Le 29-août-06, à 13:14, Stathis Papaioannou a écrit :

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> I'm not necessarily talking about every possible computation being > implemented by > every physical system, just (at least) the subset of finite > computations implemented by > a physical computer or brain. I think this is another way of saying > that a recording, or > a single trace of a computation branching in the multiverse, can be > conscious. To prevent > a recording being consious yoiu can insist on counterfactual > behaviour, but that seems an > ad hoc requirement introduced simply to prevent the "trivial" case of > a recording or any > physical system implementing a computation. I think Maudlin's reasoning (better than the movie graph actually) shows exactly that. What Maudlin shows is that you can have some "recording" of a computation, and thus it does not handle the counterfactuals, but which can be made handling correctly the counterfactuals by adding pieces of inert matter, having no comp-genuine physical activity at all. So the counterfactual correctness demand can be provided without adding *any* physical activity. So, for a physicalist, counterfactual should be a red herring 'even with the quantum MWI (but as Russell points out, this is slightly more difficult to show). For a computationalist, this means the entire "physical activity" is a red herring. The only counterfactuals which play a role are those corresponding to the mathematical structure of the computations. The physical emerges from the computational structure, which is entirely define by the number theoretical relation which are true independently of any physical considerations. More technical remark: Counterfactuality is a very difficult notion. It is certainly one of the philosophical notion where logic (as a field of math) can help. The best work has been done by logician like David Lewis (notably in his book "counterfactuals") and Stalnaker. Now the quantum logician Hardegree has shown that, at least formally, Quantum Logic (QL) can be seen as a logic of counterfactuals. QL gives a genuine notion of proximity among "worlds" capable of providing truth value for counterfactual statements. This shows that the movie graph or OLYMPIA can be used for providing a shortcut between comp and the quantum. Alas, the movie graph and/or Olympia thought experiment is far subtler than the UDA (at least the seven first steps), and I am not following that road. The counterfactual logic and QL necessary for a minimal notion of comp-causality is provided by the G and G* variants Bp & Dp (corresponding to the "intelligible matter" secondary hypostase in Plotinus, and Bp & Dp & p (corresponding to sensible matter) in the lobian interview. Bruno http://iridia.ulb.ac.be/~marchal/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~----------~----~----~----~------~----~------~--~---