Are You Living In a Computer Simulation? (2003)

It's worth taking into account that people tend to have two entirely separate ideas about the nature of any such simulation.

The first one is a Matrix-like universe: a world designed from the ground up to be an illusion specifically for us - a computer program so idiosyncratic as to be utterly implausible, which only cares about deceiving human minds into living in an artificial environment. This is the concept of a computer simulation always invoked by the popular media whenever this subject comes up.

The second one, which is what scientists usually mean, is an actual simulation that merely runs the basic processes of physics from which all the other things in the universe emerge - and these include accidentally, among other things and quite marginally, intelligent life forms such as humans. It's merely an uncaring physics simulation indistinguishable from a "natural" universe.

In the end both of these are scientifically barren concepts. The Matrix is an implausible just-so story with quasi-religious undertones, and it's a concept that exhibits quite a few glaring holes the closer you look at its practical implications - holes which seem like they are in disagreement with daily observation and hence should lend themselves to falsification. The cold physics simulation on the other hand, while it doesn't share the intellectual weaknesses of the Matrix, gets us rapidly to a point where we might ask what difference it makes at all whether the fabric of reality is running on an artificial or "natural" substrate if there is no hope of ever finding out.

I've always thought this part was, by far, the most likely. It would be unethical to create a simulation in which the simulated beings were sophisticated enough to be self-aware and capable of significant suffering. It's the same thing that's caused me to shift from "I don't believe in god" to "I believe there probably isn't a god". For example, infants have been raped in Africa due to the virgin cleansing myth, and every year thousands of people kill themselves due to unmanageable misery. Not to mention the way that so many people die of "natural" causes, e.g. drowning in their own phlegm only to be revived by hospital staff for another go-around.

I recall reading a science fiction story that involved the first human spaceship to reach the edge of the universe. When they tried to go through they bounced off, it was impenatrable.

Then we cut to 2 higher dimensional beings, and one says, "On that run it took life only 14.7 gigayears to reach the edge."

The other one says, "Great! Let's do another run. Sterilize the medium."

When I imagine an intelligent life form simulating the universe, it might as well be a simple creature just pushing little stones from cell to cell across a coordinate system drawn into the sand of an impossibly huge plain, using a few very simple rules about where stones move on every single cell. And when the creature gets to the last stone in the grid, it starts the same thing again from the top.

This is also not my idea, I don't remember where I heard it first. But it's appealing for several reasons. It illustrates that no intelligence is necessary to run the universe. More fundamentally, however, it shows how a higher-dimensional being might very well have no real concept of what goes on in here. ;)