In these institutions, one of the critical variables is the number of functional units. Many simple common property systems involve on the order of one hundred users. Conceptually, it is not surprising that we find such self-organizing capabilities in human systems, similar to those in ecosystems, because human systems are subsystems of ecosystems. But in practical terms, the adaptation of common property institutions for the solution of regional and international resource management problems is going to be challenging indeed. There exists a fundamental interrelation between natural capital, human-made capital, and cultural capital.
Natural capital is the basis, the precondition, for cultural capital.
Human-made capital is generated by an interaction between natural and cultural capital. Cultural capital will decide how we will use natural capital to 'create' human-made capital. Technologies that we develop are not simply tools we can put to good or bad use - they reflect our cultural values. Costanza et al. A necessary condition for sustainability is that processes and functions of natural capital are supported, rather than disrupted, by feedbacks from society.