At some point in our lives, early on, maybe in grade school, teachers give us a pat definition for a sentence — “It begins with a capital letter, ends with a period and expresses a complete thought.” … But that definition misses the essence of sentencehood. We are taught about the sentence from the outside in, about the punctuation first, rather than the essential components. The outline of our [sentences], the meaning of our every utterance, is given form by nouns and verbs. … I like to think of the whole sentence as a mini-narrative. It features a protagonist (the subject) and some sort of drama (the predicate): The searchlight sweeps. Harvey keeps on keeping on. The drama makes us pay attention. [Italics and bolding added for emphasis.]This, I think, points to the problem with most definitions. Saying that a sentence begins with a capital letter, ends with a period and expresses a complete thought is the very least that we can say about a sentence. The very least.
And our students know that. They know that this definition says next to nothing, and most of them wisely ignore it, or if they do force themselves to remember it for the quiz at the end of the week, they ditch it at the classroom door immediately afterward. Wise them. They know that this definition will never connect them to good writing, to the magic that lies at the heart (the middle) of crafting a beautiful sentence. Or even a functional sentence. Students know that if they really want to learn what writing is, then they have to learn it from the inside out, the way they learn video games. They learn Skyrim from the middle, and they have to write from the middle. The above definition separates them from writing. Who's interested in that?
You also have to define from the middle, and maybe soon I can actually start doing that.