Wikipedia:Verifiability, not truth

Wikipedia's core sourcing policy, Wikipedia:Verifiability, previously defined the threshold for inclusion in Wikipedia as "verifiability, not truth". "Verifiability" was used in this context to mean that material added to Wikipedia must have been published previously by a reliable source. Editors may not add their own views to articles simply because they believe them to be correct, and may not remove sources' views from articles simply because they disagree with them.

The phrase "the threshold for inclusion is verifiability, not truth" meant that verifiability is a necessary condition (a minimum requirement) for the inclusion of material, though it is not a sufficient condition (it may not be enough). Sources must also be appropriate, and must be used carefully, and must be balanced relative to other sources per Wikipedia's policy on due weight.

Wikipedia's articles are intended as intelligent summaries and reflections of current published knowledge within the relevant fields, an overview of the relevant literature. The Verifiability policy is related to another core content policy, Neutral point of view, which holds that we include all significant views on a subject. Citing reliable sources, for any material challenged or likely to be challenged, gives readers the chance to check for themselves that the most appropriate sources have been used, and used well (see below).

The Verifiability policy was later re-written in 2012 to clarify these points, stating that Wikipedia's "content is determined by previously published information rather than the beliefs or experiences of its editors. Even if you're sure something is true, it must be verifiable before you can add it". That we have rules for the inclusion of material does not mean Wikipedians have no respect for truth and accuracy, just as a court's reliance on rules of evidence does not mean the court does not respect truth. Wikipedia values accuracy, but it requires verifiability. Wikipedia does not try to impose "the truth" on its readers, and does not ask that they trust something just because they read it in Wikipedia. We empower our readers. We don't ask for their blind trust.

Sometimes we know for sure that the reliable sources are in error, but we cannot find replacement sources that are correct. As Douglas Adams wrote of The Hitchhiker's Guide to the Galaxy, "Where it is inaccurate it is at least definitively inaccurate. In cases of major discrepancy it's always reality that's got it wrong."