Mark Peaty wrote: > This is yet another delayed response; the story of my life really ... > > Jason: "By physically reversible I don't mean we as humans can undo > anything > that happens, rather physical interactions are time-invertible. If you > were shown a recording of any physical interaction on a small scale, an > elastic collision of particles, the decay of a nucleus, burning of > hydrogen, it would be impossible for you to tell if that recording were > being played in reverse or not, since it is always possible for that > interaction to occur as it does in either direction of time." > > MP: This is only true for 'individual' reactions on the micro scale, but > even then the 'truth' about the reversibility can only really be > maintained by hiding the truth about the context. For example, it is > logically possible for certain atomic nuclei to collide at just the > right velocities and fusion will occur. In reality however the > probability of what are normally fission products coming together to > make a uranium nucleus is so close to zero you are never going to see > it. [I don't know much about the physics but my casual believe is that > heavy elements are created through various long and complex 'ratchet' > accretion pathways in which nuclear isotopes of H or He enter heavier > nuclei.] Like wise the burning of hydrogen; it seems simple enough and > yes it is 'reversible', but does the reverse occur? Not where you and I > can see it. > > Jason: "Quantum mechanics makes the universe seem random and > uncomputable to > those inside it, but according to the many-worlds interpretation the > universe evolves deterministically. It is only the observers within > the quantum mechanical universe that perceive the randomness and > unpredictability, but this unpredictability doesn't exist at the higher > level where the universe is being simulated (assuming many-worlds). "
This is mixing Everett's relative state interpretation with the idea that the world is a simulation. These are not the same and maybe not even compatible. The world evolves deterministically in Hilbert space and the "many-worlds" are projections relative to us. Whether this can be simulated, except in a quantum computer, is questionable because the Hilbert space is infinite dimensional. Is some fixed finite resolution sufficient for simulation? > > MP: I don't think I can accept this. Maybe I sound arrogant in saying > this, but I think the idea of simulation is used a bit too loosely. I > know there are those lurking on the Mind & Brain list and JCS-online who > would say I am 'the pot calling the kettle black', because I am always > asserting what I call UMSITW [pronounced um-see-two for English > speakers] - updating the model of self in the world - is the basis of > consciousness. But they misunderstand me, because I do not say there is > anyone else doing simulation, merely that we experience being here > because the universe has evolved self sustaining regions within itself > which maintain their structure by means of dynamically modelling > themselves and their local region so as to avoid fatal dangers while > obtaining everything they need from their environments. My point here is > simply that the universe is its own best simulation and that any ideas > of something greater, such as a Matrix type operation, are science > fiction only. Why? Because for a feasible universe like the one we seem > to inhabit to be deterministic does not require that it is predictable > nor that it can be repeatable. Nobody knows to what extent quantum level > events are intrinsically random as opposed to being _pushed from > 'behind' or 'below'_ so to speak. > > That is one thing. Another thing is that no entity or set of entities > could know if their 'simulation' attempt was doing what they wanted in > every detail because to attempt to find this out would interfere > irreversibly with the unfolding of the world. This assumes that the simulation must be quantum mechanical - but I think that would defeat the whole point of assuming a simulation. If the world can be simulated classically, then it can be monitored without interference. Brent Meeker --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~----------~----~----~----~------~----~------~--~---
