From the standpoint of sustainability, and the relationship with environment, if we are going to consider landscapes as being inhabited as opposed to being wilderness, and removing the people from the landscape, then the culture that mediates between the people and the landscape is a very important element of sustainability in my view. At the root of culture, we find identity. So questions of identity are fundamental to understanding sustainable practices, sustainable communities, sustainability in general terms, and probably fundamental to being able to define sustainability ultimately as well.