Innocence is much more about a grown-up sense of loss than a precious quality of childhood. At best, our ideas about innocence evoke a pining sort of regret; at worst, they're used to make nostalgia a form of tyranny.
After all, it's a child's job to grow up, and so he's active every day trying to lose that innocence that he sees as keeping him away from adult freedom and power. Our attempts to preserve that child's innocence just reinforce his sense of powerlessness. This only serves to exacerbate his little rebellions, his need to prove how grown up he is.
Thus the child pushes himself beyond his limits, and conflict, confusion, broken bones—or worse—result.
Our grown-up attempts to keep kids innocent may arise from the desire to save them the pain that we felt as we lost ours, when we figured out how hurtful others can be or how to mistrust authority or how long it can take to salve a broken heart.
But it's inevitable: kids will cast off their innocence no matter what we do.
So how can we help them through the process? The classic answer is by observing and enhancing their play.
Play is how growing minds practice what they see as valuable to the world. So if we see a kid playing at war or painting, playing at spaceflight or engineering, we get a little peek into what she sees as vital to know.
Rather than being frivolous or silly, play represents that little bit of innocence that a child is trying, in a safe way, to work through. Maybe by engaging them there, we can calm our own fears, and help move children more easily into the freedom for which they long.