when this is couple, we are calling the now couple natural human system problem, to look for optimal solution is impossible. So that's a recognition we must have because this is a recognition at least oftentimes we do not have when we are coming from a technical domain. From a technical domain we want to find an optimal solution very quickly. And optimal solutions are possible for a well-structured systems. I can find out the optimal temperature for my room. There is no problem because I can put enough basically heating and air conditioning and thermometer to get it done. But if I want to do optimal temperature for city of Boston, it cannot be done because city of Boston is open. Now things are coming back and forth from all kinds of from maybe from Connecticut or from Maine or from Canada, cold air is coming in, so I cannot make this. But on the other room I can do it because room is bounded. So basically it has boundaries, it can be insulated, it can be done. So if the system is bounded, system is well structured, system is well defined, optimal solutions are okay. But in most natural systems, they are not, in almost all coupled systems is impossible. When the natural system and human systems are coupled, then you cannot find it, then you need to be contingent and context. Then you say, fine