On 06-06-2020 12:57, Bruno Marchal wrote:
On 5 Jun 2020, at 19:11, smitra <smi...@zonnet.nl> wrote:On 05-06-2020 18:07, Jason Resch wrote:On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett <bhkellet...@gmail.com> wrote:On Fri, Jun 5, 2020 at 7:16 PM Jason Resch <jasonre...@gmail.com> wrote: On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett <bhkellet...@gmail.com> wrote: On Tue, Jun 2, 2020 at 9:59 AM Jason Resch <jasonre...@gmail.com> wrote: On Monday, June 1, 2020, Bruce Kellett <bhkellet...@gmail.com> wrote: On Tue, Jun 2, 2020 at 5:39 AM Jason Resch <jasonre...@gmail.com> wrote: On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson <agrayson2...@gmail.com> wrote: On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote: I recently wrote an article on the size of the universe and the scope of reality: https://alwaysasking.com/how-big-is-the-universe/ It's first of what I hope will be a series of articles which are largely inspired by some of the conversations I've enjoyed here. It covers many topics including the historic discoveries, the big bang, inflation, string theory, and mathematical realism. Jason I see you agree with the MUH that there are infinite, identical repeats of any universe.To be clear, the MUH is separate theory from the idea of a spatially infinite universe (which is just the standard cosmological model that working cosmologists assume today, that the universe is infinite, homogeneous, and seeded by random quantum fluctuations occurring at all scales during the expansion of the universe). Define what you mean by "quantum fluctuations". There are no such things in standard quantum mechanics. Variations in the decay of the inflaton field that seeded thevariations in density that led to stars and galaxies, and confirmed byobservations by COBE and Planck. That is not how inflation models work. Are you sure about that? If so could you explain the error in this or in my understanding of it: https://www.youtube.com/watch?v=chsLw2siRW0&t=6m43s You video gives an oversimplified comic-book version of inflation. If you want to understand inflation, you have to go to a professional, expert review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys. 78:537-589 (2006). (Also in arXiv:0507632). You will see from this that density perturbations are just Guassian random fields, put in byhand, with parameters adjusted to fit the data. There are no intrinsic"quantum fluctuations". According to the theory what is the source of this gaussian randomnesses? What makes a field random if not quantum mechanics? JasonThere obviously do exist quantum fluctuations. A down to Earth example is Johnson noise. Connect a sensitive voltmeter to a resistor and you'll detect fluctuations in the voltage. The average voltage is zero, but there are fluctuations due to thermal motion of the electrons. If you cool down the resistor these fluctuations will become smaller, but even at absolute zero there will still be fluctuations in the voltage. These fluctuations at zero temperature are what we call "quantum fluctuations" in physics. Now I remember an old discussion with Bruce on this list about this, and insisted that what I called quantum fluctuations are actually "thermal fluctuations at 0 K". But at 0 K the system is in the ground state, so it doesn't matter what you name you give to the fluctuations, these are purely quantum mechanical in nature, they don't arise from an initial randomness in the initial state.Eventually, they do arise from the fact that no universal machine can know in which history she belongs, and that even the physical void is a phenomenological product of infinitely many computations. Actually, when we assume Mechanism.
It seems plausible to me that one should be able to derive quantum mechanics from such ideas involving some form of a mathematical multiverse. The multiverse aspect of the MWI is likely correct but it's problematic when considering the detailed physics. It's similar to how Einstein got the idea that gravity must be linked to curved space-time long before he had discovered the precise mathematical formulation of general relativity. Had he or someone else stuck to just vague ideas then critics would have thrashed the whole idea of curved space-time, and they would worked with retarded gravitational
potentials analogous to those used in electromagnetism.Michio Kaku has said that if Einstein had not developed general relativity that physicists would have used such a wrong relativistic formalism to describe gravity, general relativity would not have been developed before the 1970s.
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