 The earliest and best-known version of ontic pancomputationalism is due to Konrad Zuse (1970, 1982) and Edward Fredkin, whose unpublished ideas on the subject influenced a number of American physicists (e.g., Feynman 1982, Toffoli 1982, Wolfram 2002; see also Wheeler 1982, Fredkin 1990). According to some of these physicists, the universe literally is a giant cellular automaton. A cellular automaton is a lattice of discrete cells; each cell can be in one of finitely many states, and each cell updates its state in discrete steps depending on the state of its neighboring cells. For the universe to be a cellular automaton, all fundamental physical magnitudes must be discrete, i.e., they must take at most finitely many values. In addition, time and space must be fundamentally discrete or must emerge from the discrete processing of the cellular automaton. At a fundamental level, continuity is not a real feature of the world—there are no truly real-valued physical quantities. This flies in the face of most mainstream physics, but it is not an obviously false hypothesis. The hypothesis is that at a sufficiently small scale, which is currently beyond our observational and experimental reach, (apparent) continuity gives way to discreteness. Thus, all values of all fundamental variables, and all state transitions, can be fully and exactly captured by the states and state transitions of a cellular automaton.