Writing a novel is hard. This will come as no surprise to anyone who has ever done so (or if you have, and this is a surprise to you, please do not tell me of the ease with which your prose lept upon the page. My poor, fragile ego will not stand it.). I like a good challenge, me, so I like to throw additional difficulties into the process.
I'm currently - if you are a very generous person - revising. Anne Lamott, in Bird by Bird talks about the need to write a shitty first draft. Let me tell you: I got that one right. Basically, I threw tens of thousands of words at a notebook and checked to see what would stick. Characters changed their names, their professions, died, and resurrected. (In at least one instance, I didn't notice that I'd brought someone back from the dead until I reread the draft.) And those aren't even the biggest changes I'm making.
Because I write by my headlights, because I believe that outlines are Satan's traps for the unwary, I don't know what is going to happen in the book until I need it to happen. And I'm fine with that generally, because plot is the last thing I care about in a book. What happens? Meh. But to whom does it happen? and what does it mean that it did? Those, those things I care about.
For me, the "to whom does it happen?" is the question that begins the book. I need a character I care enough about to begin writing. "What does it mean that it did?" - the thematic question - is the question that organizes the book, that is the reason why I am writing it. Unfortunately, I sometimes (as in this case) need to get to the end of a draft and have the general idea of what happened, before I can find the thematic and emotional through lines that carry the story.
The problem is, without that thematic through line, without some idea of why I am writing this book, what the larger purpose of the story is (and yes, I know that sounds like such an English professory sort of thing to say, but I am an English professor, and one who knows what kind of story she wants to read, and what kind of a story she wants to write) it is very easy for me to stop writing. It's easy to feel like the book isn't working. Because it isn't, not yet. I'm writing without having all the pieces.
For me, right now, that's the hardest part - to keep writing, without all the pieces. To trust myself enough to know that I am leaving a breadcrumb trail and that the ravens won't eat all of them before I find my way back. To let the shitty first draft be a map - one that marks the edge of the world, and says "Here there be dragons" but has compass rose and key all the same.