What's in your simualtion?

I read a rather ingenious, but fallacious, twist on the "we're all living in a simulation" trope.

Imagine it's the year 10,017 of the Common Era (CE). Now suppose all that makes a human being human can be reduced to physical processes. Surely by now, in 10,017, we're fully capable of simulation a human being in their entirety. Surely we can now simulate several people and get them to interact (like the game "The Sims"). And surely we can set these human simulations to interact in a simulation of what we know thus far about the world and the universe.

Surely.

That's a large set of assumptions, but not entirely an impossible one. It may be a human brain is too chaotic to simulate entirely. There's also the fact that simulations tend to be simplified versions of reality. But let's overlook this and grant the assumptions (I know what very certain priest will object to as well; I concede it's possible).

Now on with the fallacy.

Since we'll be able to simulate universes with humans in them, at one point we'll simulate our ancestors (don't ask me why). We'll build several such simulations, of course, perhaps with different conditions, or all identical to see how they develop. And within these simulations, the simulants (or sims) will no doubt build simulations of their own (which of course we know we do all the time).

Let's call the real reality "base reality," with all others being simulated realities.

Now, given there will be a very large number of universe simulations with human sims, odds are we are in one of these and not in base reality.

Did you spot the fallacy?

But it might be a good idea for a story.

For the record, there was a story based on this in one of the many TZ incarnations. Spoilers follow:

As I recall a woman saw changes in her house, family, etc. and no one else seemed to realize it was happening. In the end she changes, too, and we cut away to a little girl. The girl's mother asks her to come to dinner if she's done upgrading her virtual family.

It wasn't the worst ep in a recent TZ incarnation (I find the pure horror ones in even the original TZ to be ho-hum).

What if you were a sim in a simulation?

There's a series of novels, the Gateway series by Frederick Pohl, where this is part of the overall plot. People can choose to have their personalities and memories preserved electronically at or near death, and then they can interact with other dead people in a simulation. They can also interact with actual living people.

The simulated people can change their appearance, circumstances, etc (RAM is cheap!) however they want. At one point a minor character commits suicide in order to "live" in the simulation. She had been dissatisfied with life, and found "life" in a simulation more appealing.

I never cared for that idea. The implication is that you can die physically but continue to live spiritually forever. The reality is you die, and a copy of you goes on.

But if you've always been a sim, things are different. The real you is a collection of bits running inside a computer.

There's a novel called Steel Beach by, I think, John Varley, with a similar idea. People can enter simulations and live in them, though that's not the main thrust of the book. At one point a character believes she has spent months or years on a simulated desert island. But it turns out she was on the simulation for only a short time. Instead memories were implanted in her of a long time spent there.

Though I didn't care much for the novel, that's an intriguing idea.

And there's the much-hyped Matrix movies. Though there was never any doubt what was real and what was simulated, and people preferred one thing over the other (I only saw the first one).