If God created the rock and observed the rock as God created the rock, problem solved. If there is a God, then God makes the rules, perhaps. But if there is no god, then a rock may not be defined until it is defined and described to be a rock or to be whatever. According to natural law, you would have to assume that the rock is whatever the rock is even without the rock being observed. If a rock or a tree falls in the forest, it makes a sound because sound is vibration. When a deaf person fails to hear it, the deaf still feels the vibration from the fall.
RE: MAGNUM MYSTERIUM