Hornsea Writer, Penny Grubb, takes a look at something that F Scott Fitzgerald once said about why writers write:
“You don’t write because you want to say something. You write because you have something to say”
and asks as she unravels it, if Fitzgerald is on to something that all writers ought to bear in mind.
Putting it more pragmatically (and less poetically) she suggests that if you can't sum up your novel in a sentence, then you might not be clear enough about what you are trying to write.