My grandfather's hammer has been in our family for sixty years. The head is iron, the metal is dark with age, and the handle is wood he cut himself. (11) My father put a new handle on it when I was small. Last year I put on the third. A friend once asked whether it is really the same hammer, (12) almost every part has been changed. I did not know what to say. (13) I think the answer is yes, and that the answer has nothing to do with the wood. A thing that is kept is not the same material year after year, (14) it is the same care, handed from one pair of hands to the next.
Turn on a light and something far away changes. (15) Most of the power in this country still begins with something being burned, and the gas that burns was made by plants that lived long before any person did. When we use it, we are spending a collection that took millions of years to build, (16) it cannot be filled again while we live. Wind and sun are different: they arrive every day whether we use them or not. (17), the question is not only what energy costs today. It is what we are borrowing from the future, (18) from whom, and we must answer it together.