yes that basically soil will get saturated you'll get flood. So that means you need some conditions. So here rain is a necessary condition but it's not a sufficient condition. The problem of this type of analysis really came if you go back now where is this idea of necessary and sufficient cane. So I did dig basically deeper into this. It came from geometry. In geometry it is very precise because I need to have four sides to have a rectangle and with 90 degree angle. I need to have three sides to have a triangle. There is no way around it. So I can explicitly say what are the necessary and sufficient conditions for something to be considered a triangle. That is not the case. For many physical systems, more importantly many coupled systems like where you have natural systems and human systems like our transboundary water problem. Where you have natural systems so water is getting coupled with the human systems of managing it and governing it. When they're coupled, the systems become complex. This notion of necessary and sufficient conditions are not good enough. So I'll stop here just to give you pause, see what you think about this distinction between necessary sufficient conditions, then we'll go into enabling conditions. I presume we don't have to wait 5,000 years to make judgments about such things. And I'm interested in how you think we know enough to say, that's only correlation, that's not causation. And is it really