This is an essay on notability.

It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints.

This page in a nutshell: All articles on Wikipedia should be justified based on Wikipedia policy, especially verifiability and no original research. Notability is just a guideline. Notability is a useful tool for determining whether an article can meet Wikipedia policy in terms of being reliable. But notability must not be treated as policy and should not be the means of justifying which articles should be included or excluded.

Postulates

All content must be verifiable

This easily follows from Wikipedia:Verifiability. All claims that are challenged or likely to be challenged must come with a citation to a reliable source. This relates to a core goal of notability—proving that an entity exists.