I A question about the other observers

[PeterDonis]

What about post #21?

I didn't get the impression you were hinting at staclexchange stuff being right

Correct.

 

[PeterDonis]

we can know, in principle, the observable properties of any particularly interesting thing, even of some piece of a human brain

Yes, if you only need to know particular observable properties that are compatible with each other.

all such properties together do specify the actual spacetime universe

You can't know all such properties together. You can only know a subset of them. That subset is not sufficient to specify an entire state for the universe.

 

[JamieSalaor]

What about post #21?

I didn't get the impression you were hinting at staclexchange stuff being right

I'm going to give Hartle's work a read.
Thanks for everything!

Honestly mate don't worry about it. That stackexchange stuff was nutty...