We do not actually perceive anything as a singular thing, only the displacement of the thing. This supersedes the notion that we are relocated to consider every instant of a system as hindsight—for this is most surely the case. Rather, any given instant in time as we perceive it is nothing more than the displacement of matter by a force, an event. This force is a thing which we are incapable of observing; we are capable of detecting effects which are the displacement of matter and artifacts as a result of their being effected by that force. If matter is stable with respect to a given durational scale (fidelity) beyond comprehension, an observer must be in a state of change in order to be made aware of the matter’s presence.
In short: observation may occur only upon the advent of difference within a given system.
An observer is never permitted to single out an actual thing, only moments before (memory) and after an event which constitute a duration. This operation could be seen as analogous to a derivative due to the instantaneous reading of any given event being governed by the behavior of a system which immediately surrounds that instant. In this regard we must perceive at the level of the derivative because we are incapable of understanding the thing as a singular; we must work through a durational event. Here, the density of matter is taken as the durational gap between each newly encountered bit of information. Thus, this durational gap is governed by the encounter of relative bodies as such an encounter implies interaction, be it an organic or inorganic observer.
As a matter of refinement (fidelity), the corresponding subdivision of a system thus becomes a function of this duration. An appropriate subdivision must be taken into consideration, however, as a level of refinement must be adequately suited to its environment and desired level of information acquisition. Given too dense of a refinement, any system will appear to be static at a particular instant.