Our conception is that of a theory about the system in an inertial state... if the organism is a system in an inertial state, as our law expresses it, the metabolic processes generally have to follow the established system; the ever progressing findings must replace the general expression of 'a system in an inertial state' by a more and more detailed knowing about the nature of this system and its chemical, osmotic, fermentive system conditions.

Bertalanffy (1929, p. 95-97) as cited in: Felix Müller, M. Leupelt (1998) Eco targets, goal functions, and orientors. p. 308