What it means to put it mathematically is that, if you're concerned about a society today, you should be looking not at the value of the mathematical function -- the wealth itself -- but you should be looking at the first derivative and the second derivatives of the function. That's one general theme. A second general theme is that there are many, often subtle environmental factors that make some societies more fragile than others. Many of those factors
这个现象用数学思维可以这样理解：如果你要考虑一个当今的社会， 你最该关心的并不应该是这个数学函数的值， 具体而言，即一个社会的GDP；你应该留意的， 应该是这个函数的一阶导以及二阶导。 以上便是得到的崩溃社会的共性之一。其二， 总是会有许多微妙的环境因素使得 一些社会较之其他更为脆弱，而这些环境因素