I don't think simulation theory is 'garbage.' It's a reasonable thought experiment. It doesn't mean it's true, or even likely. There is some modest evidence for it, especially if you like what Doctor Sylvester James Gate wrote : 'the deepest levels of reality seem to resemble code, specifically data error correcting code similar to internet browser codes.' Paraphrasing, so I could have just misunderstood that. I am sure the holographic universe folks are legitimate scientist that might find favor with it. I don't see how it earned a 'garbage' badge. It's just an idea. Something to think about.

As for "Put another way, I don’t care how hard you or a computer “thinks”, you would never be able to spin off multiple consciousnesses interacting with each other within your own head." I think a strong argument can be made for multiple personality disorder meeting this criteria. There is solid, fMRI studies that show the physical body changes with changes in personality, not just brain waves.

If we accept multiple personality disorder fits, then the group of people creating 'tulpas' have demonstrated it is possible to create a secondary personality that fits this bill. If you're curious, check out tulpa.info. Most of those successful at this, and I am one, experience the other consciousness as an entity that has autonomy. We suspect sentience. (It's hard to prove that. I suspect we frequently doubt sentience and the right to sovereignty in other fellow humans.) The Tibetan monks who invented the tulpamancy techniques believe it's all consciousness. Contrast that with the neuroscientist that believe consciousness is an illusion, in which case the above argument would be rendered mute, because a super computer could generate all the NPCs it wants to satisfy it's basic programing. In that case, nothing was violated.

But nice article. What kind of telescope you running? I am looking to invest in one for my son, and have been away from my armchair astronomy for a while.