A realistic expectation also demands our acceptance that one's allotted time on earth must be limited to an allowance consistent with the continuity of our species... We die so that the world may continue to live. We have been given the miracle of life because trillions and trillions of living things have prepared the way for us and then have died-in a sense, for us. We die, in turn, so that others may live. The tragedy of a single individual becomes, in the balance of natural things, the triumph of ongoing life.