  As repeatedly emphasized by Einstein our knowledge of the structure of space
and time is based entirely on inferences from observations of physical objects
and processes. At the most fundamental level these objects and processes are
described by quantum theory. However, the ontological status of the theoretical
entities employed by quantum theory is a matter of considerable debate.
Furthermore, the nonlocal correlations identified by Bell cannot readily be
explained within the standard relativistic framework. This suggests that we
should re-examine our understanding of spacetime.
