Why do we all see the same world?
We see the same world because what we share is the part that survives switching from one observer's view to another's, and that part is the world. Alice sees an oak table under the kitchen light. Bob finds its corner by hand in the dark. Light on her eyes and pressure on his palm share no physics, yet the two of them agree at once. What comes through both channels is relations: the edge runs 112 centimeters, turns through a right angle and stays rigid. Brown belongs to Alice's eyes, and the waxy feel to Bob's palm. A quantity that survives a change of viewpoint is called an invariant, and the shared world is made of invariants. Whatever changes from one observer to the next was never a fact about the world.
Also in Chapter 4: Why Do Two Descriptions Ever Agree?.
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 chapter 5: Why Do You and I See the Same Table?watch a universe make its own particles