  As observers of the universe we are physical systems within it. If the
universe is very large in space and/or time, the probability becomes
significant that the data on which we base predictions is replicated at other
locations in spacetime. Predictions of our future observations therefore
require an assumed probability distribution---the xerographic
distribution---for our location among the possible ones. It is the combination
of basic theory plus the xerographic distribution that can be predictive and
testable by further observations. This is illustrated by examining a toy model
of a classical deterministic universe with a fixed flat metric.
