***If you read the exchanges between Dick and Yanniru, you will discover that Dick has consistently and adamantly denied assuming symmetry principles. Now, did he "use" them? I don't think either of us is competent to answer that, or to understand the role symmetry plays either in Dick's work, or even in Emmy Noether's work.***
I think you are incorrect here. See, for example:
***You didn't see such a response because I don't claim that symmetries cannot create the type of physics that Dick's paper produces (which, incidentally is the same type of physics that has been produced by scientists.)***
But, there is a reasonable claim that the use of symmetries is what enables Dick to achieve his result. Dr.D loses his case since he is operating on the same assumptions as physics.
***What Dick has proved with his "fancy work" is that you don't need to make that assumption. Instead you can prove that it must necessarily be so for any communicable universe. He has removed the inescapable doubt that accompanies any assumption.***
But, if symmetry principles is an assumption as he admitted, then what differentiates his accomplishment from that of Emmy Noether?
***It isn't that Dick has discovered a new and different physics that should replace the old physics. What he has done is to find a firm and "true" foundation on which much of physics can be derived from pure thought without any appeal to experience or experiment. This forms a watershed separating out those aspects of our universe which must be the way they are from those aspects which retain some degree of freedom.***
The contention is that the foundation is simply symmetry. Dick's formulation reduces to Alex's formulation. That is, the universe is mathematical.
***If acknowledged, this could be useful for science because they could then deliberately devote their expensive experimental resources only to those parts of physical theory which are not tautological. It's a waste of time to run an expensive experiment only to prove that A = A.***
It isn't tautological to use symmetry. The key issue is how nature is symmetrical. There are many symmetrical theories, but few happen to be true. If that wasn't the case, then particle physics would be much easier to do.
Warm regards, Harv