There are some who believe, perhaps unwittingly, that to concern oneself with points of grammar is to worry over matters of social etiquette: learn the rules, apply them, and don’t ask why. If that were true, if our speaking and writing were only a matter of dictates, of absolute laws laid down absolutely, the prospects would be dark indeed. Who in their right mind would care to slavishly learn and follow rules for which no reasons can be convincingly given?
The subject of grammar, however, with all its many intricacies, is better understood as one of a number of arts which together allow us to have a voice, to become aware of ourselves and others. An art is a skill, a way of doing something; it is a system, an organized body of facts, a collection of procedures which, once learned, give us together a way to say accurately and persuasively what we see in the world and in our minds—all to the end of expression, a word often terribly misapplied in understanding just what art is about. If we can think about grammar as one of the arts of language (logic and rhetoric being the others), we will be able to work more patiently through the patches of stonier ground that inevitably make up part of any study we would ever care to apply ourselves to.
If the word expression is often misunderstood, so too is the word rule. A rule in the language arts is not a regulation, not something imposed but something recognized: if you use this word, then your reader will think this; if you put that phrase here and this clause there, then you will have this effect on your reader, not that. Rules in grammar are the crystallizations of how we have come to use a language; they are rules of engagement, so to speak, agreements that we have made together about the way we will act in language so that the work of understanding is not unnecessarily difficult. A rule is a direction (that, in fact, is its linguistic derivation), a guidance to avoid confusion and better assure mutual understanding.
But rules change, and here we come to the tricky trouble of studying the rules of grammar. Language is not a static, unchanging reality; it changes as its speakers and writers change, as we see new things, find unrecognized assumptions in the ways we have been using our language, and as we come to a better understanding of ourselves, our actions, and our engagements with the world. Change is not the problem, but change to no common purpose is. Change for the sake of change alone is very difficult to distinguish from an idiosyncrasy, something we do because we wish to do it, a peculiarity of ours alone. And peculiarities, even, are not the problem, for how bleak and unjoyful the world would be without the dash or distinction or flare that each of us could and should bring to our time.
To speak of the rules of grammar, though, is to speak about the rules of the common language, the way it can be used most widely by most people about most things to keep us all together. That there is a way we use a language in common means we believe we stand in common about certain realities, that we share some degree of agreement about a certain level of reality, that we can say things that are true and things that are not. And this is why change must be reasoned change. Change there will inevitably be, and rightly so. But rules, old or new, cannot be impositions; they must represent points of justifiable stability amidst all this inevitable change in the way we organize the elements of our living language. They are means, not ends, sometimes to be observed only theoretically, but always, in the larger interest of a shared life, necessary as a measure against which to accept or reject a change we’d like to make. Rules in the art of language are best understood as a standard, a moving target—but a target nonetheless.