There are three types of double negatives: not plus a negative adjective, a negative verb such as ain't and a fuzzy error, which is when people don't know how to handle negatives. People say that double negatives are confusing and thus are considered to be illogical. Those people usually consider mathematics to be logical and so the would enforce mathematical rules to language. This is illogical because if two negatives equal a positive then ' not untrue' would render it to mean 'true.' So having thee negatives would equal out to be a negative, which in language terms would mean that ' I didn't give nothing to no one' would be negative, but which part of the sentence would cancel out? When using negatives, the point that someone is trying to make is a denial of something. For example, 'you ain't going to heaven' implies that this person is denied going to heaven. People don't want to think about whether something is positive or negative, the thought process is too deep. They just want to get their point across and move on. Many different languages follow the same pattern of the double negatives and this dates back to the eighteenth century.