Q From Trevor Williams, Essex, UK: Is it wrong to use dichotomy to mean a puzzling contradiction? If so what word could be used instead?
A Many commentators on language and many readers of World Wide Words will unhesitatingly say you can’t correctly use the word in that way. But there’s plenty of evidence that it is used with that meaning. It’s a classic case of a word with specific technical senses in logic, astronomy, botany and zoology having been taken over by writers who have only a hazy idea of its meaning.
It comes from the Greek dikhotomia, a splitting into two, and in English it originally referred to a division into two strongly contrasted parts. For example, in logic you can argue that an object is either red, or it is not red; this division is a dichotomy in its strict sense. Writers quite early on started to use it for anything divided into two parts or resulting from such a division, or for situations in which a strongly marked difference of opinion existed. This evolved into the sense you describe, in which the division results in a situation that is paradoxical or ambivalent.
The best discussion of the issue is perhaps that in Merriam-Webster’s Dictionary of English Usage, a book I unhesitatingly recommend. The editors remark that the current meaning is hazy, to the extent that it is not only difficult to give usage advice, but even to describe accurately how the word is being used, as in this example they quote: “the Eskimo today lives in a dichotomy, in a kind of cultural and economic never-never world”.
Their conclusion is worth quoting in full: “In many cases of such dichotomizing, the message that gets across to the reader is chiefly that the writer is using a fancy, academic-sounding word. If this is the impression you want to convey, dichotomy will surely serve you. If you are mainly interested in having your sentence understood, however, you might be better off finding another way to word it”.
That other way might well include ambivalence, split, division, paradox, or schism. Or perhaps your own words, puzzling contradiction, if that is what you mean to say.