Common knowledge

Common knowledge is knowledge that is known by everyone or nearly everyone, usually with reference to the community in which the term is used. Common knowledge need not concern one specific subject, e.g., science or history. Rather, common knowledge can be about a broad range of subjects, such as science, literature, history, and entertainment. Often, common knowledge does not need to be cited. Common knowledge is distinct from general knowledge. The latter has been defined by differential psychologists as referring to "culturally valued knowledge communicated by a range of non-specialist media", and is considered an aspect of ability related to intelligence. Therefore, there are substantial individual differences in general knowledge as opposed to common knowledge.

The assertion that something is "common knowledge" is sometimes associated with the fallacy argumentum ad populum (Latin: "appeal to the people"). The fallacy essentially warns against assuming that just because everyone believes something is true, it is true. Misinformation is easily introduced into rumours by intermediate messengers.

In broader terms, common knowledge is used to refer to information that a reader would accept as valid, such as information that many users may know. As an example, this type of information may include the temperature in which water freezes or boils. To determine if information should be considered common knowledge, you can ask yourself who your audience is, are you able to assume they already have some familiarity with the topic, or will the information’s credibility come into question.

Many techniques have been developed in response to the question of distinguishing truth from fact in matters that have become "common knowledge". The scientific method is usually applied in cases involving phenomena associated with astronomy, mathematics, physics, and the general laws of nature. In legal settings, rules of evidence generally exclude hearsay (which may draw on "facts" someone believes to be "common knowledge").

"Conventional wisdom" is a similar term also referring to ostensibly pervasive knowledge or analysis.

...
Wikipedia