problems are and what we should be doing about it and precise the knowledge is, i want to talk about charles mann. you talked about tendency and sub cultures, lineage that is go far beyond the two individuals, could you tell us a little bit more about the two tend -- tendency. i was curious where you think they come from since they're not about two individuals. >> they fundamentally come from values, one of the things that i concluded from is that many environmental disputes, you know, they sort, we discuss them as they are sort of factual as what we are really arguing about is a factual matter, you know, is climate change occurring or, in fact, what they are really fight for our values and people self-perceptions and so it's very typical for what people i call wizards, what they imagine is basically everybody, they see working on the farm, you should liberate people from drug-free and everybody should live in the city where they could have maximum independence and liberty and maximize human potential and we should all go to college and do this. and trade is, you know, and travel and globalizatio