[sjastro]

Chris,

Originally Posted by cwjohn

Steven

First of all "A physicist states" implies that you speak for all physicists. This is a somewhat arrogant statement. By virtue of an honours degree in physics I suppose I am theoretically a physicist albeit not a practicing one. I would not state that a photon is "created ..." but rather that a photon is "described by the Lagrangian....".

That is your assumption which is incorrect.
I’m stating the mainstream view which is supported by a vast majority of physicists who partake in research.

So you say a photon is created to preserve the conservation laws. Why? Because Noether said so in 1920.

This makes perfect sense???? Why?

It makes perfect sense particularly when looked at from a historical perspective.

Noether’s theorem is the evolution of an idea starting from around the 1830s when Newtons second law F=ma was derived by defining the gravitational field as a dynamical system using a Lagrangian.
The use of a Lagrangian did not require Newtons second law to be known beforehand.
Similarly the Lagrangian of an electromagnetic field defined as a dynamic system doesn’t require photons to be known beforehand either. A photon is a prediction of the local invariance of the Lagrangian under a U(1) or rotation transformation.
If you believe that QFT is simply describing a phenomena than how do you explain the other gauge bosons which are predicted by QFT but were not observed at the time.

Nobody argues that QFT and the math of symmetry describe the Standard Particle Theory par excellence. Many emminent physicist (for example Lee Smolin) do not accept this as a reasonable end point for our deliberations. And indeed if this were to be the case there are many very smart physicists wasting their time investigating string theory and quantum loop gravity.

Both string theory and quantum loop gravity draw heavily on QFT. Neither theory departs from the symmetry theme of QFT and both are examples of gauge theories.
The very smart physicists still work on QFT such as Ed Witten who has made significant contributions.
Why raise string and quantum loop theories in the first place?
Neither provides the "realistic" approach you are seeking.

I think this is definitely true and it is an argument that goes back to Einstein and Bohr and continues to this very day. You are content to accept mathematical descriptions as reality, and indeed you have quoted the leading proponents of this proposition (a metaphysical proposition to boot). There are others (and I fall into this camp) who do not accept this as "reality" but rather seek deeper explainations. However, to lump all physicists into your way of thinking is not reasonable.

I have to ask you the obvious question, is there any theory in physics that satisfies your criteria of providing a realistic approach?

Regards

Steven