 The details of Grush’s framework are too sophisticated to present in short compass. (For example, he introduces a host of conceptual devices to discuss the representation of external objects.) But in a nutshell, he contends that understanding temporal representation begins with understanding the emulation of the timing of sensorimotor contingencies. Successful sequential behavior (e.g., spearing a fish) depends not just on keeping track of where one is in space, but where one is in a temporal order of movements and the temporal distance between the current, prior, and subsequent movements. Executing a subsequent movement can depend on keeping track of whether a prior movement was successful and whether the current movement is matching previous expectations. Grush posits emulators—process models in the central nervous system—that anticipate, retain, and update mock sensorimotor feedback by timing their output proportionally to feedback from an actual process (Grush 2005).