Very, very interesting, Dan. Cosmology is always a lot of fun -- even when I don't really understand it, which is 99% of the time.
That said, there are, I think, at least a couple of problems with the exposition you have quoted.
First of all, as I (mis?)understand it, time and space were never "non-existent," in that they existed in potentia. They may have been all scrunched up in that "singularity," but they were waiting to be born, as it were. So, as far as I am concerned we are right back where we started -- that is, with the question Why?
Quantum physics is probably not the last word. What do you know about superstring theory? According to my youngest son, who dotes on this stuff, if the superstringers are proved right, a lot of quantum physics will have to be dumped. Einstein would have been happy.
Joan |