>I was with friends today and they asked me a question that stumped me.
>Perhaps extropians can help: How do we *know* we are not *currently*
>uploaded simulations, running on some unimaginably advanced supercomputer?
>Is there any way to know?
The Matrix! We do not know and I suggest that it doesn't really matter. The universe we live in is, ipso facto, the universe we live in - empirical or virtual. How do I know that the universe exists at all and isn't an illusion that you all appear in? The fact is I don't. We have certain data that we choose to think of as empirical because the alternative is confined to the too hard basket - for now. Building an SI in our universe will have the same impact on our existence either way, because the SI will exist in our universe. Unless, of course, your friends are on to something and the SI that we exist within prevents our progress... Help me Neo!