What is in David’s head?

What is in David’s head?, 2023

Carrara marble, print on Rauch film translucent paper; size varies according to the site

Michelangelo said, “The sculpture is already completely present in the block of marble before I start my work. It’s already there, I just have to chisel away the superfluous material.”
But why can’t David be the one being chiseled away?

Carrara marble: if the surface of David were removed, it would be discovered that the inside of his head is a stone. Since Carrara marble is associated with David, it is more expensive than marble from other countries of origin of the same quality.

The Carrara River: Carrara marble is found in abundance along the Carrara River.
However, it has a different name at this point: river rock.