🚀 go-pugleaf

In article <1992Oct6.023601.20017@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
McInnes writes:
>>ON THE OTHER HAND I am extremely sceptical of statements such as "at
>>sufficiently small length [huh? what's that?] scales, spacetime is
>>replaced by [wormholes, worms, knots ,loops, strings, etc]. Spacetime is
>>the set of all events. What does it mean to say that events are
>>"replaced" by anything? : 
>
>What's getting replaced is not events but the notion that they are in 
>one might replace this notion WITH, but it's definitely worth keeping in
>
>mind as a possibility.  It would have to be some structure which is good
>at looking like a manifold at larger distance scales.  

Huh?  I HATE using emacs and telnet together.  It sucks.  Try again:

What's getting replaced is not events but the notion that they are in
in one-to-one correspondence with points on a 4-manifold.  It's not
clear what one might replace this notion WITH, but it's definitely worth
keeping in mind as a possibility.  It would have to be some structure which is
good at looking like a manifold at larger distance scales.

Let me add in response to Hartmut Frommert's advocacy of modifications
of GR... it is certainly worth studying these and people have.  No
matter what one does along these lines one will probably want to
quantize the theory eventually, and quantizing old-fashioned Einstein
gravity will probably be good practice.  (Unless these other theories
turn out to be significantly EASIER to quantize.  Occaisionally one
hears this claim but not for torsionful or nonmetric connection
theories.)  

I certainly think it's silly to flounder around trying to replace the
spacetime manifold with strings, worms, sealing-wax, or what-have-you.
The loops, I must emphasize, simply fall out from trying to combine
general relativity and quantum theory without any deliberate quest for
the exotic.  Now the loops start out living in plain-old 3-dimensional
space, a state in quantum gravity simply being a link invariant.  But as
one pursues the mathematics one sees it might be profitable to instead
treat these link invariants purely algebraically, in which case 3-space
gets replaced by something I call the "abstract holonomy algebra".  I am
starting to write up a paper on this.  It's way too
early to take the physical/philosophical implications of this very
seriously; it's all very preliminary and I don't go around saying "The
spacetime manifold MUST DIE!!"