  In addition, there is a widespread pragmatically motivated tendency for a formal contradictory negation to be strengthened to a semantic or virtual contrary through such processes as litotes (“I don't like prunes” conveying that I dislike prunes) and so-called neg(ative) raising (“I don't think that Φ” conveying “I think that ¬Φ”). Similarly, the prefixal negation in such adjectives as “unhappy” or “unfair” is understood as a contrary rather than contradictory (not-Adj) of its base. These phenomena have been much discussed by rhetoricians, logicians, and linguists (see the entry on negation and Horn 1989: Chap. 5).