The Production of Time
  I suggest that measurement in quantum theory should be regarded as a sense of time (of things happening), which is as important as the conventional relativistic notion of time. A key question -- of basic physical interest whether one accepts the arguments here or not -- is, What physical criteria determine when a measurement takes place? I suggest a way in which the answer to this may be bound up with the resolution of some pathologies associated with the stress-energy operator, and may at the same time determine the cosmic flow of time. The problem of reconciling the quantum sense of time (measurement) and the conventional relativistic one gives some indication that the the correct "quantization" of gravity is essentially different from that of other fields. 
Adam Helfer