What we see is just a simulation our minds create based on the data we receive from our sensory receptors. There is lots we cannot see. Perhaps even hidden doorways.

One of the first times I was on mushrooms I was in the bathroom looking at the wall, and it was as if there was a portal there. I was looking through and there were things looking back.

Perhaps all reality is simulated as that is just the nature of how things work. Our universe(simulation) could have other universes overlapping on top of us, but on a different frequency or wavelength so we cannot see or interact, but perhaps they can see us.

Many religious ideas are based around a spiritual world which we cannot see, and there is the idea that this world is an illusion to trick us into forgetting our real selves.