FOM: good news: serious physicists believe that intuitionistic logic is important for physics

Robert Tragesser rtragesser at
Fri Oct 5 20:44:44 EDT 2001

Vladik Kreinovich wrote:

>For those who like intuitionistic logic and related research, you may want 
>read a new popular book by Lee Smolin, one of the world leading specialists 
>quantum gravity (i.e., quantization of space-time), called "Three rodas to
>Quantum Gravity".
>He strongly believes that this logic - and a more general topos approach - 
>of great physical importance to quantum gravity.
>Not only he believes in it, he cites papers by himself and other physicists
>where these logical ideas have been transformed into working physical 
   Could you elaborate?  Do the ideas have to do with peculiar models for 
phenomena intuitionistic logic/set theory supports through cunningly chosen 
of choice sequences? - From Brouwer's so-to-say uncuttable continua to 
continua composed
of somewhat more granular parts which can be pulled apart like taffy, even 
to the point
of snapping/breaking, but are not sharply separable -- a Russian 
differentiable geometer
Rachevskii had, if I recall correctly, already proposed latter models of 
continua for
modelling quantum phenomena, with the idea of building just the right sort 
systematic continuous/discrete ambiguity into the underlying 

rtragesser at

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