Not, rather

I am what is when you don’t notice.

You notice when it’s not me – when my absence is too much your eyes squint; you reach for a hat, or sunglasses, or use your own hand if I leave quickly.  You notice when my absence is so complete; well, you would, if you even knew what that was like – so complete that your ancestors reached, groped even, for a lantern.  Not that they had one.  Or knew what a lantern is.  But you?  You don’t know the complete absence of me

 – you have filled the void entirely.  

and

The Void holds what you need.