Abstraction

Idea.
There are three types of stories. One you tell. One you read (hear). The last you remember.

Without reading Proust and judging only by the title of his opus, I'd say he focused on the last. His brilliance was in evoking the memory of the story.

We spend lots of time in school thinking about the second.

But I think it's only when we've lived long enough to repeat our stories a few times (with years in between) that we can really reflect on the first.