Science In A Simulation

Fantastic Planet links to this article suggesting that we may all be living in a simulation being run by computers of the future with infinite computing ability. Prof. David Deutsche is concerned about what that prospect means for science:

From the point of view of science it's a catastrophic idea, the purpose of science is to understand reality. If we're living in a virtual reality we are forever barred from understanding nature.

I think Deutsche is making a mistake in assuming that the only worthy task for science is to understand the deep nature of the "real reality" in which the computer is simulating us. But I think we need to ask why science is concerned with understanding reality. I think the answer is because we have to interact with reality -- quarks and rocks and plants affect our lives in some fashion. If we're in a simulator, then the "virtual" reality around us is as real as anything can be for us. It's what affects our lives. So as long as the outside reality of the computer's world doesn't affect us, it's irrelevant. And if it does affect us, then the barrier has opened a bit and we have an opportunity to learn about it.