Wei Dai Wrote: >On Thu, Jun 27, 2002 at 03:59:49PM +0200, Bruno Marchal wrote: >> Now, and we have discussed this before, I have no understanding of the >> expression "being inside a universe". > >Being inside a universe to me means having a causal relationship with the >universe, in other words being able to affect it through decisions and >actions. That leads to the question of what causal relationships are and >how do you formalize them.
OK but from the way I tackle the mind body problem I just cannot take an expression like "the universe" as granted. Nor can I attach an observer to a unique computational history. (cf UDA) In some sense I argued that with the comp hypothesis in the cognitive science "I" belong to a sheaf of computational histories (all those histories I cannot distinguish) and "my" future is determined by proportion of the relatively consistent extension of those computational histories. (The main problem will be to explain why apparently those extensions can interfere destructively). Note that this is not unlike the consistent histories everett-like formulation of quantum mechanics. But it is crucial to understand that I cannot suppose quantum mechanics: my main result being that "IF we are machine (Turing emulable) then the laws of physics (including existence of a universe, or a multiverse, or a multi-multiverse, ...) emerges from the existence of the many relatively consistent extensions). This is not a critics of your causality/action view of being inside a universe. Just that with comp it remains to define what is a universe, or an appearance of a universe, or multiverse etc. Remember that I remain open to the idea that eventually comp will be refuted, in which case we can freely postulate the existence of a universe. Before this has been done I will stick to comp as a working hypothesis. Bruno -- http://iridia.ulb.ac.be/~marchal/
