  We propose a reformulation of quantum mechanics in which the distinction
between definite and indefinite becomes the fundamental primitive.
  Inspired by suggestions of Heisenberg, Schrodinger and Dyson that the past
can't be described in terms of wavefunctions and operators, so that the
uncertainty principle does not apply to past events, we propose that the
distinction between past, present and future is derivative of the fundamental
distinction between indefinite and definite. %The same is the case for the
quantum world versus classical world distinction of the Copenhagen
interpretation.
  We then outline a novel form of presentism based on a phenomonology of
events, where an event is defined as an instance of transition between
indefinite and definite. Neither the past nor the future fully exist, but for
different reasons. We finally suggest reformulating physics in terms of a new
class of time coordinates in which the present time of a future event measures
a countdown to the present moment in which that event will happen.
