If what we do today will lessen the quality of our future lives, then we have to consider the
common good to be more important than our self interests. The idea of thinking about how
our actions will affect our future well being is part of sustainability. For example, if we set
fire to the big old trees in the Todd (or cut them down for firewood), someone will have a
fire to keep warm by and cook their food. However in the future, not only will there
eventually be no more trees to burn, we will also have an unhealthy river system.