On 2/2/2012 2:35 AM, meekerdb wrote:
On 2/1/2012 11:03 PM, Stephen P. King wrote:
On 2/2/2012 1:46 AM, meekerdb wrote:
On 2/1/2012 9:46 PM, Stephen P. King wrote:
On 2/2/2012 12:32 AM, meekerdb wrote:
On 2/1/2012 8:34 PM, Stephen P. King wrote:
On 2/1/2012 8:08 PM, meekerdb wrote:
On 2/1/2012 12:35 PM, Stephen P. King wrote:
On 2/1/2012 10:57 AM, Jason Resch wrote:



On Tue, Jan 31, 2012 at 10:47 PM, meekerdb <meeke...@verizon.net <mailto:meeke...@verizon.net>> wrote:

    On 1/31/2012 8:43 PM, Jason Resch wrote:
    Regarding the "philosopher's nothing":

    This present moment exists, and it has no cause since our
    universe is a four dimensional structure (time is a
    subjective phenomenon).  This timeless existence of this
    moment establishes that "nothingness" cannot exist.  In
    short: It is an impossible state.  The question then
    becomes: "Why should this present moment exist, and what
    else might also exist?"  So far, the answer suggested by
    our latest discoveries and reasoning suggests: a lot.

    Jason

    Or to paraphrase Quine: What is there? Everything. So what
    isn't there? Nothing.

    Brent


I don't quite agree with that paraphrasing. My point was that there is no such thing as a philosopher's nothing, not that everything exists. Such a leap would require the additional assumption that "Nothingness" is only thing that does not exist. All I said was that "nothingness" is an impossible state. This is the conclusion of accepting a four-dimensional/atemporal existence, as suggested by relativity.

Jason

Hi Jason and Brent,

I hope that you both realize that the "four dimensional structure" does not take QM into account as SR assumes that observables all commute and there is no Plank's constant. Why this is not more widely understood is mysterious to me! It is as if a simple error keeps being repeated over and over and no one has the temerity to point it out and offer a correction. Maybe people want the idea to be true so they ignore the inconvenient facts.

Onward!

Stephen

I'm not sure what your point is. QFT is done the "four dimensional structure". Or are you complaining that we haven't considered the yet-to-be-discovered quantum theory of gravity/spacetime?

Brent
--
Hi Brent,

Take a look at exactly what is going on in QFT. Yes, a *flat* Minkowskian 3,1 space-time is used for the base space of the fiber-bundle structure that is used in the QFT calculations, but this is a small hypervolume. The QFT_does not work_ when it is extended to large areas or situations where curvature is involved.


That's going to come as a shock to Robert Wald, author of "Quantum Field Theory in Curved Spacetime and Black Hole Thermodynamics"

http://www.amazon.com/Quantum-Spacetime-Thermodynamics-Chicago-Lectures/dp/0226870278/ref=sr_1_5?ie=UTF8&qid=1328160695&sr=8-5

wherein he derives Hawking radiation due to spacetime curvature and Unruh radiation from the existence of a horizon.

Brent
Hi Brent,

Hey, I am fallible, I was getting my information from Sunny Auyang's book "How is Quantum Field Theory Possible? <http://www.amazon.com/How-Quantum-Field-Theory-Possible/dp/0195093453/ref=sr_1_1?s=books&ie=UTF8&qid=1328161383&sr=1-1>", but let me ask you a question. In the derivation of Hawking Radiation, is it assumed that virtual particles "feel" gravity?

According to Wald particles are just solutions of the field equations in flat spacetime and can only be considered approximations in curved spacetime. So I'm not sure how to answer your question. His analysis of Hawking radiation is built on his analysis of Unruh radiation which depends on transformations of the vacuum state to an accelerated frame. I'm not competent to explain it - but Wald is quite readable ($7.10 used).

Brent

Hi Brent,

I will add the book to my wish list. Thanks for the recommendation. :-) I ask the question about Hawking radiation because there is a big problem with the idea that virtual particles can "feel" gravity... It creates a cosmological constant that literally explodes to a value about 10^120 greater than what we actually observe, so I worry a bit about how Hawking radiation is considered.

There's an interesting solution due to Phil Mannheim based on a conformal invariant model: arXiv:1005.5108v4 [hep-th]

Brent
Hi Brent,

    Very interesting!!!! Thanks!

Onward!

Stephen



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