It's the oldest trick in the book -- write about having nothing to write, until something writable comes within view. Peter Elbow's "freewriting" makes use of just this idea, except that you write about whatever comes into your head, then glean the pile of text later for the themes for your next great oeuvre. The problem is, it's still a trick, and if your mind, being the resilient and adaptable mind that it is, clues itself into the fact that it is being tricked, then you simply get blocked at an earlier stage. Similar things happen with the piles of themes that you accumulate if the trick still works. Perhaps you can get a sentence out of them, perhaps more, but the ramifications trail off into impotence. Some kind of structure needs to be in place for the theme to take hold, and that may wither swiftly after its birth. In fact, for me, writing is one long motion paradox, in which all points are separated by infinitely divisible voids rather than embedded in continua. Sentences are possible, though the words are all hanging together in one glob of rubber cement, where any word can become a drop and fall off the page, sticking to your pants leg. It's corraling the damn things together into paragraphs, thematizing the paragraphs, binding the essay, and then having the audacity to revise -- there's where the trouble lies.