Humans not only inhabit a physical world; they inhabit a world of ideas. Complex ideas, simple ideas, brilliant ideas, stupid ideas, ad infinitum. All such ideas have a way of circulating and coalescing into cultural narratives that provide societies with a common thematic thread, a handy code of conduct, a basis for interaction.
Cultural narratives provide a framework for engagement at all levels of society. They influence many things including social policy and the content of the media universe.
However they remain unreliable, a mixture of fact and fiction. Competing narratives can arise to explain mass social events or justify mass action. When social conflicts occur, conflicting narratives are at play. When intractable problems arise, it can be assumed that there is something amiss with a prevailing narrative.