"Or vice versa".

In his prologue to his 1979 book Teaching as a Conserving Activity, Neil Postman wrote about writing Teaching as a Subversive Activity which he had written ten years earlier with Charles Weingartner:
For every idea we expressed as "true," we could easily think of its opposite, or at least of some alternative, as also true. It was as if we and our shadow were looking at the matter from opposite poles; our right was his left, his right our left. We understood which way we were facing but it was not hard for us to imagine others, or even ourselves, facing in another direction. As a consequence of this double vision, Charlie suggested early in our collaboration that the last sentence of each of our books should be "Or vice versa."
Though Postman was no great fan of hypertext, to my mind there's something inherently hypertextual about this approach. When we commit something to paper, we take a stand. But often we also know that the same arguments that brought us to our present opinion, were they to be slightly differently organized, might have led us to an opposite position. Linking, though essentially nothing more than a technical tool for connecting two entities is capable of giving expression to the ambivalence that seems always to be just below the surface of the seemingly definitive positions that we take. It was perhaps this hinting toward ambivalence that Steven Johnson noted in his discussion of Suck magazine.

Go to: Vanilla-flavored linking, or
Go to: The incredible shrinking directory, or
Go to: Dr. Hierarchy and Mr. Associative