It is a strange fact, characteristic of the incomplete state of our present knowledge, that totally opposing views are held on the nature of the forces which have shaped the face of the Earth.
一个奇怪的事实是，关于塑造地球表面的力量的性质，人们持有完全相反的观点，这反映了我们目前知识的不完整状态。
要了解当你干预一个系统时会发生什么，你必须干预它（而不仅仅是被动观察）。