There are things within any given story that you, the reader, don't see and never will. Sometimes these things are vital to the story, sometimes they're just little nuggets that might be interesting to know, but you never will and you won't (I hope) feel cheated for not knowing them. A lot these unseen bits of background details come under the cleverly titled heading "Back Story" (at least that's what I'm told it's called by those who know such things. I don't t do this for a living, and I haven't taken a class in writing in many, many years -- hopefully that fact doesn't show too badly). You the reader are aware -- at least you should be aware -- that this unexpressed detail is floating around somewhere, and you hopefully have faith that someone in charge of this world you're reading about knows about it. As I've noted before, I'll be damned if I'm confident I'm always in charge.
So Letoria, just what the hell are you talking about?
Let's take a look at my "Novel" Karen and Laci. There are unmentioned things in the background that are absolutely vital, or we'd have no story, things I know but you never will. For instance, the character Laci -- just who the hell is her father? She has a nasty skank for a mother, yet Laci herself is beautiful and intellectually gifted. That damned sure didn't come from her mother. When you look around what I call "Laci's World", most of the men are thugs, drunks, junkies, and bums, sometimes all rolled into one convenient package, the dregs of the welfare society. See that tatted up dude with the buzz cut, goatee, 10,000 piercings, flat-brimmed ball cap cocked at an angle under his dark hoodie, pants half-way down his ass, swaggering and bouncing up the street, grabbing at his crotch every third step? Is he going to produce a Laci? Well, genetic mutations do happen, or else Darwin was full of crap, but I wouldn't count on it.
So where does she come from? Well, I know. I know who her father (or maybe the word "sire" is more accurate) is. I know exactly how her mother got pregnant with Laci, I know why her mother, the inimitable Sandra, didn't have an abortion, and why Laci was the only baby she brought into the world, even when babies were a form of money. You'll never know any of this. Why? It's not that it isn't relevant to the big picture of the story. Clearly it is. It isn't however, directly relevant to the story that's unfolding before you. Strictly speaking, you don't need to know the details. Besides, how can I pass this information on when no one within the story knows it? Laci doesn't know who her father is. Even after an extended period of sobriety, Sandra could only make a half-assed guess, and it's highly doubtful she even remembers the actual encounter. The father has no clue he sired a child, and there's no reason to expect he ever will know. So how could I tell you?
I can't, so you have to make up your own details. I try my best to give you that opportunity.
We can make more or less the same observation about other details - how did Karen and her ex-husband meet, what's Laci's favorite color (pastel pink, if you must know), to whom did Karen lose her virginity? They're details you don't need to know, nor are you likely interested in them. I know these details, because I have to. The more real and complete she is to me, the more likely it is she'll be real and complete to you. And she is real to me, you know. As real as I am to myself.