On Fri, Jan 29, 2021 at 7:42 PM Bruce Kellett <[email protected]> wrote:
> *There is no requirement for an infinite number of degrees of freedom.* > In physics there will never be a theory that requires infinite degrees of freedom, at least not until somebody performs an experiment with infinite accuracy, and I'm not holding my breath for that. > *Escape of just one IR photon to outer space is sufficient to destroy > reversibility.* > Sometimes, usually in fact, but not always. Not if 2 quite different events can produce the same identical photon that escapes into infinite space, and not if the photon is not even allowed to escape but Is absorbed by a photographic plate or a brick wall. A good example of this sort of thing would be the quantum eraser experiment, or the delayed choice experiment. Or just study how a Mach–Zehnder interferometer works. These experiments are possible but they're not easy because the experimenter must make sure that there's a difference between the two worlds but the difference must be very small so a practical way can be found to make the two worlds identical again so they can be nudged back together again into one world. *> The definition of 'world' in the context of QM is made exact precisely > because of this irreversibility.* > Only in pure mathematics are definitions precise, in science and and everything else they're just an approximation, a label for an idea learned through examples, a collection of words that are defined by other words. And Hugh Everett invented the theory but he didn't invent the phrase "Many Worlds", that was done by others and only gives a very approximate idea of what the theory is about. According to Everett the debate on if matter is made of particles or waves is over, it's made of waves. And in that theory the approximate definition of the world "world" is a collection of different waves that include at least one conscious being that is approximately the same in all of them. *> Worlds are well-defined * > Words are defined by other words and those words are in turn defined by yet more words. Even the word "defined" is defined by words. But whatever physical reality turns out to be at its most fundamental level I think we can be pretty sure it's not made of words. John K Clark See my new list at Extropolis <https://groups.google.com/g/extropolis> -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAJPayv0PC2xCLVb-TqzR2nHYoLzfzNekmRVht8RNqi_UGyWw8w%40mail.gmail.com.
