I mentioned, a few posts ago, that I was about to send off a "finished" novel to my agent, and a few people wondered how I knew it was done. This is a pretty common question among writing students, too, for a very simple reason--nobody has ever managed to answer it adequately. And I'm not going to be able to here, either.
In a sense, the answer is simple--it's finished when you decide it's finished. Then, having made the decision, you "know" it to be true. But the objective truth, if there is one, is much more complicated--it depends on what we mean by "finished." Do we mean that the work is in its final state, on a bookstore shelf, ready to be bought? Perhaps--but Henry James is famous for rewriting all of his early published works, and I can think of several contemporary writers who have issued "director's cuts" of some of their books.
So maybe it's only really finished when the author dies, right? After that, it can't be changed. But of course we know, from the history of such long, complicated books as Ulysses and In Search Of Lost Time, that death doesn't bring the work to a close either. There will be different editions, complied by various scholars, based on various notes, statements, or secondhand recollections of the author. We were just complaining a few weeks back about the "unexpurgated" Carver stories now making their way into the public eye.
This is all kind of beside the point, because the real question was about how a writer--that is, me, or you--knows when to stop writing. But it's worth seeing the big picture first. A book is never finished: that should be at the forefront of the writer's mind. Once you've accepted that, you can confront the utter arbitrariness of completion, and just push it until you can't stand it for another second.
Who was it who said a book was done when you started putting back all the commas you removed in the previous draft? Probably a lot of people. It's a decent rule of thumb. You're finished when you become paralyzed by indecision. Of course, even that's not the end, because six months later, you'll be a different person--a person who will see the manuscript differently, and perhaps will have a clearer sense of what to do.
If you're lucky, though, the book will be published by then, and it will be too late. Because this process is agonizing, and sometimes you need to cut your losses and move on. You have to take what energy you have left and plough it into the next project--maybe that one will be the one that turns out perfect on the first try.
For me, personally, I have several "dones." There's the end of the first draft, where I have for the first time a complete, semi-coherent piece of work. Then there's the end of draft three, when I usually decide it's ready for Rhian, Ed, or another friend to read. Draft four or five goes to the agent, and maybe six or seven (if I've managed to get it accepted for publication) goes into galleys. And then there's the published version, which, for all practical purposes, I consider really done. This system does indeed help me know when I'm through--if I'm reaching draft three, for instance, it must be "done," by definition. The system creates artificial mental deadlines, which I force myself to meet, regardless of how incomplete the work is. Then I'm finished because it's time for me to be finished.
That said...I was paging through Mailman, my fourth novel, the other night, and I came across at least half a dozen sentences the current incarnation of myself would never allow to make it into print. Maybe someday...
Nah. I'm done.
PS: a note to the dorks out there...I'm posting this from Ubuntu Linux, which I just installed on my laptop. I recommend it--it has been way easier to set up than Vista was a few months ago, when I tried configuring Rhian's machine. If you're into open source, public domain, and all the other ethical systems that foster creative innovation, you might dig doing your writing in this environment.