  Yorck claims that the three psychological “functions” or comportments circumscribe the fixed and unalterable “natural ground” [Naturboden], or the parameters within which all human history is played out (ST, p. 26). There is no history without such fixed reference points. The economy of the three functions is not fixed (unlike the functions as such), but is always open to the play of shifting configurations and imbalances (ST, p. 24 &amp; 54). More specifically, the three functions are neither reducible to each other nor derivable from another source, making them in effect equiprimordial. However, they stand in a variable and inverse relationship to each other, where the relative preponderance of one function is offset by the relative subordination of the remaining ones, but at no time can any particular function be cancelled out altogether (ST, p. 98). This inverse relationship, coupled with the internal polarity within each function, accounts for “the restlessness of primary life” (ST, p. 32). Since life does not exist in some generality, but only as a particular configuration or alignment of its functions, the overall “totality” of the shape of a particular life is always determined by a pre-dominant position of one of its functions (ST, p. 55). This lopsidedness, which necessarily fails to express life in its “entire  fullness”[10]  (ST, p. 54), results in the instability of each particular shape of consciousness. Each real configuration of consciousness and its particular bias to one function, as well as one of the antithetical poles within, lends itself to a new correction, a new stance of consciousness, which, in turn is only a particular form, biased to a particular function, and so on. As “historical life” is nothing other than “primary life” writ large, Yorck holds that this inbuilt instability and restlessness in primary life also constitutes the “engine of history” (ST, 33). (See Section 3.2 below.)