[FoRK] Eli holds forth on quantum mechanics

[Jeff Bone]

On Apr 17, 2008, at 12:24 PM, Lucas Gonze wrote:

> ?  general relativity vs quantum mechanics?  What's the opposition?

If you had to guess which one would survive largely unmodified for the  
longer period of time, which would it be?  If you had to guess which  
one provides a more general and accurate model of the phenomena of  
interest, which would it be?

The problem w/ GR is that it doesn't scale down well  (thus providing  
gainful employment for theoretical physicists for several  
generations.)  Also, by being an inherently continuous formalism it  
fails to capture the discrete / probabilistic nature of, well, nature  
in the small.  It also requires some relatively (NPI) gacky patches to  
explain e.g. accelerating expansion, and it makes a fundamental  
assumption - constancy of c over time - that looks increasingly  
shaky.  Furthermore, QM describes phenomena of a scale that we can  
come closer to measuring directly (and for which experiments are  
therefore much easier) than GR.  Finally, QM (particularly QCD) is the  
most *precise* theory we have, by a longshot, in terms of its  
predicted values.

The need for e.g. MOND and other theories of late to explain certain  
observasions shows the weaknesses inherent in GR.

Don't get me wrong;  I'm a fan of GR.  I just suspect that the  
interpretation of GR and its specific formulation is going to have to  
evolve significantly over time.  And I suspect that any TOE that  
successfully unifies the two will have a discrete, probabilistic  
flavor similar to QM and unlike GR.

jb