Boundary

What has happened here will do
To bite the living world in two,
Half for me and half for you.
Here at last I fix a line
Severing the world's design
Too small to hold both yours and mine.
There's enormity in a hair
Enough to lead men not to share
Narrow confines of a sphere
But put an ocean or a fence
Between two opposite intents,
A hair would span the difference.