19 The grand mediocrity of today—everyone being the same in survival and the number of offspring—means that natural selection has lost 80% of its power in upper-middle-class India compared to the tribes.

19 今天的巨大平庸——每个人的生存和后代数量都一样——意味着与部落相比， 自然选择在印度中上层阶级中失去了 80% 的力量。