  The full bulk path integral in a Lorentzian formulation of holography
includes metrics that violate boundary causality. This leads to the following
puzzle: The commutator of two field theory operators at spacelike-separated
points on the boundary must vanish. However, if these points are causally
related in a bulk metric, then the bulk calculation of the commutator will be
nonzero. It would appear that the integral over all metrics of this commutator
must vanish exactly for holography to hold. This is puzzling since it must also
be true if the commutator is multiplied by any other operator. We give a
prescription for the bulk path integral in which resolves this puzzle. In this
approach, the bulk dual of the boundary commutator is not the limit of the
naive bulk commutator.
