Conventional wisdom is a term coined by the economist John Kenneth Galbraith, used to describe certain ideas or explanations that are generally accepted as true by the public.
Often conventional wisdom is portrayed as being incorrect. Many urban legends, for example are accepted on the basis of being "conventional wisdom". Conventional wisdom is also often seen as an obstacle to introducing new theories, explanations, or revisionism.
The idea of Conventional Wisdom is also used in a political sense, often related closely with the phenomenon of Talking Points. It is used pejoratively to refer to the idea that statements which are repeated over and over become conventional wisdom regardless of whether or not they are true.
See also
Boiling frog