Two thoughts were brought to mind by this discussion:

1. There seem to be two schools of thought about grammar in general. One school puts the rules first and usage second; the other considers usage paramount and feels rules should always submit to common usage, which may be the simplest way of conveying a simple idea to another.

The people in the first group often consider those in the second group uneducated boors, and the second group frequently considers the first group to be out of touch snobs.

While I proudly consider myself part of the first group, I don't consider myself a snob; I simply love the beauty, subtlety, music and magic of language, and marvel in its form. I revel in finding the perfect word or case or combination to convey a particular shade of meaning. If someone considers language nothing more than a blunt tool for expressing basic thoughts, that is their prerogative, and I respect that. I happen to share their belief that getting your thought across is the most important thing, so I will subtly filter my speech, depending on whom I'm speaking with, and will gladly break grammatical rules if it helps to express a thought. That is one of the beauties of language; it can be as flexible as the speaker.

Having said that, I confess I do rue the erosion of simple, basic rules of grammar, which often does have the effect of watering down the subtlety of communication. For example, the case of Past Perfect seems to be rapidly becoming archaic. Many English speakers, particularly from the South, use the Past Tense (Preterite) conjugation when using "had" before the verb (Past Perfect tense). I know many educated speakers, particularly from the South, who will blithely say "I had WENT to the store". When asked about this, the most common reply is "But I had GONE to the store just SOUNDS wrong". This brings me to my second point.

2. I am a musician, and language, like music, was played (spoken) before the rules were codified, not the other way around. Unlike music though, language is not based on the immutable laws of physics (sound vibrations). The laws of music theory have no exceptions, any more than the Sun sets in the east sometimes. Language, however, is simply a product of our human minds, and so is subjective and constantly changing. The English we speak today is quite different from the English spoken 200 years ago, in the post-revolutionary US, and vastly different from that spoken 500 years ago, around Shakespeare's time. This change occurred, not in the grammar books, but on the street. This is a hard fact for many grammarians to accept, witness the Académie Française, which attempts to keep the French language "pure". This is a joke; you cannot "regulate" language. It has a life of its own, and will morph and evolve regardless of what any institution tries to impose upon it.

By definition, the way that a language evolves is by common usage, which will break whichever "rules" it wants, and then some future grammarian will come along and codify the new rules. You know a rule is archaic when a majority of native speakers, upon hearing an example of the old rule declare: "It just SOUNDS wrong".

This is simply a fact of grammatical life; a kind of "mob rule", if you will. It's up to each of us to find our own comfortable position on the continuum between the snobs and the mobs!