Wikipedia:Fringe theories

In Wikipedia parlance, the term fringe theory is used in a broad sense to describe an idea that departs significantly from the prevailing views or mainstream views in its particular field. Because Wikipedia aims to summarize significant opinions with representation in proportion to their prominence, a Wikipedia article should not make a fringe theory appear more notable or more widely accepted than it is. Statements about the truth of a theory must be based upon independent reliable sources. If discussed in an article about a mainstream idea, a theory that is not broadly supported by scholarship in its field must not be given undue weight,[1] and reliable sources must be cited that affirm the relationship of the marginal idea to the mainstream idea in a serious and substantial manner.

There are numerous reasons for these requirements. Wikipedia is not and must not become the validating source for non-significant subjects, and it is not a forum for original research.[2] For writers and editors of Wikipedia articles to write about controversial ideas in a neutral manner, it is of vital importance that they simply restate what is said by independent secondary sources of reasonable reliability and quality.

The governing policies regarding fringe theories are the three core content policies Neutral point of view, No original research, and Verifiability. Jointly these say that articles should not contain any novel analysis or synthesis, that material likely to be challenged needs a reliable source, and that all majority and significant-minority views published in reliable sources should be represented fairly and proportionately. Should any inconsistency arise between this guideline and the content policies, the policies take precedence.

Fringe theories and related articles have been the subject of several arbitration cases. See Wikipedia:Fringe theories/Arbitration cases.