Mass, Spin, Charge, Hair

God, my head. No two twins
Could be as much the same

As—God!—my head and me.
Bald as black holes once were

Thought to be, head and me.
That’s not for lack of hair.

In fact, like some black holes
We have a few wild hairs,

Some few facts left for us
Right at the edge of us

Where my head, God, my twin
And I, might not, are not,

Quite the same. One deep rule
Holds in all times: no two

Can be, in truth, the same.
When you prove this, you solve

And merge all sorts of things—
Are heads facts? Have holes strings?

But that’s you. I can’t prove
This—God! My head, not me!