i'm ripping this directly from isolde's post on thelifeuncommon:

"I guess what I’m saying is that as a writer you are a creator, so, in that sense, what are a creator’s responsibilities to the things she creates?  Life, wholeness, realness?  Or as a creator do I have a right to just leave things half formed, deformed, or partial?  If you love a character, or believe in a character, shouldn’t you take them as far as they can go?"

she raises a really excellent question—what are my duties as a writer?  especially to the characters i've created, because they, like real people, have unexplored potential, have hidden problems, have secrets.  and to the non-writer, it sounds so stupid—isn't the writer making it up as they go along?

yes and no.  you make up some things, and create them into a character.  but then, in aristotelian truth, a thought becomes an act, which in turn becomes a habit, which becomes behavior, which eventually formulates character.  you have to have all of those things—thoughts, acts, habits, and behaviors, in line and matching so that the character is sound and valid. 

so how far do you go?  how deeply do you question, discover motives, flaws, potential for better qualities, like heroism and bravery?

my only answer is as far as you possibly can.  what you can frame in the story becomes a much different question, but you have to know these characters like you know yourself—and inevitably, like your own mind, your fears and triumphs will most likely shock you.  the darkest things you keep hidden will be the most difficult and yet transcendent to uncover. 

writing is nothing if not a constantly fluctuating journey.