Hal wrote: >I wonder if you consider the possibility that there is no matter of fact >as to whether we are living in a simulation? Suppose that we live in real >life, and also get simulated one or more times, then our consciousness >cannot be localized to any specific instantiation.
A brain (or a particular simulation of a brain) can refer indexically to itself. Suppose you have two brains, A and B, in exactly the same internal states, both of whom think of themselves that they are in a red box. Suppose A is in a red box and B is in a blue box. Then A has a true belief and B has a false belief, and there seems to be an objective fact of the matter that this is so. When I'm considering the hypothesis that I'm in a simulation, we should think of this as: The brain that is thinking this thought is being implemented on a computer rather than in immediate physical reality. There may be other brains thinking different tokens of qualitatively identical thoughts, some of which are simulated and some of which are material, but that is beside the hypothesis that is being discussed. >Perhaps you are considering posthumans who simulate variations on possible >histories? In that case only those simulations which happen to match >the past exactly would give rise to this question, which is arguably a >small fraction of simulations assuming imperfect knowledge of the past. I think a version of your worry would pertain in this case too - one could ask whether there is a fact of the matter whether my current observer-moment is simulated or material. And the answer would be the same, that the hypothesis considered refers indexically to its token implementation. Nick Bostrom Department of Philosophy, Yale University New Haven, CT 06520 | Phone: (203) 432-1663 | Fax: (203) 432-7950 Homepage: http://www.nickbostrom.com

