If you have me, you have two of me. If you have one of me, you have none of me. What am I?

I climb when you’re clever, I sink when you’re rude, Yet ever capricious, I'm shaped by the mood. I underlie your words, whatever your view, My home framed in arrows, the choice left to you.

I am the chisel that reveals the statue by taking away. I am the silence that gives the note its purpose. My presence defines all that is here, yet I am not here at all. If you were to name me, you would have to speak of what is not.

I am a silent order, a secret in a square, No twin may wander, yet all must be there.

My rhythm is a mystery, many have tried to decipher, but my identity is known only by me and one other. The opposite of artificial, part of the whole. All hidden in plain sight, except for one.