I thought of another story which seems to me to be a classic neat idea tale: "Nightfall" by Isaac Asimov. It's about an alien planet where night falls only rarely, due to a lot of suns. When night does fall, and people see the stars, they burn everything they can find out of terror -- and their civilization collapses. This happens over and over, each time night falls.
Asimov wrote the story is response to a line from Emerson on how people would marvel at the beauty of the stars, if they saw them only once in a thousand years.
The last time I reread it, I noticed it is not well written. But it will stay with me till my memory fails.
Asimov was not an especially good writer, but I remember the Foundation stories and the robot stories. Is there anyone reading this blog who cannot recite the three laws of robotics? How about psychohistory? Do we all remember how it works?
This kind of story is core to SF, as are ideas. I suspect ideas are not as important to fantasy, though there's a lot of fantasy written by science fiction writers that turns on ideas.
For example, a very simple story by Avram Davidson, about what happens when the U.S. government breaks a treaty with an Indian tribe, which is supposed to last -- per language in the treaty -- "as long as the sun shines and grass grows."
Davidson was a fine writer, but the story is mostly about its idea.
Implicit in Justine's remark (I think) is the idea that SF is about character and plot and style and mood.
I'm not sure any kind of fiction is ultimately about character, plot, style and mood.
Jane Austen's novels are beautifully written and plotted and full of wonderful characters, but what they are about is the English upper classes' blood-chilling focus on money, in spite of all their talk about morality and sentiment.
And they are also about the fact that women in the upper and middle classes have to focus on money, because they have no reasonable way to make a living. If they don't marry well, they will be poor.
These are ideas.
I suspect that any fiction which does not have an interesting idea at its core is not worth reading, except as entertainment. Not that entertainment is bad.
I don't think there are any ideas in P.G. Wodehouse, though I keep looking for one. His writing really is about his amazing skill as a writer.
And one could argue that producing concept free art is itself a kind of idea about art. "Look," Wodehouse says. "Art need not be about anything except a dazzling performance. It can be utterly pointless and still be thoroughly satisfying."
Finally, a personal note. I grew up around avant garde artists, and their art really was about ideas. Although I write popular fiction, my basic values are the ones I learned as a kid. Art should do something new. It should ask questions and push limits.