The world in which we live is a small garden of well-explored territory surrounded by a dim and dark forest of disasters. Disasters lurking in the distance are legion: asteroids and comets; world-wide pandemics and plagues; nuclear and non-nuclear wars; droughts, famines, and floods; volcanic eruptions, earthquakes, and tsunamis; human over-population and extinction of non-humans; rising temperatures and sea-levels; falling temperatures and spreading ice ages; exhaustion of clean air and water; disappearance of forests, farms, and fish.
我们所在的这个世界好比一座建立在仔细探索过的领地上的小花园，然而环绕花园四周的却是幽暗森林般无边无际的灾难。这些潜伏在不远处的灾难数量众多，不胜枚举：太空中的小行星和彗星；大规模爆发的流行病和瘟疫；核战争以及常规战争；旱灾，饥荒和洪灾；火山喷发、地震和海啸；人口过量以及众多物种的灭绝；地球温度升高时有海平面上升的灾难，地球温度下降时又害怕冰川时代不断蔓延；清新空气和水资源的枯竭；还有森林、农田和鱼类的消失。