  Analogous to G\"odel's incompleteness theorems is a theorem in physics to the
effect that the set of explanations of given evidence is uncountably infinite.
An implication of this theorem is that contact between theory and experiment
depends on activity beyond computation and measurement -- physical activity of
some agent making a guess. Standing on the need for guesswork, we develop a
representation of a symbol-handling agent that both computes and, on occasion,
receives a guess from interaction with an oracle. We show: (1) how physics
depends on such an agent to bridge a logical gap between theory and experiment;
(2) how to represent the capacity of agents to communicate numerals and other
symbols, and (3) how that communication is a foundation on which to develop
both theory and implementation of spacetime and related competing schemes for
the management of motion.
