Unitarity, Locality and Spacetime Geometry: Foundations that Are Not Foundations

Abstract

This essay discusses a possible route towards the removal or deformation of existing physical postulates. This is looked at in light of history. The foundations of interest are unitarity and locality. How thes principles are changed or abandoned is first examined in light of previous changes in the understanding of physical foundations. These foundations are examined to question their firmness, and if they give way then unto what do they submit to as emergent properties. Suggested approaches are then proposed within light of the AdS/CFT correspondence, nonlocal BCFW amplitudes in QCD, cosmological quantum phase structure and ultimately the replacement of unitarity by deeper principles of modularity.