This isn't a comprehensive categorization and it might also be a tautology, but perhaps it's still useful or relatable:
In my reading, there are novels that hypothesize about how the world could be, taking a culture you participate in, honing it down to something fundamental, and then showing how that world might run. And then there are novels that take you somewhere independent of your experience.
Hypothetical exploration vs the distillation and clear articulation of what already exists.
Like I said, these two categories very well might overlap in practice as a novel is always something independent of your experience, but also -- if you're an appropriate audience and the writing is any good -- couched in what is, what exists.
A Farewell to Arms, read in 2018, by someone who knows nothing of war and who lives a comfortable life, cloistered in a culture that dismisses the majority of suffering as antique and what's not as impolite, is an effective study of what it is to be a stoic. To be a true stoic, faced with inevitable, personal, and absurd suffering, and to take responsibility for it, regardless. That is Hemingway's character, to me. To contrast that character against the modern day glutton, lazy, and unaffected (i.e. me), is a powerful thing and worthwhile thing to do.