this might be pretty basic question in terms of the theoretical, but I still find people's answers interesting, so I hope this fulfills your request. When people are defining genre,(f.ex. gothic lit, restoration lit, post modern etc) what do you think are the important defining factors? When does a trope begin to become a genre? How useful do you think this term really is? Do you lean more toward an arbitrary denotation or do you think genres should be more fluidly defined?
my first thought in response to this question was of a kerfuffle that I vaguely remember arising a little while ago over a man (?) who marketed a book as a romance despite the fact that it–contrary to all the expectations for that genre–didn’t have a “happily ever after,” which pissed a lot of people off. which suggests that genre, at least in terms of the marketing of contemporary literature (especially “pulp” literature / “genre fiction”), has the function of guiding & organising audience expectations–aka when you pick up a work in a certain genre, you should know what you’re getting. and romance is well-known for circulating the same few dozen well-worn tropes and settings (because, to be fair, a lot of them work). so this author committed a faux pas because he used the popularity of the romance genre & the loyalty of its readers to advertise his book without respecting the accepted boundaries of that genre (& the fact that he was seen to be taking advantage of the readers of a genre generally dominated by women probably didn’t help much either), thus defying reader expectations in a way that was deemed unacceptable. so I’d say that in terms of contemporary literature, a genre consists of one or two things that are requisite (a romance has to have a romance with a ‘happy’ ending, historical fiction has to be set in the past, war stories–you get the picture) and–what is harder to tell the boundaries of–a general cluster of tropes, settings, moods, and themes that are commonly called on in that genre. & I don’t think it’s unfair to say that all of this–the interest in directing reader expectations & allowing people to know what they’re getting, & thus to get what they want on demand–often has more to do with marketing (& with–not to be that person–the demand for instant entertainment guided by capitalist ennui and alienation) than with anything else.
in terms of historical or more “literary” genres like the ones you’ve named, I think that gets more complicated–some of them (like Gothic literature) can be thought of in terms of their common tropes, themes, settings, and moods (all of which are of course in conversation with the historical period during which they were written), while some of them (like Restoration literature) can refer to very different works in terms of tropes and themes that were written during the same time period or in reaction to the same event. what I think is most interesting & valuable in terms of tracing literary movements throughout history (where, for example, does “Romantic” literature begin and end, and what basic premises, tropes, and themes does it revolve around?) lies not in trying to draw strict delineations between one genre (or one movement or period) and another, but in trying to understand how that literature was influenced by the sociopolitical environment in which it was written, and how it was influenced by & influenced other literary and artistic movements (over time or distance). aka, what was Romanticism a reaction to (artistically and politically), what sentiments and ideas did it express & what tools did it use to do so, what was the reaction to it / what impact did it have on the Victorian art and literature that succeeded it?
so, to answer your question, I think that a trope becomes a genre when it tends to cluster together with other tropes and themes in recognisable patterns–whether those tropes are employed on purpose (as in modern genre fiction, & certainly in a lot of e.g. Gothic fiction too) or whether the analysis that defines a genre is retrospective (& there’s definitely more than one possible way to sort these things). & so !!! rather than a way of definitively sorting and organising works, you can think of genre as a tool–a toolkit for writing a story; a handy set of guidelines that, through the use of familiar conventions, allow you to convey to readers what you want them to understand; a tool for analysing works in terms of what they have in common that best allows you to tease out 1. how those commonalities are potentially shaped by sociohistorical realities and 2. the differences between those works, and why those differences matter.
which brings me very nicely to my second thought–the idea of using the constraints and expectations of genre constructively to give an amount of structure to a story: but only just enough structure to set off what’s different or new about it. a lot of authors whose works are considered both genre and literary fiction (Margaret Atwood comes to mind) do this. it’s perhaps a bit similar to genre in music: if you don’t listen to a lot of a certain genre of music, it’s bound to all sound the same to you–it’s only once you become more familiar with the conventions & what most works in that genre have in common that you can appreciate how some artists play with, adapt, or even defy those conventions while remaining clearly within / heavily influenced by the genre. thus Jane Austen in Persuasion can lampoon some of the trappings of Romanticism–having her heroine caution a man against reading too much Byron, for example–but still write a Romantic plot in showing said heroine renounce a too-heavy reliance on pragmatism and embrace romance as she grows older. & the line between something like that vs. something being entirely outside of the genre that inspired it (Northanger Abbey being a parody of Gothic fiction, for example, or Middlemarch being a response to the preponderance of the marriage plot in Romantic novels) is, I’d imagine, pretty fluid.
tl;dr: genre of course isn’t innate or rigidly defined, but I think it’s a valuable concept & tool for organising works of literature into various sets of conventions that, by their very conventionality, make deviation from them immediately noticeable–thus an analysis of genre can help you to pay attention to (& can help a writer bring attention to) what’s important in a work of literature.
