# Constructing theories from duality: my response to John Wheeler

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## Recording Details

Scientific Areas:
Collection/Series:
PIRSA Number:
13100072

## Abstract

The
late physicist John Wheeler, was renowned for his Socratic method of conducting
physics discussions. "Why is general relativity the way it is? What makes
it special?" were reportedly questions one should expect in his
presence. There are different answers to these questions, each requiring a set
of assumptions - which Wheeler would likely question again - and each bringing
with it new insights into physics as a whole. This talk will put forward
new principles for deriving general relativity. Perhaps more than is the case
with other construction principles, the principles introduced are not
limited to the derivation of general relativity, requiring only an
specification of the theory's phase space in order to be applicable. To
be less enigmatic, one defines observable equivalence between physical
theories in the Dirac constraint setting, and then the principle merely
searches theory space for two equivalent (or dual)

fully constrained

theories.
We find it quite remarkable that such a complex theory as general relativity
emerges, when no initial presupposition even on the existence of space-time is
made. If there is time (and I will argue there is!) I will discuss
another issue that also distinguishes the present set of
assumptions: the possibility that they are in a concrete sense
self-selected", which I like to think would be more satisfactory to
Wheeler's line of questioning (or at least give him more to chew on).