Bestertester said:
For me, anything above a certain length must have a theme, or I'll lose interest. Anything below a certain length probably can't have a theme, because there's no room to develop a theme.
Sure they do. Poems have themes. Limericks are short and have themes. Haikus are even shorter and have themes.
A story idea -- premise -- is related to plot. It's the set-up, the scaffolding around which the story is built. The theme of a story is usually not singular, but there may be one main, central theme to a story, which is related to the story idea (plot premise.) A theme is the meaning which the author explores in the story, sometimes intentionally and sometimes accidentally. (Fiction authors are famous for often not knowing their own themes and one of the reasons it can be difficult to get fiction authors to clearly describe their work is because they don't know its themes and/or how to describe them in the context of the plot premise and characters.)
So take kmtolan's example. The plot premise is that a teenage girl falls for a teenage boy who turns out to be an android. That is the story idea that the story is built around. But what it means, what's going to be explored out of that premise -- the themes -- can vary widely. The theme could be humans' relationships to their machines. The theme could be how can we define identity, sentience and real emotion. The theme could be comic -- that teenage girls often fall for boys their families have difficulty accepting. The theme could be dramatic -- in the course of the love affair, the teenage girl learns about loss and what she values. And the story can have all of those themes together, explored in the one story premise.
If you give the same story idea to different authors, they will probably explore different themes with it. They will certainly have different styles with different uses of language and imagery, which affects how theme -- meaning -- is worked into the story. And readers themselves don't all experience the story idea or its themes the same way. They may see themes that the author didn't intend and/or didn't really do. They may completely miss themes the author intended. They will have preferences about what some material an author may use should mean. The emotional experience and meaning of the story will be different for each reader. So we discuss those interpretations -- the themes, the meanings -- of fictional story as part of the experience of reading the stories. This is a large part of studying literature, along with structure (plot, premise,) and characterization. They're all inter-connected -- and subjective -- but we value those subjective experiences and the discussion about them.
For most authors, theme develops out of playing around with a plot premise, characters or a setting/imagery. However, sometimes authors will start with a theme and come up with a premise, etc. And sometimes genre can impact themes. If you are going to write a romance, then romance will be a central theme the story is built around. But what the romantic themes of the particular premise and story are going to be will vary widely, especially as romances are character studies. If you are writing a mystery, then a central theme will be about trying to solve a mystery, but what the thematic meaning of that search will be will vary widely, etc.