"Theoretical physics consists of making guesses about the nature of cause."
No argument from me on that, James. I have often said that theorizing is the art of good guessing.
"No one knows what cause is including you."
I'm not bothered by that, though. Chalk it up to lack of ambition.
"The question about: Why does E=mc^2 is not answered by either of us acknowlodging that it works."
It's enough of an answer to suit me.
"There wsas a path to it, and, there may be more than one path backward from it."
Maybe. What one has to keep in mind, though, is that the path is not linear. In these forums, much is made of the speed of light constant, when actually -- from a physical point of view -- it is entirely meaningless. That E = m is sufficient; the constant only provides a rational way to measure the equivalence. The constant c is a limiting factor -- that's the reason, in fact, that "special" relativity is called by that name; the theory is limited to the special case of uniform motion. The general case of accelerated motion extends to classical gravity.
"It is important for theoretical physics to explore both the path to it and any possible paths back from it because the path to it included accepting guesses about the nature of cause."
James, I'm afraid any path one takes will include guesses about the nature of cause. I don't see any reason to torture oneself over it.
Tom
