[mannykannot]

>And then one should question as to whether or not they want to believe with any fervor that spacetime has a physical sense.

As I read that, I felt it was a bit too strong - isn't the issue whether spacetime have an independent physical sense? I went back to the article, and I see that it starts "What is space? What is time? Do they exist independently of the things and processes in them?" As the argument starts with a manifold of events, an answer of 'no' to the third question seems reasonable to me (though I realize, from experience, that that's probably because I haven't fully grasped the argument.)

As far as I can tell, the article doesn't indicate any particular problem with the 'no' answer.

In the argument in section 10.3.3, don't you have to accept the reality of K(t) in order to see a paradox?

[tel]

Didn't read in enough detail to pick out the use of K.

My understanding is that the separation comes from an internal/external dichotomy. Internally we only have our observations as support for the metric, externally (and for a nicer mathematical construction) we need more structure including explicit construction of the manifold. This feels plausible externally, but involves some amount of arbitrary choice which is what is flexed to introduce the paradox.

To be honest, I'm not much of a physicist, but this idea shows up all over in mathematics.