Is the moon there when nobody looks?
Yes, the moon is there, as definite as anything in the sky, because it is never unobserved. The physical universe is computed on a lower layer by native observers, simple record-keepers at the base of everything, so in principle the whole of it would be there with no human looking. The tide in the Bay of Fundy is a record of where the moon was, and every square meter of sunlight it turns back carries its position. Definiteness is a count of copies. Sixteen copies of a sixteen-bit fact push the odds of a forgery below one part in 10⁷⁷, and the moon is copied into its surroundings far more often than sixteen times. Humans still matter for something larger. Intelligent observers must evolve eventually, because only through them does the universe read itself into existence.
Also in Chapter 3: Why Would a Universe Need Anybody In It?.
This answer comes from OPH, Observer Patch Holography. OPH is a rigorous, consistent and complete description of the unified, self-creating computational Universe we inhabit. Its consistency is machine-checked: the fixed point at its core is constructed explicitly, and a theory with a model contains no contradiction.
To understand OPH and check every step yourself, start with the free book Reverse Engineering Reality. It builds the theory from the ground up, and the OPH Notebook answers your questions while you read.
read the free bookask the notebookor ask sage:read appendix a: Eighteen Questionswatch a universe make its own particles