majority of people agree with his or her position on an issue, he or she must be right (The Skeptic, September 2012). The logical form of the appeal to the minority fallacy is:

Premise 1: X is a minority view (as compared to majority view Y).

Premise 2: Minority views are more often true than majority views.

Conclusion: X is more likely to be true than Y.

To give some examples of this fallacy: ‘just like Copernicus, we in the Flat Earth Society are willing to defy the wrong-headed orthodoxy of the mainstream scientific community’ and ‘the medical profession and pro-vaccine sheeple have been conned by Big Pharma to maximise their profits’.

This fallacy has also been called ‘second-option bias’, which is a well-documented phenomenon among fringe and counterculture groups where they assume that any widely-held opinion among the general population must be untrue, and therefore, the prevailing contrary opinion must be right. This is an important driver in conspiracy theories, pseudoscience, quackery and other fields where a person feels their views and ideas are being marginalised by mainstream society.

Ironically, an appeal to the minority is inherently limited. If someone successfully persuades other people that they are right, then their opinion would increasingly lose its minority status — and eventually would become majority opinion.

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Appeal to Ignorance

 

by Tim Harding

The scope of the Appeal to Ignorance fallacy (Argumentum ad Ignorantiam in Latin) is more limited than its title would suggest. In the specific context of this fallacy, the word ignorance represents ‘a lack of contrary evidence’ rather than a lack of education or knowledge. The fallacy title was likely coined by the philosopher John Locke in the late 17th century.

In informal logic, this fallacy asserts that a proposition is true because it has not yet been shown to be false, or a proposition is false because it has not yet been shown to be true. This represents a type of false dichotomy, in that it excludes the possibility that there may have been an insufficient investigation to determine whether the proposition is either true or false. In other words, ‘absence of evidence is not evidence of absence.’

In rhetorical debates, appeals to ignorance are sometimes used in an attempt to shift the burden of proof.  A typical example is as follows: ‘In spite of all the talk, not a single flying saucer report has been authenticated. We may assume, therefore, there are no such things as flying saucers.’ An absurd but logically equivalent example is: ‘Although NASA has shown that the surface of the moon is not made of green cheese, it has not conclusively demonstrated that the Moon’s core is not made of it; therefore, the moon’s core is made of green cheese.

This fallacy is a potential trap that empiricists need to be wary of falling into. We cannot prove the non-existence of anything, so the burden of proof lies with those who claim the existence of something, rather than those who doubt it. So, we should always remain open to the possibility of new evidence in support of a claim, even if no such evidence has ever been found.

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Non sequitur

Non sequitur (Latin for “it does not follow”), 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 premises and the conclusion.

All invalid arguments are special cases of non sequitur.  Many types of known non sequitur argument forms have been classified into various logical fallacies, such as Affirming the ConsequentBegging the question and  Fallacies of Composition and Division.

The term has special applicability in law, having a formal legal definition.

 

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