Over on the Science Fiction & Fantasy Stack Exchange, some participants apply the following theoretical approach to the interpretation of fiction:
Sources can be divided into ‘canon’ (works accurately describing the universe) and apocrypha (works that purport to describe the universe but which can be rejected as false, for example, fan fiction).
Does this approach to literature have a name? Has it been studied? What is its history? Is it purely a ‘folk theory’ or does it have an academic counterpart? Terry Eagleton’s Literary Theory purports to give a “reasonably comprehensive account of modern literary theory” but does not mention it.
The earliest work I know that takes a similar approach is ‘Studies in the Literature of Sherlock Holmes’ (1911) by Ronald Knox, but Knox and the other early participants in the ‘Sherlockian game’ were clear that it was to be played with tongue in cheek:
The rule of the game is that it must be played as solemnly as a county cricket match at Lord’s: the slightest touch of extravagance or burlesque ruins the atmosphere.
Dorothy L. Sayers (1946). Unpopular Opinions, p. 7. London: Gollancz.