Passive Voice and Double Negatives
I was a tutor for English, but I thought I had left that far behind. Now I go to a meeting of my Sociology class and am lectured about active and passive voice.
For those who didn't pay all that much attention the first time around, "passive voice" is a syntactic structure involving "to be" verbs (be, being, are, is, am) whereas "active voice" involves the verb directly. For example:
Passive: I was running.
Active: I ran.
Now, there is a reason why English teachers focus on this like a drunk man focuses on finding his keys: Active voice has a nice, vibrant quality; people are doing things or things are happening rather than things just being there; and active voice (as you can see from the above) is often superior in brevity.
But there are no hard and fast rules in English. Contrary to what you've been told, there are times when someone would want to use passive voice. For the reader's convenience, they're numbered.
1) Finality: Sometimes, in order to communicate that a circumstance is static, permanent, perhaps in the past, one would use passive voice. For example: "He is dead." rather than "He died." The former communicates the unbreaking reality of it.
2) Authentic Dialogue: This should be a no duh, but beginning writers often forget it. Your dialogue shouldn't sound like an essay. It can obviously be unrealistic in a literal sense (no one in Shakespeare's time spoke in strict iambic pentameter, and no one will ever speak like in Star Trek: The Next Generation), but it should sound authentic, and one way to make it sound authentic is to have sentences in dialogue that are not strictly grammatical.
3) Softening of the Message: Sometimes (and this will come up in the double negative discussion too), you don't want a sentence to have all the impact it can get. "Bush is killing people" and "Bush kills people", though identical in strict terms, have different connotations and imagery, and would be used in different contexts and for different implications.
The same thing happens with double negatives, such as "I'm not not happy." Why would someone use it?
Well, because "I'm not a bad man" isn't literally or connotatively identical with "I'm a good man". If you want to soften your message, you use double negatives. Language isn't math.
And the lesson to be drawn?
Maybe that our schools don't stress real understanding but irrational compliance with easy memorizable rules?
I dunno. Probably nothing.