John Tierney has a fun piece at the NY Times exploring the possibility that our entire existence is the product of some Matrix-like simulation your geeky great-great-great grandson is running on his bedroom computer.
But now it seems quite possible. In fact, if you accept a pretty reasonable assumption of Dr. Bostrom's, it is almost a mathematical certainty that we are living in someone else's computer simulation.
Dr. Bostrom assumes that technological advances could produce a computer with more processing power than all the brains in the world, and that advanced humans, or "posthumans," could run "ancestor simulations" of their evolutionary history by creating virtual worlds inhabited by virtual people with fully developed virtual nervous systems.
Some computer experts have projected, based on trends in processing power, that we will have such a computer by the middle of this century, but it doesn't matter for Dr. Bostrom's argument whether it takes 50 years or 5 million years. If civilization survived long enough to reach that stage, and if the posthumans were to run lots of simulations for research purposes or entertainment, then the number of virtual ancestors they created would be vastly greater than the number of real ancestors.
Let's hope our God doesn't spill Cherry Coke on the keyboard.