Just to offer an expansion on Stormy’s last post:
In semiotics and audiovisual narrative you are taught to create meaning by opposition between things.
If Batman is dark and silent, the Joker is colorful and noisy.
If the Joker kills, Batman doesn’t.
Who is Batman? What the Joker isn’t.
Who is the Joker? What Batman isn’t.
If you don’t define oppositions, you have no dialectic in your story. If there is no dialectic, you have a story that can’t move organically, and as such, a boring story.
In less film-y terms: You know what cold is, because you know what hot is. And vice-versa.
Sense and meaning appear from opposing things to what they are not, and not from just restating who you are:
It is not what we are underneath that defines us, but what we do [that the villain doesn't] that defines us.
Thank you, Batman.