To write upon nothing

I am now trying an experiment very frequent among modern authors, which is to write upon nothing, when the subject is utterly exhausted to let the pen still move on; by some called the ghost of wit, delighting to walk after the death of its body. And to say the truth, there seems to be no part of knowledge in fewer hands than that of discerning when to have done. By the time that an author has written out a book, he and his readers are become old acquaintance, and grow very loathe to part; so that I have sometimes known it to be in writing as in visiting, where the ceremony of taking leave has employed more time than the whole conversation before.
Jonathan Swift

pindaro