It's an interesting thought really. Quite a few different scientific and other studies have shown that our understanding and perception of who, and what we actually are, isn't always what we expect. Using the many worlds hypothesis, there can be many more versions of 'you' in a multi-verse, so just because you think you are the definitive version, how can you possibly know for certain?
There are quite a few Horizon episodes knocking about Youtube that, in one way or another, make allusions to this.
It's a theory. And as such it is as good a theory as any other that tries to explain what our universe is doing here.
That said, it remains just a theory, like all the others, until someone from the astrophysics community actually comes up with some proof that is isn't just a theory and is scientific fact. I'm not too sure that will be any time soon. Let's just hope if it can be provable, someone does it before whoever/whatever is running the simulation gets bored and switches it off.
The best description I've heard of "THE UNIVERSE AND EVERYTHING!" is that of a guy living at the south pole in a film by Werner Herzog. He believed that our only function is to WITNESS.The modern perception of science is that it is totally free from the hindrance of things like spiritualism and religion. However, just like the myth, legend and dogmatism of religion, scientists fall for the incredible and outlandish to answer our questions as to why we are here because the same human traits are abundant in the Pope and the Nobel prize winner.An infinite number of alternative universes? Complete speculation.The good news is that all that is good in the human world has been created by humans. The "divine" is within us all.