The problem arising at the level of second-order observation within a system is to homogenize the heterogeneity of the system’s constituents. Secondorder observation may intuitively categorize these phenomena as belonging to one and the same system yet fi nds it diffi cult to defi ne the common operational denominator for all of them. Systems-theoretically speaking, second-order observation seeks to fi nd the difference schema which allows fi rst-order observation to draw its operational boundary.