If you look at it in terms of physics, when a wave hits its trough it must rise up again. The cultures of East and West are the same. Do we not often say, "ten years the river goes east; ten years the river goes west"?
所以若以物理原理來看，波浪到了谷底必將翻升，東西文化亦同，我們不是常說「十年河東、十年河西」嗎？