Sorry I won't be with you this week. I find the posted comments interesting and thought provoking and I am sure the session Friday will produce even more. I'd like to offer that the only thing that sustains civilization is the process of water as it cycles throughout all living and non living systems, the process of nutrients as they cycle between living and non living systems, the process of the inter-relationships of all living systems, and the process of solar energy powering the entire thing. Therefore, the health of these processes represents our life bank account. What I mostly read in books like Friedman's is how  to differently use the interest that is spinning from these bank accounts - and in some cases - even use some of the principle from time to time. McKibben offers a little more help in that he refrains from tapping the principal to maintain a society. However, to be sustainable, I want to read suggestions as to how we can increase the principal. What must we do to increase the size of the bank account. Friedman offered nothing to me as far as this is concerned.