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Logic and rhetoric

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[Y]ou'll be familiar with the idea that a sample can be systematically unrepresentative: if you want to know about the health of the population as a whole, but you survey people in a GP waiting room, then you’re an idiot.
Ben Goldacre

Overgeneralization is a logical fallacy that occurs when a conclusion about a group is drawn from an unrepresentative sample, especially a sample that is too small or too narrow. It is the opposite of slothful induction.

The fallacy is an imprecision fallacy and an informal fallacy.


[edit] Alternate names

  • hasty generalization
  • a dicto secundum quid ad dictum simpliciter
  • unrepresentative sample
  • argument/statistics from small numbers
  • insufficient statistics
  • argument by generalization
  • faulty generalization
  • hasty conclusion
  • inductive generalization
  • insufficient sample
  • lonely fact fallacy
  • over-generalization

[edit] Form

P1: Sample S of population P has quality Q.
P2: Sample S is not representative of population P.
C1: Population P has quality Q.

[edit] Examples

[edit] Limited sample size

Three senior citizens died after receiving swine flu vaccine in 1976
Vaccines are bad for you.

What isn't stated is that 48,161,019 people were immunized, only 532 had any negative reactions after the vaccinations (.001%). Eventually 25 people had fatal reactions from Guillain–Barré syndrome, which was an unknown reaction to a relatively new vaccination at the time. By contrast it is estimated at least 50 million (high estimates put it at near 100) people died from the 1918 swine flu epidemic.[1]

[edit] Non-representative samples

There have been a number of scandals involving financial firms committing fraud.
All financial firms and workers are thieves stealing money from society.

It is part of the spotlight fallacy to come up with a "sample", which is often utilized by economic conspiracy theorists.

Stereotyping is an example of overgeneralization based on personal characteristics of a single person or small groups.

MS-13 is a ultra violent South American criminal gang. Daesh is a Sunni Muslim terrorist organization.
The bullshit "not all terrorists are Muslim but all Muslims are terrorists."
All Latinos are in violent gangs...or to Stormfront all minorities.

Demonization and bullshit used by bigots.

[edit] As a defense for cranks

In a mixture with the association fallacy, overgeneralization has been used to ward off criticisms of wingnuts in an attempt to associate themselves with more mainstream groups. It is often used to portray the entire fringe group as "victims" of the attack, in order to motivate a larger group to respond in their defense.

  • Stormfront and other neo-nazi groups often try to portray attacks against their hate as an attack against all Caucasians or all Christians.
  • Any criticism on fundamentalists is generalized to be about everyone who portrays that religion.[2]
  • Survivalists often claim that criticizing their constant rants that the end of the world is nearly here is a criticism of making preparations for emergencies encouraged by governmental agencies. More sane people have started calling themselves "Preppers" in an attempt to stop this overgeneralization.
  • In a stunning normal display of claiming to be a victim of media criticism, Sarah Palin has claimed that any criticism of what she says in a misogynistic attack against all women.[3][4][5]

[edit] See also

[edit] External links

[edit] Footnotes

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