rationalskepticism.org

katja z wrote:

hackenslash wrote:

"I ain't got none" still conveys the same information as "I do not have any"

No it doesn't, because 'I ain't got none' contains a double negative, conveying the information that you do indeed have some (of what, who knows, but certainly not any linguistic ability).

Wrong. The difference between the two sentences is sociolinguistic - they convey different information about the speaker's social background and/or the situation of communication (its level of formality).

The double negative is the STANDARD and CORRECT way of expressing negation in many languages. It USED TO BE a standard way (not THE standard way as far as I know) in English, and in fact you can still find it in Shakespeare, where it simply expresses stronger negation than a single negative. In modern English, the double negative is outside of the norm (there are precise historical reasons for it), but it is still commonly used and understood in a number of dialects. Hack, it helps if you see languages for what they are - evolved, heterogeneous entities whose properties are explicable by their history. Using mathematical logic to explain certain things is about as helpful as trying to use a hammer to loosen a screw. Hammers are useful, but for screws you need a screwdriver.

Wiki wrote:A double negative occurs when two forms of negation are used in the same sentence. Multiple negation is the more general term referring to the occurrence of more than one negative in a clause.

In most logics and some languages, double negatives cancel one another and produce an affirmative sense; in other languages, doubled negatives intensify the negation. Languages where multiple negatives intensify each other are said to have negative concord. Portuguese, French, Persian, and Spanish are examples of negative-concord languages, while Latin and German do not have negative concord. Standard English lacks negative concord, but it was normal in Old English and Middle English, and some modern dialects do have it (e.g. African American Vernacular English and Cockney), although its usage in English is often stigmatized.

Merriam Webster Usage Dictionary wrote:double negative noun
plural ∼ -tives
[count] grammar : a clause that has two negative words (such as “nothing” and “don't”) when only one is necessary ◊Double negatives are usually considered incorrect in English.
▪ “I didn't do nothing” is a double negative. If you want to be correct, you should say “I didn't do anything.”