As one of the Six Core Competencies, you’d think theme would be some complex monster of a literary theory, just like character or structure.
In execution, though, not so much. At least, not always. As I said in the previous chapter, if you have complete control over the character arc in particular, theme can sometimes take care of itself. You don’t have to have an agenda to speak to the truth of life, you simply need to explore and illuminate through the experiences of your characters and the consequences of their choices.
Then again, you can turn your story into a soapbox, which you can mount to preach your truth to the world, too. The risk of that is to brush up against the fine line of propaganda, but frankly it happens all the time in published books and produced films.
Theme in any story is analogous to health in our daily lives — the abundance of it vs. the lack of it defines how well we function. A state of health — and theme — is always present, good or bad, valued or not. Bad health leads to a compromised life. A lack of theme leads to a compromised story.
And that’s the point. The more you value and cultivate the themes in your stories, the better those stories will be. If you’re pursuing mediocrity, go ahead and allow theme to take care of itself. Depending on the type of story you are writing and the nature and depth of your character arc, this may be a perfectly workable strategy.
Thing is, you’ve got to be really good to pull this off.
On the other hand, if you want your story to take a position on an issue, you need more than a character arc to pull it off. And, by the way, you have to be pretty good at this to make that work, as well.

The excerpt is retrieved from the book ‘Story Engineering’