This initial précis of the relation of psycho-statics to psycho-mechanics is helpful for understanding Herbart’s claim that “the inhibition sum [S] must, in accordance with its law, continuously fall” (SW IV: 341; cf. SW V: 338; Felsch 1904: 195; Boudewijnse, et al. 1999: 182; Weiss 1928: 83, f.). This statement, on the face of it, is deeply puzzling, and points to a vexing ambiguity in his usage of the term “inhibition sum”.  For by speaking of the “falling” (i.e., diminution) of the inhibition sum, Herbart gives the impression that it is variable. But as our discussion of the inhibition sum above showed, Herbart in psycho-statics conceives it as the sum of the (amount of) inhibition each of a number of conflicting representations must partially “bear” for them all to reach a state of equilibrium. But this sum is in fact a fixed quantum,[40] a constant, dictated by the inherent vivacity of each representation and the degree of opposition[41]  among representations. In a case examined above, S is the load actually borne by a and b when they reach equilibrium (cf. 3.3.1.1).