Double Negatives

Logic don't enter into it.

   "Don't use no double negatives," some teachers and self-appointed editors insist, because "two negatives make a positive."
   That may be true in mathematics, but not in language. In some languages, moreover, most notably in French, double negatives are required in a sentence.
   "But that's not logical," you say, and that would be correct. Logic and mathematics use language to express logical concepts. but language itself is not logical.
   There are better reasons for not using using no double negatives. One is to avoid confusion and increase clarity by speaking directly to what is meant. That, however, does not stop lawyers from using double negatives in their writing. Indeed, it may be a reason why they do.
   A second reason would be social, in that some dialects of English that often use double negatives have less prestige than dialects that avoid them. That, however, is a social judgment, not linguistic.
   The only reason some dialects have more prestige than others is that its speakers have more prestige.
   The lesson, then, is for writers and speakers to know their target readership and audience. Speak to them, not at them.