We are empty curved space

"The universe does not exist 'out there,' independent of us. We are inescapably involved in bringing about that which appears to be happening. We are not only observers. We are participators. In some strange sense, this is a participatory universe. Physics is no longer satisfied with insights only into particles, fields of force, into geometry, or even into time and space. Today we demand of physics some understanding of existence itself."

"There is nothing in the world except empty curved space. Matter, charge, electromagnetism, and other fields are only manifestations of the curvature of space. "

— John Archibald Wheeler: Physicist, coiner of the terms "black hole" and "wormhole," collaborator of Albert Einstein, and teacher of Richard Feynman.