I copied down the following years ago from a photograph of sketches on the wall of Philip Guston’s studio (plate 70, specifically, bet. pp. 178 and 179 of Night Studio: A Memoir of Philip Guston, by Musa Mayer, Penguin, 1988):
I hold my inventive capacity on the stern condition that it must master my whole life, often have complete possession of me, make its own demands on me, and, sometimes for months together, put everything else away from me. […] Whoever is devoted to an Art must be content to deliver himself wholly up to it, and to find his recompense in it.
Guston wrote out the above in all caps; his attribution was simply DICKENS. (Here, for the moment, is a JPEG of the photo.)
What’s skipped over by that ellipsis is really interesting, though. The quote comes from a letter Dickens wrote in 1855; I might be terribly wrong, but I think the gist of the letter is “sorry, I can’t see you, I’m really busy.” Here’s part of the ellision:
“It is only half an hour”—”it is only an afternoon”—”It is only an evening”—people say to me over and over again; but they don’t know that it is impossible to command one’s self sometimes to any stipulated and set disposal of five minutes—or that the mere consciousness of an engagement will sometimes worry a whole day. These are the penalties paid for writing books.
—from p. 584 of The Letters of Charles Dickens, Vol. 7, 1853–1855 (Graham Storey, Kathleen Tillotson, Angus Easson, eds., OUP, 1993)
Which reminds me of this:
Writing is a deep-sea dive. You need hours just to get into it: down, down, down. If you’re called back to the surface every couple of minutes by an email, you can’t ever get back down. I have a great friend who became a Twitterer and he says he hasn’t written anything for a year.