Hal Finney wrote:
So again, is it enough to look at the natural laws of our universe in order to decide whether the consciousnesses within it are real? Or do we need more? Can we imagine a universe like ours, which follows exactly the same natural laws, but where time doesn't really exist (in some sense), where there is no actual causality? I have trouble with this idea, but I'd be interested to hear from those who think that such a distinction exists.
For me, it's not that I think it's meaningful to imagine a universe just like ours but without causality, rather it's that I think causality is probably important to deciding whether a particular system in our universe counts as a valid "instantiation" of some observer-moment, and thus contributes to the measure of that observer-moment (which in turn affects the likelihood that I will experience that observer-moment in the future). I think if you run a simulation of an observer, and record the output and write it down in a book which you then make thousands of copies of, the static description in all the books most likely would not have any effect on the measure of that observer, since these descriptions lack the necessary "causal structure". I sort of vaguely imagine all of spacetime as an enormous graph showing the causal links between primitive events, with the number of instantiations basically being the number of spots you could find a particular sub-graph representing an observer-moment embedded in the entire graph; the graphs corresponding to the physical process that we label a "book" would not have the same structure as graphs corresponding to the physical process that we label as a simulation of a particular observer. Of course, as I've discussed with you earlier, I'd also speculate that the appearance of an objective physical universe (the graph representing all of spacetime) somehow emerges from a more basic theory that assigns both absolute and conditional measures to every possible observer-moment (each represented in my visual picture by a sub-graph).