From every-day experience we know what happens if we open a water tap. At first, the water jet is smooth, perfectly round and transparent; the physicist calls this laminar flow. But if we open the tap further and thereby increase the water pressure, this image changes abruptly at a certain point. The water jet forms strands and presents itself in a dynamic structure which somehow conveys the impression of being "muscular". This is the typical appearance of turbulent flow which remains unchanged for a while and, if the tap is opened even wider, changes over abruptly to other, similar structures. The beautiful regularity of the laminar jet, which almost seemed to stand still, is destroyed and disorder seems to rule. But appearances betray truth. It is precisely in turbulent flow that a higher degree of order rules. Whereas in laminar flow the movement of the individual water molecules follow a random statistical law, turbulent flow groups them together in powerful streams which, in their overall effect, permit an increase of throughflow. The frequently cited "limits to growth" are overcome by the evolution of the dynamic structure; they reappear as the widened limits of a new structure. In nature, processes often have more than one structure available for their unfolding. In our example, the increase in water pressure and throughflow leads to the instability of the laminar flow structure and the appearance of a turbulent structure, which in turn evolves through a sequence of turbulent structures. What we are calling here structure is nothing solid, composed of the same components, but a dynamic regime which puts ever new water molecules through the same strands. It is a process structure.
Erich Jantsch, The Self-Organizing Universe
