But beyond the extremes, additions or subtractions to our external circumstances make very little difference.

但在这些极端情况之外，增加或减少的外部环境,产生的区别很小。

哈佛公开课 - 幸福课课程节选

Man is born in a state of the most helpless dependence on other people."

人生来就处在一个极端无助的,依赖别人生存的环境中"

耶鲁公开课 - 美国内战与重建课程节选