从双重否定看英文语法
《向学习英语者讲话》(Hints for Leraners of English)是论述学习英语的37篇文章的一个合集，“每篇揭示一个或两个问题，大都是英语语法书和英语修辞书不曾讲到的。内容谈到什么读物是初学者需要的读和什么是不宜读的; 怎样才能读的精细；... 以及拘泥语法条条，一概类推所造成的错误的问题。”
葛老在第十篇谈到了“双重否定”的问题: Double Negative in Current English. 他说:
An English editor of a famous classic says in his notes to the book:"Double negtives in Elizabethan grammar amount, not to an assertion as they do in current English, but to an emphatic negation"
在伊丽莎白时代的文学中，双重否定并不像当代英语中那样等于一个肯定，而是一个加重语气的否定。
又说:
Double negatives used as an emphatic assertion may be said to be found in current English, unless by current English is meant English current among educated people alone.
There are serveral English usages that every learner of English should know, but which many, or even most, Chinese learners do not know, because these are not to be understood by means of mere logic and are not to be found in ordinary grammars.
这让我想起我曾经写过一篇有关双重否定的文章，再贴出来分享给你。
Double negatives occur when two forms of negation are present in the same clause. They are acceptable in many standard and non-standard dialects and foreign languages. When this occurs, the second negation intensifies the negativity of the sentence as a whole.
“双重否定”在口语中常被用为强调，而不是“双重否定表示肯定” -- 这种用法被很多人认为是unacceptable, non-standard，应该避免使用。正如我们之前讨论的关于ain't的用法一样, 地道的不一定是标准的，不标准的不意味着就是错的。作为语言学习者的我们要“海纳百川", 知其所以然，然后选择性的使用, 以免弄巧成拙。
从语法的角度来看这个问题。语法可以分为prescriptive 和 descriptive，Prescriptive grammar 就是语言专家们总结的一套语法系统, 就是“死语法”, 也正是我们在学校学的那种。而descritipive grammar 是语言是如何真正的被使用的。
葛老说:
...there are many ungrammatical expressions that are worth knowing. You ought to learn to use English correctly. But you ought to as well to learn to understand the incorrect expressions that are common among Englishmen or Americans.
Specialists in descriptive grammar (called linguists) study the rules or patterns that underlie our use of words, phrases, clauses, and sentences. On the other hand, prescriptive grammarians (such as most editors and teachers) lay out rules about what they believe to be the “correct” or “incorrect” use of language.
这也许就是英文学习者经常吐槽的原因吧 -- "书本上学的东西不实用" “过度强调对错"。 我们一直接触的都是prescriptive gammar: 要记住什么时候用which/that, where/ in which 这种。
在语言的学习过程中, 我们要注意这种语言的"对/错" 还有"存在即合理" "适当/不适当"。有一些问题本身就是很有争议的, 所以我们语言学习者要多观察总结，听听不同意见, 少一杆子打死。学习语法的目的不只是去学习语言的条条框框，而是学习如何分析一门语言, 从不同的角度去解读语言现象。
我们看一下双重否定在英文中的使用：
在美剧Gotham第13集中:
例如大家都熟悉的一首歌, 潘玮柏和苏芮的那首《我想更懂你》, 在歌曲之前有一段英文对白, 你会听到潘玮柏说:
Stop acting like you care about me
Stop acting like you wanna know something about me
You don’t know nothing! you don’t care! Stop asking!
In Standard English, however, double negatives in a single clause cancel each other out and transform the meaning into a positive.
当然了有时候双重否定是故意的，例如She is not unattractive 不全等于 She is attractive. 例如我们经常说的"I couldn't care less".
找了一些图片, 感受一下：
今后如果你碰到double negative的“被部分人认为是错误的”用法, 我们知道就好了，自己要慎用。
问题来了，How about a triple negative?
葛老说:
Important as grammar is, there are many turns of expression that are generally considered blameless English though they are not quite defensible from a narrowly grammatical point of view. So that the mastery of English grammar in its narrow sense does not enable one so much as to read English intelligently.
学语言要有一个开放的语言关，读懂一个句子理解一句话除了需要了解语境外，还需要注意一些超语言语境的地方，这就需要我们了解一下语言背后的文化，有点幽默感。