[jcranmer]

Double negatives are grammatically correct English. Consider the sentence, "I do not think that course of action would be unwise."--that is a double negative, and I know of no one who thinks there's even a hint of problem with that sentence.

One facet of double negatives is that the English sense of negative + negative = positive isn't universal. In French, double negatives remain negative; consider "Je ne sais jamais rien." The literal translation is "I never know nothing," but the correct translation into English is "I never know anything."

[kharms]

>"I do not think that course of action would be unwise."

That's a funny example, as it can be read both literally ("I like it."), and passive-aggressively ("I don't dislike it."). So while double negatives might not be grammatically incorrect, they are often ambiguous.

[chrisseaton]

> That's a funny example, as it can be read both literally ("I like it."), and passive-aggressively ("I don't dislike it.").

You seem to have those backward.

"I don't dislike it" is what it literally means. That's the opposite of being passive! "I like it" is reading an implication which isn't literally there and is more passive.

There'a a really important difference here. Someone can not think that something is not unwise, but that does not mean they think it's wise. A double negative does not cancel out - you loose important literal meaning when you do that - not even just an implicit idiomatic meaning.

[toasterlovin]

This is the kind of stuff the makes writing an art form.

[WalterBright]

A double negative in English often is used for emphasis, not to create a positive:

"Not no-how, not no-way!"