A visit to the many prescriptive grammarians who hang out in the blogosphere in order to save English from its speakers will establish what you knew already: your fourth grade teacher disapproved of double negatives.

Double negative equals a positive. It is a truism of traditional grammar that double negatives combine to form an affirmative. Readers coming across a sentence like He cannot do nothing will therefore interpret it as an affirmative statement meaning “He must do something” unless they are prompted to view it as dialect or nonstandard speech. ¹

Your fourth grade teacher may well have been kind, helpful, and truly concerned that you got an education, and from that person you will have learned that in English, two negatives make a positive and thus that I don’t want none in fact means, please mother, pile those mushy canned peas even higher on my plate.

You were probably ten or so when you were first scolded about this, and given the underlying algebra to guide you into the light of grammatical goodness. ²

At ten, you probably hadn’t got so far in math class, so the two negatives make a positive rule would have meant as much to you as colorless green ideas sleep furiously. It sounds good, but there’s something missing — oh yeah, meaning. Of course, so much of what you were taught in fourth grade made no sense, you most likely just nodded politely and chalked it up to adult silliness.

Once you did get far enough into math and understood the origin of the two-negatives-make-a-positive rule, it was too late to go back to fourth grade and ask for clarification.

Miss Lack, if two negatives make a positive, what do three negatives make? How about five? If my mom says ‘I told you to never never never never never disturb my colorless green ideas when they are sleeping,’ does this mean I can poke her colorless green ideas with a stick, sleeping or not, whenever the urge takes me?

If this occurred to you at some point in your schooling, you discovered the limitations of the two-negatives-make-a-positive rule on your own. Most likely it didn’t occur to you, simply because you had heard the rule too often, and absorbed it into your social-grammatical self. Despite the fact that you hear multiple negatives all the time and understand them without resorting to a calculator, despite the fact (as you will learn in French class) that other languages revel in double, triple, multiple negation strategies and survive, even despite the fact that you can appreciate Bob Dylan, who knows a good double negative when he sees one — even after all that, if you do catch yourself using a double negative, you will still look over your shoulder in fear that Miss Lack is standing right there, ready to pounce.

The absurdity of the In-English -two-negatives- make-a-positive logic is there for us all to enjoy, but first you have to shake off the shackles of the grammar police.