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Re: QM and GR.

From Odd Bodkin <bodkinodd@gmail.com>
Newsgroups sci.physics.relativity
Subject Re: QM and GR.
Date 2016-07-11 13:42 -0500
Organization Aioe.org NNTP Server
Message-ID <nm0pai$qkg$1@gioia.aioe.org> (permalink)
References <e774f48f-83e5-4a00-bb28-5fe21626b4b3@googlegroups.com> <dvednQ_V3vIC9B_KnZ2dnUU7_8zNnZ2d@giganews.com> <31cd6ad9-5e53-417f-80ca-bef6f9b0d1a2@googlegroups.com> <fb77ad17-0e85-467f-a92e-89ca7a9217ce@googlegroups.com>

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On 7/11/2016 10:08 AM, Y wrote:
> On Tuesday, July 12, 2016 at 1:00:37 AM UTC+10, Y wrote:
>> On Monday, July 11, 2016 at 1:28:38 AM UTC+10, tjrob137 wrote:
>>> On 7/9/16 7/9/16   10:20 AM, Y wrote:
>>>> I really don't see the point in these theories being combined into one. Can
>>>> anyone explain very simply the point of doing so ?
>>>
>>> Sure: the world works (i.e. in every regime that occurs in the world, at every
>>> scale, nature behaves in some manner).
>>>
>>> At present we don't have a theory that describes how nature works at every scale
>>> -- QM describes how nature works at small scales, and GR describes how nature
>>> works at large scales, but in between they are incompatible. As nature works at
>>> these intermediate scales, there must be some theory that describes it;
>>> presumably it is some sort of "combination" of QM and GR, but that is just a
>>> guess, as it could be something else altogether (and the current major research
>>> efforts are indeed something else: string theory and loop quantum gravity).
>>>
>>>
>>> Tom Roberts
>>
>> I still don't really get the point. As far as I can tell, any quantum field theory could only
>> really be used to explain particles and their 'local' interactions with some probability density
>> describing non-local interactions.
>>
>> Looking at something like GR, which seems to describe an emergent decoherence of large numbers
>> of these interactions, what we seem to have is two very different types of theory, (one which
>> attempts to explain fundamental particle interactions at the small scale, and the other which
>> approximates these to a much broader context).
>>
>> Take a biological analogy for example. Where a QFT would be describing say a number of individual
>> organisms, and their interactions, GR describes the environmental conditions for which the behavior
>> of the parts emerge en mass.
>>
>> I just don't see the need or a purpose here for a multitool, other than say clerical convenience.
>> Such clerical convenience seems to be what string theory attempts, or LQG, the outcomes of which
>> do not seem to be satisfactory theories in any scientific sense, but things that maybe useful in
>> some 'clerical' framework in order to organise all other frameworks. It's no wonder therefore that
>> either of these attempts do not provide any unique predictions.
>>
>> -y

Well, in a way you're right. Quantum field theory describes things at a 
particle level and in the domain where Planck's constant is not 
negligible, and general relativity describes things at a more macro 
level with large objects and mass interactions.

However, there is also a strong desire on the part of physicists to find 
*more fundamental* explanations. As an example of this, you can do an 
enormous amount with thermodynamics of gases without ever even 
acknowledging the molecular nature of gases. But it was of tremendous 
value to show how the kinetic theory of thermodynamics explains at a 
deeper level what pressure is due to, what entropy means in terms of 
microstates, and so on. In this sense, though you don't have to use 
kinetic theory to make a good number of useful predictions, it is 
understood by scientists that the kinetic theory is more fundamental.

In the same way, there are macroscopic laws of electrodynamics. And 
what's fascinating is that you can show where all those collective 
behaviors come from, by referring to the microscopic QFT called quantum 
electrodynamics. That is, there is nothing in the macroscopic, 
collective theory of electromagnetism that isn't accounted for in QED. 
While this is true in principle and demonstrable, this doesn't mean that 
all electromagnetic analyses are done with QED. On the contrary, in many 
cases it's useful to use the "continuum approximation" or "bulk behavior 
approximation" to do those calculations, and then you're using a non-QFT 
approach even if the underlying reality is quantum.

There's an identical program being pursued for gravity, to find the 
underlying quantum mechanical theory that, at large scales, reduces to 
general relativity in approximation.

>
> In addition (of course) in order to achieve that clerical convenience, authors of these theories have
> made bizarre ontological claims - like the existence of 1 dimensional strings etc or dark energy. It
> just seems history repeating. I imagine eventually someone like Einstein will come along and say "we
> don't need to think of these strings as existing in any form, or for Dark energy to exist in any form -
> it is sufficient to simply say that the theory makes accurate predictions combining those made by QFT
> and GR into the one clerical convenience).
>
> -y
>
>


-- 
Odd Bodkin --- maker of fine toys, tools, tables

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Thread

QM and GR. Y <yanarchi@hotmail.com> - 2016-07-09 08:20 -0700
  Re: QM and GR. Poutnik <poutnik4nntp@gmail.com> - 2016-07-09 18:02 +0200
    Re: QM and GR. "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-07-09 16:51 -0700
      Re: QM and GR. "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-07-09 17:55 -0700
  Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-10 07:16 +0200
    Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-11 06:04 +0200
  Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-10 08:25 -0500
  Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-10 10:28 -0500
    Re: QM and GR. Y <yanarchi@hotmail.com> - 2016-07-11 08:00 -0700
      Re: QM and GR. Poutnik <poutnik4nntp@gmail.com> - 2016-07-11 17:08 +0200
        Re: QM and GR. Y <yanarchi@hotmail.com> - 2016-07-11 08:12 -0700
      Re: QM and GR. Y <yanarchi@hotmail.com> - 2016-07-11 08:08 -0700
        Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-11 13:42 -0500
          Re: QM and GR. Y <yanarchi@hotmail.com> - 2016-07-11 12:07 -0700
            Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-11 14:15 -0500
              Re: QM and GR. Y <yanarchi@hotmail.com> - 2016-07-11 12:29 -0700
          Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-14 22:48 +0200
            Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-14 16:30 -0500
              Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-15 07:03 +0200
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-15 07:37 -0500
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-15 22:56 +0200
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-16 13:02 -0500
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-16 22:17 +0200
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-16 16:47 -0500
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-18 07:09 +0200
                Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-17 10:17 -0500
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-18 06:56 +0200
    Re: QM and GR. Jack Chardy <jackc@outlool.org> - 2016-07-11 15:27 +0000
      Re: QM and GR. Sylvia Else <sylvia@not.at.this.address> - 2016-07-16 15:31 +1000
        Re: QM and GR. astrofoton@interia.pl - 2016-07-16 12:15 -0700
          Re: QM and GR. Sylvia Else <sylvia@not.at.this.address> - 2016-07-18 15:01 +1000
        Re: QM and GR. Greg Buttler <grgb@novotnysite.org> - 2016-07-22 16:09 +0000
          Re: QM and GR. Sylvia Else <sylvia@not.at.this.address> - 2016-07-25 12:21 +1000
            Re: QM and GR. Tsvetana Kasatkina <tzve@noemail.info> - 2016-07-29 20:23 +0000
        Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-22 22:39 -0500
          Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-23 08:14 +0200
            Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-23 10:43 -0500
            Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-23 12:33 -0500
              Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-23 22:41 +0200
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-24 07:12 +0200
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-26 09:21 +0200
              Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-27 07:11 +0200
          Re: QM and GR. astrofoton@interia.pl - 2016-07-23 11:21 -0700
            Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-24 22:39 -0500
              Re: QM and GR. Maciej Woźniak <mlwozniak@wp.pl> - 2016-07-25 09:12 +0200
                Re: QM and GR. paparios <paparios@gmail.com> - 2016-07-25 07:02 -0700
                Re: QM and GR. Maciej Woźniak <mlwozniak@wp.pl> - 2016-07-25 16:23 +0200
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-07-25 12:44 -0700
              Re: QM and GR. astrofoton@interia.pl - 2016-07-25 10:22 -0700
                Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-27 12:15 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-29 13:51 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-29 16:04 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-31 11:32 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-31 14:19 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-31 12:35 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-31 14:56 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-31 13:37 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-31 16:09 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-31 15:03 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-31 17:11 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-31 16:05 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-01 08:17 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-08-01 12:30 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-01 15:11 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-08-01 13:36 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-01 17:02 -0500
                Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-30 08:27 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-07-31 12:25 -0700
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-08-01 13:47 -0700
                Re: QM and GR. astrofoton@interia.pl - 2016-08-01 14:17 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-01 17:04 -0500
                Re: QM and GR. astrofoton@interia.pl - 2016-08-01 18:01 -0700
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-08-01 19:57 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-05 07:04 -0500
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-08-06 12:37 -0700
                Re: QM and GR. astrofoton@interia.pl - 2016-08-05 08:37 -0700
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-08-06 12:40 -0700
                Re: QM and GR. astrofoton@interia.pl - 2016-08-06 14:47 -0700
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-08-08 13:16 -0700
                Re: QM and GR. astrofoton@interia.pl - 2016-08-08 13:25 -0700
                Re: QM and GR. JanPB <filmart@gmail.com> - 2016-08-08 14:16 -0700
                Re: QM and GR. astrofoton@interia.pl - 2016-08-10 10:52 -0700
          Re: QM and GR. Sylvia Else <sylvia@not.at.this.address> - 2016-07-25 16:45 +1000
            Re: QM and GR. Sylvia Else <sylvia@not.at.this.address> - 2016-07-25 16:46 +1000
            Re: QM and GR. Poutnik <poutnik4nntp@gmail.com> - 2016-07-25 11:08 +0200
            Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-25 12:28 -0500
              Re: QM and GR. astrofoton@interia.pl - 2016-07-25 10:51 -0700
              Re: QM and GR. wugi <brol@brol.be> - 2016-07-26 12:11 +0200
                Re: QM and GR. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-07-27 12:11 -0500
                Re: QM and GR. Thomas Heger <ttt_heg@web.de> - 2016-07-29 10:20 +0200
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-07-29 07:13 -0500
                Re: The rate at which the time axis grows, relative to the spatial dimensions. Adlbifhr Mjduhgfks <am@random.us> - 2016-08-07 15:36 +0000
                Re: The rate at which the time axis grows, relative to the spatial dimensions. astrofoton@interia.pl - 2016-08-07 11:16 -0700
                Re: The rate at which the time axis grows, relative to the spatial dimensions. JanPB <filmart@gmail.com> - 2016-08-08 13:21 -0700
                Re: The rate at which the time axis grows, relative to the spatial dimensions. astrofoton@interia.pl - 2016-08-08 13:36 -0700
                Re: The rate at which the time axis grows, relative to the spatial dimensions. Tom Roberts <tjroberts137@sbcglobal.net> - 2016-08-07 12:31 -0500
                Re: The rate at which the time axis grows, relative to the spatial dimensions. chrisv <chrisv@nospam.invalid> - 2016-08-08 06:57 -0500
                Re: The rate at which the time axis grows, relative to the spatial dimensions. Thomas Heger <ttt_heg@web.de> - 2016-08-08 07:18 +0200
                Re: _Nothing_ can change the future, present or past. Gary Harnagel <hitlong@yahoo.com> - 2016-08-08 10:10 -0700
                Re: _Nothing_ can change the future, present or past. The Starmaker <starmaker@ix.netcom.com> - 2016-08-08 11:02 -0700
                Re: _Nothing_ can change the future, present or past. chrisv <chrisv@nospam.invalid> - 2016-08-08 13:14 -0500
                Re: _Nothing_ can change the future, present or past. Thomas Heger <ttt_heg@web.de> - 2016-08-08 22:52 +0200
                Re: Nature decides _everything_. Thomas Heger <ttt_heg@web.de> - 2016-08-09 08:42 +0200
                Re: Nature decides _everything_. "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-08-09 07:16 -0700
                Re: Nature decides _everything_. "David (Time Lord) Fuller" <fuller.david@hotmail.com> - 2016-08-09 07:49 -0700
                Re: Nature programmed you to choose one over the other. The Starmaker <starmaker@ix.netcom.com> - 2016-08-09 12:09 -0700
                Re: Nature programmed you to choose one over the other. The Starmaker <starmaker@ix.netcom.com> - 2016-08-09 13:35 -0700
                Re: Nature programmed you to choose one over the other. Thomas Heger <ttt_heg@web.de> - 2016-08-09 23:53 +0200
                Re: Nature programmed you to choose one over the other. benj <benj@nobody.net> - 2016-08-09 18:17 -0400
                Re: _Nothing_ can change the future, present or past. chrisv <chrisv@nospam.invalid> - 2016-08-09 06:51 -0500
                Re: _Nothing_ can change the future, present or past. benj <benj@nobody.net> - 2016-08-09 17:51 -0400
              Re: QM and GR. kenseto <setoken@att.net> - 2016-08-02 06:41 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-02 23:55 -0500
                Re: QM and GR. kenseto <setoken@att.net> - 2016-08-03 05:27 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-03 07:39 -0500
                Re: QM and GR. kenseto <setoken@att.net> - 2016-08-05 05:25 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-05 08:07 -0500
                Re: QM and GR. kenseto <setoken@att.net> - 2016-08-06 07:51 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-06 15:57 -0500
                Re: QM and GR. kenseto <setoken@att.net> - 2016-08-06 14:49 -0700
                Re: QM and GR. Odd Bodkin <bodkinodd@gmail.com> - 2016-08-06 17:30 -0500
  Re: QM and GR. astrofoton@interia.pl - 2016-07-15 17:06 -0700

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